baker hughes inteq's guide to measurement while drilling information guide

Baker Hughes INTEQ

Baker Hughes INTEQ’s Guide To Measurement While

Drilling

Information Guide

750-500-077 Rev. A September 1997

Baker Hughes INTEQTechnical Communications GroupP.O. Box 670968Houston, TX 77267-0968USA713-625-4415

sed ; ther ed

This manual is provided without any warranty of any kind, either expresor implied. The information in this document is believed to be accuratehowever, Baker Hughes INTEQ will not be liable for any damages, whedirect or indirect, which results from the use of any information containherein.

© 1997 Baker Hughes INTEQ

Information Guide750-500-077 Rev. A / September 1997

Preface

ce e new oss

l s or

14.

The purpose of this document is to provide a general introduction to “Measurement While Drilling” technology and applications. The audienis expected to be engineers, scientists, and technical managers who arto this field. This guide discusses MWD technology that is common acrthe oil services industry as well as specific to Baker Hughes INTEQ.

This document is produced by both the Technical Services Group andAdvanced Development Group of the Drilling and Evaluation TechnicaCenter. The material in this document is a result of the efforts of manypeople, both in the above mentioned groups and outside. Any questioncomments can be directed to:

Frank Hearn, Senior Technical Advisor (713) 625-4619 or Hatem Nasr, Manager, Advanced Development Group (713) 625-47

-iii

Baker Hughes INTEQ’s Guide to MWD

-iv Baker Hughes INTEQ750-500-077 Rev. A / September 1997

Table of Contents

. 1-1. . 1-11-11-3 . . 1-41-41-4-5 . 1-5 . 1-5-6 . 1-7

2-1. . 2-1. . 2-2. . 2-3

2-4. . 2-4. . 2-5 . 2-5

2-6 . . 2-6. . 2-6

. 2-7 . 2-7. . 2-7-8

Table of Contents

Chapter 1

Measurement While Drilling

MWD History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .What Is MWD? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mud Pulse Telemetry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Information Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Early Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Pre War Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Post War Developments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Development in the Seventies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Typical Early Operational Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Evolution - Development in the Eighties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Development in the Nineties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Typical Current Operational Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 2

MWD Principles

Three Basic Telemetry Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Positive Mud Pulse Telemetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Negative Mud Pulse Telemetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous Wave Telemetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Other Telemetry Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Electromagnetic Telemetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acoustic Transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fluidic Vortex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Coding / Encoding Schemes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Enhanced Return to Zero Technique Telemetry . . . . . . . . . . . . . . . . . . . . . . .Digital Encoding Techniques. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tool Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clear 2" ID / Centrally Located . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Modular / One Piece Multi-sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Collar Mounted MWD Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

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2-92-9. 2-11. 2-12

2-14

-15

-17

2-18

2-18

. 3-1

. 3-1 . . 3-1. 3-13-1. 3-2. 3-3-3

3-43-43-4

. . 3-6

. 3-63-6. 3-6. 3-7-7

3-8-83-8

-8-9-10

Probe MWD Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Battery / Turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Retrievable / Non Retrievable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Memory / Real Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Magnetic Interference/Spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Hydraulics / Drilling Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Maintenance / Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 3

Formation Evaluation MWD

Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sensor Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Natural Gamma Ray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Measurement Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Environmental Corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Background Radiation from Drilling Fluid. . . . . . . . . . . . . . . . . 3-3Mud Density. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Hole Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Correction Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MWD and Wireline Gamma Ray Comparisons. . . . . . . . . . . . . . . . . . . . 3-4

Formation Resistivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Measurement Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Environmental Corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Borehole Fluid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Hole Size and Tool Size. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Bed Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MWD and Wireline Resistivity Comparisons . . . . . . . . . . . . . . . . . . . . . 3-8Short Normal Resistivity (SNR). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Measurement Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

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-22-22-2233-2683-303-30-30

4-34-34

3-363-3636379-39-39

-40

-41

Focused Current Resistivity (FCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1Measurement Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-

Toroidal Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Electromagnetic Wave Propagation Resistivity . . . . . . . . . . . . . . . . . . 3-14

Measurement Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-Depth of Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Environmental Corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2MWD and Wireline DPR Comparison. . . . . . . . . . . . . . . . . . . . 3-21

Geo-steering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Modeling Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3MWD Geosteering Log Example. . . . . . . . . . . . . . . . . . . . . . . . 3-2

NaviGator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Multiple Propagation Resistivity (MPR). . . . . . . . . . . . . . . . . . . . . . . . 3-2

Neutron Porosity MWD Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Measurement Theory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Neutron Porosity Detection and Measurement. . . . . . . . . . . . . 3-31Environmental Considerations . . . . . . . . . . . . . . . . . . . . . . . . . 3-3Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Verification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Gas Detection with Neutron Near/Far Count Overlay . . . . . . . . . . . . . 3-35Formation Density MWD Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Measurement Theory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-Gamma Ray Interaction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-Environmental Considerations . . . . . . . . . . . . . . . . . . . . . . . . . 3-3Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Triple Combo Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Data Integration at the Wellsite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

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. 4-1

. 4-1. . 4-1. . 4-2. . 4-2. . 4-24-3. 4-3. 4-44-44-4. . . 4-5 . . 4-5. 4-5 . 4-6

. 4-7. 4-7. 4-7 . 4-7. . . 4-7. 4-7 . . 4-7

. 5-1

A-2

. A-5

-12

Chapter 4

Drilling Performance MWD

Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sensor Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Measurement Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inclination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Azimuth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Toolface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Measurement Theory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Primary Verification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Secondary Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pressure Transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Downhole Weight on Bit / Torque on Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Downhole Shock and Vibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Directional Drilling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drilling Optimization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Avoidance of Drill Pipe Damage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Swab and Surge Measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Influx Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Research Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 5

MWD Market

MWD Marketplace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 6

Conclusion

Chapter A

MWD Bibliography

Overview And History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Data Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Drilling And Mechanical Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A

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A-21

-22

-25

29

-30

34

35

38

-39

-40

A-40

A-45

A-45

-49

Drilling And Mechanical Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-

Directional Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Directional Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A

Sensors And Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A

Formation Evaluation Tools - General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-

Mwd Interpretation - General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A

Gamma Ray Tools and Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-

Resistivity Tools And Interpretation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-

Neutron Tools And Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-

Density Tools And Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A

Radiation And Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A

Horizontal Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pore Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vertical Seismic Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A

Information Guide v750-500-077 Rev. A / September 1997


vi Baker Hughes INTEQ 750-500-077 Rev. A / September 1997


Chapter
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Measurement While Drilling MWD History

What Is MWD?

Measurement While Drilling (MWD) systems measure formation properties (e.g. resistivity, natural gamma ray, porosity), wellbore geometry (inclination, azimuth), drilling system orientation (toolface), amechanical properties of the drilling process. Traditionally MWD has fulfilled the role of providing wellbore inclination and azimuth in order tmaintain directional control in real time. From the mid 1980s to the prestime, formation evaluation MWD has paralleled and surpassed other aspects of drilling technology to the extent that it is now possible to repvery sophisticated wireline logs with real-time and memory-stored measurements while drilling.

Mud Pulse Telemetry

The MWD tool is normally placed in the bottom hole assembly of the drillstring, as close to the drill bit as possible. The MWD tool is an electromechanical device which makes the measurements described aand then transmits data to surface by creating pressure waves within tmud stream inside the drillpipe. These pressure waves or pulses are detected at the surface by very sensitive devices (standpipe pressure transducers with pre-amplifiers) which continuously monitor the pressuof the drilling mud. These data are passed on to sophisticated decodincomputers which deconvolute the encoded data from downhole. This whole process is virtually instantaneous, thus, enabling key decisions made as the wellbore is being drilled.

Other, more exotic transmission systems do exist e.g. drillpipe acoustielectromagnetic and hardwire telemetry. But the vast majority of all commercial systems utilize mud pulse telemetry by generating either apulse or a modulated carrier wave which is propagated through the drifluid at roughly the speed of sound in mud (i.e. 4000-5000 ft./sec or 121500 m/sec). Mud pulse telemetry MWD tools use positive pulse, negapulse or carrier wave (mud siren) schemes to transmit measured paramfrom downhole to surface in realtime to aid in formation evaluation, directional control, drilling efficiency and drilling safety. Downhole information is registered by the MWD sensors and then passed on to tMWD tool microprocessor. The microprocessor then routes this

1-1

Measurement While Drilling Baker Hughes INTEQ’s Guide to MWD

ud hin ted. a ed

e

st

nd lace.

information to the surface by activating the tool transmission system. Mpulse telemetry involves the modulation of the flow of mud through thedrillstring by means of a mechanical valve or rotary valve mounted witthe MWD tool. At the surface, the data are decoded and depth correlaThe data are then output to hard copy and graphical display, much likewireline logging system. The true value of MWD can thus be appreciatby its provision of realtime dynamics and directional drilling data augmented by realtime formation evaluation measurements, which areconsidered equivalent and often times superior to sophisticated wirelinlogs.

As MWD tools and measurements have become more reliable and coeffective, the practice of replacing both standard (e.g. gamma ray, resistivity) logs and triple combo (which also include neutron porosity aformation density measurements) wireline logs has become common p

Figure 1-1 MWD System

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ed

)

The superior cost effectiveness of MWD logging is especially true for medium to high cost development wells and high risk drilling applicatiowhere problems with hole geometry, displacement and logging environment preclude the use of wireline logs other than those conveyby drillpipe or tubing. This drillpipe-conveyed wireline process is both costly and time consuming, particularly when the high cost of fourth orfifth generation drilling rigs and platforms are considered.

Several key factors will drive the MWD vs. wireline decision making process:

• Deviation of wellbore

• Anticipated borehole conditions at logging time

• Risk of losing hole or tools during wireline operations

• Value of early data acquisition

• Rig costs and required operating time

• Ease of fishing (bottom hole assembly vs. wireline cut and thread

• Value of realtime data to reservoir and geologic uncertainty

Information Output

Depending on the level and complexity of the MWD service used, applications include:

• Directional control

• Relief well drilling

• Bottom hole location

• Casing seat selection

• Gas influx identification

• Lithological identification

• Offset well correlation

• Coring point selection

• Invasion profiling

• Pore pressure analysis

• Precision geosteering in high angle wells

• Hydrocarbon identification

• Shallow gas control

• Reconnaissance and insurance logging in high risk wells

Information Guide 1-3750-500-077 Rev. A / September 1997


s

etry

ble

d for

on

• Cost effective wireline replacement

Where drilling mechanics MWD is used, it may be possible to provide information to aid in the following:

• Drilling optimization

• Hydraulics optimization

• Bottom hole assembly damage avoidance

• Bit whirl analysis

• Influx monitoring (well kick)

• Swab and surge measurements while tripping (avoiding kicks or conversely formation damage)

Early Systems

Pre War Development

1927 First wireline log run in France by Schlumberger brother

1929 Jakosky filed a patent on the concept of mud pulse telem

Early'30s Karcher of GSI attempted continuous resistivity transmission by means of conducting rods fastened in drillpipe

Early'40s Silverman of Stanolind Oil & Gas Co. used an electric cainside drillpipe for data transmission

By 1950 Mechanical weakness of insulated subs/sensors and neecustom drillpipe led to abandonment of early telemetry systems. Mud Logging/wireline became accepted formatievaluation methods

Post War Developments

1950's Arp invented the positive mud pulse system, developedjointly by Arps Corp. and Lane Wells

Early '60s Above development resulted in a number of successful gamma ray/resistivity runs

Late '60s Redwine & Osborne developed a “While Drilling Monoelectrode Resistivity Log”Teledrift tool developed - mechanical inclinometer with positive mud pulse - still used today in North Sea Godbey of Mobil developed mud sirenFlexodril system developed by IFP



try

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l

)

Late ‘60s ELF worked on positive mud pulse telemetry system, leading to creation of Teleco which evolved into the indusbenchmark for service, reliability and performance

By 1970 Design problems and lack of economic drivers led to decin MWD research

Development in the Seventies

Early '70s Resurgence of interest in MWD driven by OPEC cartel aimproved technology Development of SNAP logs by ELF(Early version of surface measured drilling dynamics - akto ADAMS and DYNABYTE)

1971 First successful test of mud siren by MOBIL R & D

1970-73 B J Hughes running commercial Teledrift tool

1972 ELF and Raymond Engineering form a joint venture calleTELECO

1978 First commercial MWD system - TELECO Directional MWD

1979 Gearhart Owen - NPT Dir/GR tool commercial

Typical Early Operational Specifications

Survey Time 4-5 minutes

Tool Face Update 2 minutes

Collar Size 7-3/4” to 9-1/2”

MTBF 50 Hours

Evolution - Development in the Eighties

1980 Schlumberger / Anadrill commercial with MST multi-sensor MWD licensed from MOBIL Gearhart commerciawith NPT multi-sensor MWD

1981 Gentrix (EASTMAN) PPT directional MWD commercial

EXLOG commercial with NPT multi-sensor MWD with memory

1983 Teleco introduce RGD commercial system

1984 NL Baroid commercial with RLL (Recorded Lithology Loga recorded Electromagnetic resistivity / gamma ray log

EXLOG introduce DHVM system - downhole vibration measurement



nt

l

t

M

t

ith

k

a

1984 Teleco, EXLOG, Anadrill, Gearhart all offering RGD services

1985 Teleco and Anadrill introduce Bit Mechanics Measureme

EXLOG commercial with retrievable Dir DMWD probe too

1986 NL Baroid introduce Neutron Porosity measurement withRLL

Gearhart introduce lateral and bit resistivity measuremen

1987 EXLOG commercial with focused current resistivity

1988 Gearhart commercial with focused gamma ray sensor

1989 ENSCO enter MWD market - small RGD presence in GO

1989 NL Sperry introduce triple combo MWD

Anadrill/Schlumberger introduce triple combo LWD and MEL/SPIN software

Teleco introduce Dual Propagation resistivity

Development in the Nineties

1990 Teleco commercial with triple combo MWD

1991 NL Sperry introduce EWR Phase 4 - multiple DOI EWR

Western Atlas introduce 1 MHz RGD

Anadrill purchase Positech - market as Slim 1 retrievabletool

1992 Anadrill introduce IDEAL (Integrated Drilling Evaluation and Logging) System with inclusion of RAB (Resistivity ABit) and Acoustic Caliper.

Baroid (NL Sperry) introduce Near Bit Inclinometer

Baker Hughes acquire Teleco - new company merges wEastman Christensen. World leading MWD and drilling performance company renamed EASTMAN TELECO

Baker Hughes commercial with slim hole Dir/GR NaviTratool

Baker Hughes INTEQ introduces Modular Drilling Dynamics sub

1993 Smith International sold 'Performance Drilling Systems &Services' to Halliburton in Jan 1993. (Halliburton GeodatLtd.). Anadrill/Schlumberger introduce MWD downlink andshort hop technology.



e

.

s)

Baker Hughes INTEQ is formed. A fully integrated serviccompany is formed through the merger of EASTMAN TELECO, DEVELCO, MILPARK DRILLING FLUIDS, EXLOG, and BAKER SAND CONTROL

1994 Baker Hughes INTEQ introduce NaviTrak Short Radius MWD system and NaviGator reservoir navigation system

1995 Commercial slim hole propagation resistivity (4-3/4” tooldeveloped - Sperry Sun Slim Phase 4 (memory only), Schlumberger ARC-5, Baker Hughes INTEQ NaviMPR. IDS and Halliburton develop prototype tools.

Typical Current Operational Specifications

Survey Time 90-130 seconds

Tool Face Update 9-18 seconds

Collar Size 3-1/8” - 9-1/2”

MTBF 300 Hours + Dir

200 Hours + FEMWD

Sensor Array Slim Hole - DIR, DIR/GR, 2MHz and 400kHz RESISTIVITY (NaviMPR)

Large Hole - DIR, DIR/GR,

DRILLING DYNAMICS, RGD,

2MHz and 400kHz RESISTIVITY (NaviGator), NEUTRON POROSITY, DENSITY, Pe, CALIPER



•Notes•



Chapter
2
ssure e.

d

MWD PrinciplesThree Basic Telemetry Types

Positive Mud Pulse Telemetry

Positive mud pulse telemetry (MPT) uses a hydraulic poppet valve to momentarily restrict the flow of mud through an orifice in the tool to generate an increase in pressure in the form of a positive pulse or prewave which travels back to the surface and is detected at the standpip

Service companies and respective services using this telemetry methoinclude:

Baker Hughes INTEQ - D, DG, DDG, RGD, DPR, MPR, TC, NaviGator, DMWD, NaviTrak and NaviGamma

Anadrill/Schlumberger - SLIM1

Halliburton - Datadrill

Sperry Sun - DWD/DGWD/FED

Figure 2-1Positive Mud Pulse Telemetry

2-1

MWD Principles Baker Hughes INTEQ’s Guide to MWD

he in

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od

Negative Mud Pulse Telemetry

Negative MPT uses a controlled valve to vent mud momentarily from tinterior of the tool into the annulus. This process generates a decreasepressure in the form of a negative pulse or pressure wave which traveback to the surface and is detected at the standpipe.

Service Companies and respective services using this telemetry methinclude:

Baker Hughes INTEQ - AccuTrak

Computalog - D, DG

Geolink - D, DG

Halliburton - AGD/BGD, RGD

Sperry Sun - MPT

Figure 2-2Negative Mud Pulse Telemetry


Baker Hughes INTEQ’s Guide to MWD MWD Principles

o face

od

Continuous Wave Telemetry

Continuous wave telemetry uses a rotary valve or “mud siren” with a slotted rotor and stator which restricts the mud flow in such a way as tgenerate a modulating positive pressure wave which travels to the surand is detected at the standpipe.


Anadrill/Schlumberger - MWD and LWD

Figure 2-3Continuous Wave Telemetry



Hz) nd at e floor. ial ter ids

ith

Other Telemetry Types

Electromagnetic Telemetry

The electromagnetic telemetry (EMT) system uses the drill string as a dipole electrode, superimposing data words on a low frequency (2 - 10carrier signal. A receiver electrode antenna must be placed in the grouthe surface (approximately 100 meters away from the rig) to receive thEM signal. Offshore, the receiver electrode must be placed on the sea Currently, besides a hardwire to the surface, EMT is the only commercmeans for MWD data transmission in compressible fluid environmentscommon in underbalanced drilling applications. While the EM transmithas no moving parts, the most common application in compressible flugenerally leads to increased downhole vibration. Communication and transmission can be two-way i.e. downhole to uphole and uphole to downhole. The EM signal is attenuated with increasing well depth and wincreasing formation conductivity.

Figure 2-4Electromagnetic Telemetry



od

An hich h,

in use ic

rca 1


Geoservice - D and DG

Sperry Sun/Geoscience - D and DG

Mitsubishi/JNOC - Experimental system

Acoustic Transmission

Acoustic transmission systems can be described as active or passive.active acoustic system generates a downhole sonic telemetry signal wpropagates up the drill string. Though data rates are generally very higsignificant attenuation of the acoustic signal occurs at drillpipe connections. Thus, “repeaters” (acoustic amplifiers) are often requiredthe drill string as well depth increases. Passive acoustic systems makeof pre-existing downhole acoustic energy (such as bit noise) as a seismenergy source for seismic while drilling measurements.

Fluidic Vortex

The fluidic pulser generates a vortex within a chamber by momentarilyrestricting the mud flow, thus creating a turbulent flow regime. The resulting change in pressure loss can be switched on and off rapidly, cimillisecond, and the resultant pressure wave created can be of high amplitude (145 psi).



s he

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ment

d

data

w,

nal data

Coding / Encoding Schemes

Enhanced Return to Zero Technique Telemetry

Unipolar pulses are generated from a baseline in combinatorial patternwithin a fixed time interval or by employing phase shift keying (PSK). Toriginal MWD system would transmit a number of pulses, or pressuressurges, which could be detected and decoded at surface. By the late seventies new systems were introduced which enhanced mud pulse telemetry with two new concepts, time-analog and binary return to zerThese conventional mud pulse systems have three common features:

• Unipolar Pulses

• They all Return to Zero

• All Rely on Constant Pulse Width

Enhancements to common RZ methodologies have led to the developof M-ary Phase Shift Keying (MPSK) and Combinatorial Coded (CC) telemetry.

Digital Encoding Techniques

Three additional encoding schemes are now available for optimum mupulse telemetry:

• Non Return to Zero (NRZ)

• Delay Modulation (Miller)

• Bi-phase

The encoding schemes listed have common attributes:

1. All are implementations of binary encoding schemes.

2. These techniques use change in state, or transition, for eachbit instead of using pulses like RZ code.

3. Each transition must occur within a relatively short time windoor bit cell.

4. The success in using these methods hinges on the digital sigprocessing capabilities of the surface computer decoding the stream. Hand decoding is usually not an option.



s a g

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tor

ions

y. By l of

Tool Configurations

There are a wide variety of MWD tool configurations dependent on application, measurement specification and drilling environment.

Five differing configurations are defined:

• Clear 2" ID / Centrally Located

• Modular / One Piece

• Battery / Turbine

• Retrievable / Non retrievable

• Memory / Real Time

Clear 2" ID / Centrally Located

Some MWD tools, such as the Baker Hughes INTEQ AccuTrak tool, haclear 2" ID through bore which permits unobstructed mud flow, allowinvirtually any type of LCM to pass by/through the MWD tool, and if necessary it is possible to effectively string-shot below the MWD tool.

Modular / One Piece Multi-sensor

Modular MWD systems were designed to address the growing need fobroader, more flexible range of service levels. The key to a modular MWsystem is the interconnection of the tool modules over a single conducpower and data bus. This is accomplished by using either a stab-in

connector or a tool shoulder ring connector in order to provide connectfor the addition or deletion of tool modules to the drillstring, including custom components, such as full or undergauge stabilizers, if necessarhaving this type of architecture, it is possible to build the required leve

Figure 2-5One Piece Multi-sensor



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or

er).

service from a simple directional service to a full triple combo MWD service. As with other major MWD service companies, Baker Hughes INTEQ MWD utilizes a modular concept that is offered in two systems

• a collar mounted system which utilizes a dedicated drill collar

• probe mounted system that is placed in the ID of a standard monecollar.

These two systems enable the provision of MWD services for slim holedirectional, real-time, multi-sensor, and recorded only MWD services fthe oil and gas industry. Modular MWD systems of the nineties providesignificant computational processing power, with both transmission sampling and recording formats that are programmable at the wellsite.

Collar Mounted MWD Systems

Generally, collar mounted MWD systems are available down to 6-3/4” collar sizes (i.e. they are suitable for 8-1/2” to 9-7/8” hole sizes and larg

Figure 2-6Collar-basedDirectional



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in tes)

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ng

rd

um lso ed

for

Modular MWD components can be selected to build two major servicelevels (each with expandable options):

Directional (D) / Directional Gamma (DG)

These collar mounted services provide real-time directional and directional-gamma tool data using mud pulse telemetry. Power is provby a downhole turbine.

Real-time and memory-stored Multi-Sensor

This group of services combines several tools to provide real-time formation evaluation and directional information. Data are transmitted real-time by mud pulse telemetry and are also stored (at higher data rainto downhole memory to enable enhanced log definition following bit trips.

Probe MWD Systems

Typically, this is a battery operated, negative or positive pulse MWD system designed for simplicity of operation and ease of maintenance. tool's sensors and electronics are fitted inside either a 1-3/4 inch or 2 i(51mm) OD protective housings or “barrels”. The adjoined barrels are placed inside a standard Non-Magnetic Drill Collar (NMDC) and are stabilized with integral rubber centralizers (fin or flex style). Although initially designed for slim hole applications, the MWD probe systems aused in all BHA dimensions. Current configurations permit these typestools to be run in collar sizes ranging from 3-1/8” up to 9-1/2”.

Probe MWD components can be selected to build two major service le

Directional

These services provide real-time directional and temperature data, usimud pulse telemetry. Power is provided by a lithium battery pack.

Real-time Multi-Sensor

This group of services combines a gamma-ray module with the standaMWD configuration to provide both real-time formation evaluation anddirectional information. Slim hole, advanced propagation resistivity (including downhole memory) is also available in a probe style systemtargeted for the 4-3/4” collar size.

Battery / Turbine

With battery operated MWD systems, power is usually supplied by lithichloride batteries. This enables the tool to operate while tripping and aenables operation independent of mud flow hydraulics. Turbine powersystems generate power by the flow of mud, so they will only operate within preset flow ranges. It is necessary, therefore, to have circulation



th
the tool to operate. The following summarizes the characteristics of bosystems:
Table 1: Battery versus Turbine-Powered MWD Systems

Battery Powered Turbine Powered

Lithium Battery Mud turbine/alternator

Power hour limits No time limits

Power with and without circulation Must circulate to power system

150 degC operating limit 125 degC operating limit

Figure 2-7Navi-Gamma and Directional Gamma Systems



e run r. If sand the ust de

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-to-

ture . In ar de up

Retrievable / Non Retrievable

There are many play offs when attempting to categorize the relative advantage of a retrievable, versus a “dedicated” non retrievable, MWDtool. Ultimately, the choice is governed by drilling application and operational costs.

A fully retrievable MWD system offers flexibility, convenience and reduced lost-in-hole liability. Typically, a probe is shipped to the wellsitby truck or helicopter and made up on the catwalk. The system is theninto place to a landing shoe in a non-dedicated non magnetic drill collaa tool failure does occur, the tool can be retrieved from downhole on a line and is easily replaced by running a back up tool into place withoutneed to trip the drillstring. Typically, these types of tools are simple robdirectional MWD tools. Recently, a gamma ray capability has been maavailable with the Baker Hughes INTEQ NaviTrak Gamma tool. For thfuture, an electromagnetic resistivity capability is expected. The niche market for this type of device is remote location, slim hole and mediumshort radius horizontal drilling applications.

The non retrievable MWD system is typically more sophisticated and reliable than its retrievable counterpart. This is due to the dedicated naof the tool and its encapsulating collar. As the tool is locked down, it isinherently more reliable and able to operate in higher mud flow regimesaddition, the capability exists to use add-on sensors as with the modultool design described earlier, so that a particular set of tools can be mafor a specific drilling application. Theoretically, this add-on capability is

Figure 2-8Retrievable NaviGamma Tool



ls e of ith of a For

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h is r or

e face, data uced rate

ay

n

also possible for retrievable tools, although this is a topic for future development.

Memory / Real Time

Most commercial real-time and recorded only formation evaluation toohave an enhanced memory capability. This system provides for storagraw data and permits storage of data at higher rates than is possible wreal-time transmissions. The memory system is also used for retrieval formation data if only toolface data are transmitted when steering. Datstorage also provides data recovery in case of transmission problems.example, if real-time data are lost due to surface detection problems, memory data can be used to fill in the missing information. The chancememory filling up on long bit runs is a possibility but rare in todays' marwhere MWD memory systems are normally between 0.5 and 8 Megab

Memory Only Services

A number of service companies offer a recorded only service level whicdesigned to provide downhole recorded formation evaluation at a lowecost than real-time data acquisition. Ideally, this service will be utilizedwhere costs are critical since formation evaluation data are essential fdiscriminatory purposes, but are not needed in real-time. Formation evaluation data are continuously logged into the tool memory on a timbasis, regardless of rig operations. When the tool is retrieved at the surthe memory is dumped through a high speed sidewall data port. Theseare then matched with a prerecorded time/depth array and a log is prodin a matter of minutes. Since this is a recorded only service, it can opeindependently of a mud logging unit in a safe working area or from a third-party logging unit.

The basic level of recorded only service will include a natural gamma rlog and a 2 MHz electromagnetic resistivity sensor (DPR). Additional enhancements include advanced propagation resistivity (MPR), neutroporosity (MNP) and formation density (MDL) measurements.

Applications

• Lithological identification

• Formation bed boundary and thickness determination

• Casing seat selection

• Shale formation estimates in reservoir rocks

• Low cost insurance logging in high risk wells

• Permeability/sedimentology studies



of

l ach . n, t.

PEI

Real-time Multi-sensor

Real-time multi-sensor MWD services are designed to meet the needstoday's demanding drilling environment. Levels of service range from simple directional to full real-time formation evaluation with enhanced downhole recording. For example, in a surface hole section, directionacontrol may be the only MWD requirement. In contrast, an extended rehorizontal well could utilize full formation MWD for insurance purposesBy using full formation evaluation to provide real-time logs for evaluatioit is possible to make cost effective decisions in critical reconnaissancedrilling situations. In today's challenging drilling environments the MWDlogs obtained may ultimately serve as the definitive log if the well is losFor more details on real time MWD service configurations, refer to the MWD comparison tables.



d

Reliability

Reliability is the probability of a product performing without failure, a specified function under given conditions for a given period of time.

A unit of measure is Mean Time Between Failure (MTBF). The Baker Hughes INTEQ method for calculating MTBF strictly adheres to the guidelines laid down by the Society of Petroleum Engineers (SPE) endorsed in publication 19862 “Recommendations for MWD Tool Reliability Statistics”. In this respect, the reliability standard is expresseas follows:

Factors Affecting Reliability:

• Shock and Vibration

• Downhole Temperature

• Complexity of Tool

• Drilling Practices

• Telemetry System

• Service Company Quality Assurance (TQM)

• Competition

• Training

Reliability MTBFOperating Hours (Perfect Hours)

Failures------------------------------------------------------------------------------= =



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Magnetic Interference/Spacing

The MWD directional survey instrument is used to monitor the directio(magnetic) and inclination (the angle of the tool's long axis from verticaof the borehole.

In the MWD drilling environment, there are many sources of magnetic interference that can cause inaccurate directional measurements. A ferromagnetic steel object that is placed in a magnetic field will becommagnetized. The amount of induced magnetism is a function of the extefield strength and magnetic permeability of the object. In order to prevemagnetic interference, the directional survey instrument is housed in amagnetic stainless steel collar. The MWD tool is usually arranged in asection of the bottom-hole assembly (BHA) which is made up of a serienon-magnetic collars to reduce the impact of the drilling assembly's stecomponents on the magnetic field at the location of the survey sensor.

It is possible to optimize the position of the survey instrument by estimating the pole strength for various BHA configurations, based upodownhole field measurements. However, even if the correct non-magncollar spacing is used, there could still be other sources of magnetic interference which will cause erroneous directional readings. These inc“hot spots” in the non-magnetic steel or areas of mechanical damage caused by rethreading/welding or manufacturing impurities. A continuaquality assurance procedure ensures that such anomalies are not presMWD collars and stabilizers. More significantly, other BHA componentmay be made of magnetic material and/or already have magnetic anomthat affect azimuth readings. Other sources of magnetic interference mbe caused by proximity to iron and steel magnetic materials from prevdrilling or production operations, magnetic properties of the formation, aconcentrations of magnetic minerals (iron pyrites, etc.) in excess of sixpercent.

Figure 2-9Magnetic Interference



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ted

bias tor to en

muth h tion

to th

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otate ate,

Azimuth Correction Technique

It is often advantageous to reduce the number of non-magnetic drill coso that the directional and formation evaluation sensors can be locatedcloser to the bit. (This also eliminates the extra cost of using monel collars.) This will assist in real-time decision making by allowing readinto be made as soon as possible following formation penetration. To addthis problem, a number of methods have been devised for making corrections to magnetic surveys. The following correction techniques adesigned to reduce the influence of spurious magnetic fields associatewith the BHA:

Magnetic Azimuth Correction Algorithm

This is a proprietary method by which magnetic azimuth can be calculain the event that the z-axis magnetometer reading is corrupted by a spurious longitudinal field resulting from an insufficient length of non-magnetic BHA components. The tool senses such a spurious field as aon the z-magnetometer measurement. The method requires the operaspecify expected values for total magnetic field and dip angle, and it thcomputes the azimuth angle which is consistent with a magnetic field vector as close as possible to the expected value. Accuracy of this aziangle is dependent on the accuracy of the input nominal values for theearth's magnetic field and gravity field. The corrected magnetic azimutaccuracy is dependent on the surface location of the well and the direcand inclination that is being drilled. At higher latitudes and higher inclinations and the farther the direction is from north or south, the accuracy of the corrected azimuth will degrade. The operator will havedecide whether to use the corrected azimuth or the uncorrected azimubased on concerns for azimuth accuracy.

Rotation Algorithm

This is a refinement to the Magnetic Azimuth Correction Algorithm abowhich makes use of downhole tool rotation to reduce errors caused byin x-axis and y-axis magnetometers, in addition to the z-axis magnetombias. Also, accelerometer bias errors on the x-axis and y-axis can be reduced with this procedure. Such biases may be caused not only by calibration drift, but also by magnetic hot spots in the drill collar or by magnetic junk affixed to the outside of the collar. This method requiresminimum of three surveys at different toolface angles, to define a circlecentered at a point which represents the transverse biases.

This method can reduce errors caused by magnetic anomalies which ras the survey tool is rotated. It does not reduce errors which do not rotsuch as interference from an adjacent casing string.



rs der to ump ed in ump e any

n,

ncy MS

he w

Hydraulics / Drilling Factors

There are a number of sources of interference in the MWD drilling environment, although the main ones are as follows:

Mud Pump Noise

Excessive noise, either from the mud pumps or high torque mud motocan, in rare instances, create unacceptable signal to noise ratios. In orprevent this, some MWD companies deploy surface measurement of pstrobes in order to characterize a mud pump signature. This is then usthe surface decoder as a pump subtraction filter. In many cases, the psubtraction filter can be used to detect premature pump damage beforother physical signs are available.

Rig and Drillstring Noise

Drillstring vibration will, typically, generate high frequency noise whichcan lead to a dramatic deterioration of the transmitted signal. Very ofteby simply making adjustments to the WOB and RPM, it is possible to avoid damaging critical torsional and lateral resonance. A number of vibration prediction programs are available which can estimate critical RPM for a given drilling assembly. It is also possible to use high frequesurface measurement devices, such as the Baker Hughes INTEQ ADAand DynaByte technology provided by the Drilling Dynamics Group. (TDrilling Dynamics Group within Baker Hughes INTEQ uses EXLOG (nopart of Baker Hughes INTEQ), ARCO and ELF patented surface measurement technologies)



ved

on IV.

Maintenance / Training

Periodic MaintenanceStandard Procedures

Data TrackingDesign Simplicity

all add up to

Quality Assurance SystemPreventive Maintenance Decreases Costs

Calibration

Calibration is defined as the verification of a measurement to an appronational and/or international standard.

This is a very important subject that will be explained in greater detail an individual basis for each of the sensors described in sections III and



Chapter
3
n

y. asic e

e

e

ly der.

ma

ay, and

Formation Evaluation MWD

Definition

MWD instrumentation provides information for directional control and formation evaluation analysis. Formation evaluation MWD provides accurate, quantitative measurements of resistivity, gamma ray, neutroporosity and formation density.

Sensor Information

Natural Gamma Ray

Introduction

All of the earth's rock formations exhibit varying degrees of radioactivitThe gamma ray log is a measurement of the natural radioactivity of theformations. The measurement of this natural radioactivity has been a bwireline log parameter for many years. Gamma ray logs are used as thdepth reference log for correlation with other log information. Since natural gamma ray is a fairly simple measurement to make, this was thfirst commercial MWD formation evaluation measurement to be made available in the mid-1970's.

Measurement Principle

Two basic types of detectors are used by MWD companies to measurgamma rays:

The Geiger Muller tube is a gas ionization counter consisting of a metal cylinder with an insulated axial wire passing through its center. The cylinder is filled with a non-conductive gas. A high voltage power suppmaintains an electrical potential between the central wire and the cylinThe main detection mechanism is photoelectric absorption or recoil electron ejection from Compton scattering in the metal shield. For gamrays absorbed near the inner radius of the cylinder, there is some probability of the ejected electron escaping into the gas to provide the initial ionization of the detector gas molecules. Electrons, freed in this ware accelerated by the radial electric field, collide with gas molecules,

3-1

Formation Evaluation MWD Baker Hughes INTEQ’s Guide to MWD

ted of e g of

ge over

e

in a

y d

produce additional free electrons. A fraction of the electrons are collecat the central wire, producing a voltage pulse. The detection efficiencysuch detectors is not high, even so the method can be improved by thincorporation of gamma ray absorbers (such as silver) to an inner lininthe cylinder.

With the more efficient scintillation detector used in Baker Hughes INTEQtools, a crystal of thallium-doped sodium iodide emits light flashes or scintillations when a gamma ray interacts with the crystal. A high voltaphotomultiplier tube captures the scintillations, amplifying them into anelectrical signal in the form of a count rate. Gamma rays are measureda specified time in order to collect enough counts to reduce statistical scatter.

Applications

The measurement of natural gamma ray activity is used to estimate thshale content of sedimentary rocks. This lithology discrimination is possible because of the presence of radioactive isotopes (potassium, thorium, and uranium) in the minerals associated with rock types. Thenumber of gamma rays emitted per unit time is a function of the concentration and distribution of these isotopes, and can be correlatedgeneral way to lithology. The following type log reveals gamma ray response by formation type. Note that actual gamma ray levels will varwidely by location, even so, the log is still useful for discriminating san(or non-shale lithologies) from shale.

Figure 3-1Natural Gamma Ray Activity


Baker Hughes INTEQ’s Guide to MWD Formation Evaluation MWD

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PI

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ator ning en

r

bles:

tion

ich

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In addition to providing lithologic discrimination, the gamma ray sensoprovides:

• Formation bed boundary and thickness determination

• Well to well structural correlation of beds

• Depth control and casing seat selection

• Estimation of shale fraction in reservoir rocks

• A primary log for sedimentological studies

• Monitoring of injected radioactive materials

• Depth location of radioactive casing PIP tags

Calibration

Count rates from the photomultiplier tube are scaled to API units. The primary calibration standard for the natural gamma ray sensor is the AGamma Ray Calibration Facility in Houston, Texas.

Baker Hughes developed a technique for transferring the calibration oAPI pit to a portable wraparound calibrator (Meisner, et. al., 1985). Background counts are determined with a nonradioactive empty calibrin place. The empty calibrator is then exchanged for a calibrator contaia gamma ray source with a spectrum equivalent to the API pit, and a tminute count rate is performed. The values are then corrected for the attenuation caused by the replacement of the air in the collar with wateand the attenuation caused by the drill collar itself.

Environmental Corrections

The gamma ray measurement is affected by three environmental varia

Background Radiation from Drilling Fluid

Most drilling fluids have negligible radioactivity; however, saturated potassium chloride mud systems (KCl) have a significant level of radiafrom naturally occurring radioactive potassium isotopes (potassium is highly soluble and can enter the formation). Bentonite (gel additive) is rin thorium and uranium. Some low grade barite may also have naturalactivity. These contaminants produce offsets on the log which are particularly noticeable if levels of potassium are rapidly changed. Althouit is possible to correct for this offset, the correction is seldom performeit is very difficult to ascertain precise downhole concentration levels whvary with fluctuations in mud properties.



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ector and is

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m D

/or

Mud Density

Increases in mud density will increase the attenuation of gamma rays the formation to the tool. Charts and real-time algorithms are availablecorrect for this effect.

Hole Size

An increase in borehole diameter attenuates the gamma ray tool's detresponse, due to an increased volume of drilling fluid between the toolthe formation. Charts and algorithms are also available to correct for theffect.

Correction Standards

It is standard Baker Hughes INTEQ practice to apply the environmentacorrections for mud density and hole size. Two separate SPWLA standare in use, one for wireline tools, (8-inch hole, 10 lb/gal density) and ofor MWD tools, (10-inch hole, 10 lb/gal density). Baker Hughes INTEQcan provide real-time correction for either standard.

MWD and Wireline Gamma Ray Comparisons

Some fundamental differences exist between MWD and wireline gammray data, and only rarely do the logs overlay exactly. Statistical variatioassociated with MWD logs are often considerably less than those of wireline because wireline logging speeds are greater (1800 ft/hr) than MWD average rates of penetration (200 ft/hr).

MWD bed resolution is improved, compared with wireline, because of slower logging speeds. MWD formation measurements are carried outbefore significant hole enlargement occurs, resulting in data requiring correction. Also, MWD logs suffer less mud volume attenuation since tgamma sensors are housed in drill collars that typically have larger ODthan the wireline sondes. Differences are often noticed in run-by-run comparisons of wireline gamma ray logs due to centralization practice

Detected radiation, particularly the lower energy gamma rays of thoriuand uranium, is more attenuated by the thick metal housing of the MWcollar. MWD collars range from wall thicknesses of 1" to 3", while wireline gamma ray tool housings are typically 1/8” to 3/8”. Thus, the MWD measured gamma ray spectrum is biased to enhance potassiumrelative to thorium and uranium. For this reason, the MWD gamma raydata will be lower than wireline values in formations rich in thorium anduranium. After borehole correction, the two types of logs may have identical values, particularly in formations with spectral characteristics similar to the API pit.



as ze. WD s.

A wireline versus MWD gamma ray comparison is shown below from awell drilled in West Texas. Here, the corrected logs practically overlay would be expected since both logs correct for mud density and hole siSpectral biasing is negligible in this case. Note that the NaviGamma Mlog shows better resolution and character due to slower logging speed

Figure 3-2MWD/Wireline Gamma Ray Comparison Log



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Formation Resistivity

Introduction

The basic measurement used in open hole log evaluation to determinehydrocarbons are present in a formation is electrical resistance. Electrresistance is the ability to impede the flow of electric current through asubstance. The formation matrix is normally considered an ideal insulaand makes no contribution to formation conductivity. The main conducencountered in the earth's formations, is salt water. This saline water ocin the formation as free water in the pore space, water adhering to thesurface of the rock matrix, or as hydroxyl, ionically bound to clay miner


A variety of measurement principles are used by wireline resistivity tooto look at resistivity over different physical scales. A broad range of theelectromagnetic spectrum is used in resistivity tools to solve different problems. These cover a variety of tools, from the Formation MicroScanner® (FMS-a Schlumberger wireline tool) − which has a pad of tiny buttons measuring resistivity every few millimeters across the borehole, from which a pictorial image of the surface resistivity of the borehole wall may be computed, to ultra long spacing tools designed tdetect resistivity changes caused by large scale geologic features sucsalt domes or casing in adjacent wells.

Applications

All current MWD resistivity tools attempt to provide a measurement of t, the true resistivity of the rock and fluids in a reservoir, before its steadystate is affected by the presence of fluids introduced into the rock by thprocess of drilling the borehole. Wireline tools usually “see” the formatafter a stable physical equilibrium is established between the boreholefluids and the reservoir fluids. A shallow measurement is made to meathe resistivity of the rock saturated with mud filtrate (invaded zone) to enable comparison with deep measurements that are intended to meauninvaded formations.

The key to the application of resistivity logs is that it is impossible for aresistivity tool to differentiate between an increase in resistivity causedfluid changes and an increase in resistivity caused by additional rock ahence less fluid volume. Hydrocarbon fluids in rocks usually contain sowater, and the relationship between porosity, resistivity, and water



is

a,

tes, y,

l

ach ool

ues

l

saturation is key to basic resistivity analysis in the Archie equation. Thequation is the foundation of most log interpretation techniques:

Where:

Rw = interstitial water resistivity

Φ = porosity of the formation

Sw = water saturation

Rt = true formation resistivity

n = saturation exponent, normally taken to be equal to 2

a = formation constant (0.62 for sands, 1.0 for compacted formations)

m = cementation exponent (2.15 for sands, 2.0 for compacted formations)

In the above water saturation equation, the fraction including the termsm and porosity is referred to as the formation resistivity factor (F).

Key real-time uses of MWD resistivity, beyond water saturation estimainclude estimating changes in pore pressure from changes in resistivitdue to shale compaction.

Calibration

Calibration of resistivity tools is traceable to national standards for resistance. A geometric constant, the “K” factor, is used for a given toosize and sensor type to convert the resistance measured by the tool toapparent resistivity. A finite element method of computer modeling, verified by empirical measurement, is then made on the response of etool type in order to construct environmental correction charts. Some tgeometries allow direct calibration by placing fixed resistor values between the measuring electrodes of the tools, while others tools are calibrated in a large tank filled with water of known resistivity in a zero radio frequency interference environment. Details of calibration techniqare given for each sensor.


The resistivity measurement can be affected by several environmentafactors.

SwN

a

Φm-------- Rw×

Rt---------------------=



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Borehole Fluid

The resistivity of the borehole fluid may range from a non-conductive oor air, to a salt-saturated water based fluid. Different tool physics are appropriate for different fluids. Some tools require a conductive fluid (Short Normal, Focused Current) while others perform optimally in nonconductive fluids (Electromagnetic). The Baker Hughes INTEQ DPR toperforms well in all fluid types (both conductive and non-conductive media). The resistivity of the mud filtrate has an impact on tool responsinvaded zones.

Hole Size and Tool Size

Some wireline tools utilize contact pads to ensure wall contact, but thisnot applicable to propagation resistivity MWD technology. Hole size thaffects tool response, and hole washouts may cause anomalous respo

Bed Thickness

Different tool configurations produce differing responses to thin beds. Tability of a tool to resolve a bed is known as its vertical resolution. In thmajority of cases, vertical resolution and depth of investigation are converse relationships in tool design. One factor in the success of the 2MHz propagation MWD tools is a good depth of investigation with acceptable vertical resolution.

MWD and Wireline Resistivity Comparisons

MWD resistivity devices are used primarily for reconnaissance loggingpore pressure, hydrocarbon detection, and correlation purposes. One difference between MWD tools and wireline tools is formation exposurtime. For MWD, this is often an hour or less, where for wireline it is usually several days. The assumption is made that invasion on MWD is minimal, unless very high permeability are encountered. For this reaa narrower range of tools is needed to measure Rt.

Short Normal Resistivity (SNR)

This MWD service is offered commercially by Baker Hughes INTEQ anAnadrill.

During the late seventies, MWD companies looked for a resistivity measurement which could be easily made using existing technology. T16-inch short normal measurement was chosen as it was thought to hvery useful applications for pore pressure evaluation in the Gulf of MexTeleco and Anadrill constructed very similar sensors while EXLOG uselonger insulation sleeve to improve sensor response in saline muds. Tshort normal (SNR) tool has a typical operating range from 0.2 to 50



uids

t face n

d

rt on lar d so

ohm-m and provides a basic resistivity measurement in water based flwhere formation resistivity is close to mud resistivity.


This MWD tool is very similar to the equivalent wireline tool, except thathe return electrode is located on the drill collar itself, rather than a surreturn electrode. The SNR tool is a series measuring device. Formatioresistivity is measured by passing a constant current from the emittingelectrode (A) to the return electrode (N). Please refer to Figure 3-3 on page 3-10. The voltage between the measuring electrode (M) and the returnelectrode or ground (N) is measured, and formation resistivity is derivefrom Ohm’s Law:

Where:

R = apparent formation resistivity

I = current between A and N electrodes (held constant)

V = voltage measured between M and N electrodes

k = tool geometric constant

On the SNR sensor, the A and M electrodes are spaced 16 inches apaan insulated portion of the collar. The return electrode N is the drill colitself. Normally, mud temperature and mud resistivity are also measurethat environmental corrections can be made.

Short Normal Resistivity applications include:

• correlation of marker beds

• identification of casing and coring points

• identification of hydrocarbon zones

• shallow gas detection

• pore pressure determination from shale resistivity

Rk V×

I------------=



ion

s can

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unt

ted

Calibration

Calibration is carried out using an “electrode harness” into which precisresistors are inserted to simulate different formation resistivities. The system response to these resistors provides the calibration curve fromwhich formation resistivities are determined.

Service Base Calibration: A series of resistors are selected for the full range of resistivities.

Wellsite Procedures: It is not normal to perform a full calibration as described above (IS system is needed), but if required some companieprovide a wellsite calibration kit.

Short normal resistivity sensors are best suited to fresh-water muds anrelatively low formation resistivities. At high Rt/Rm ratios, the borehole and formation begin to act like parallel resistors, with an increasing amoof the measurement current flowing through relatively low resistivity borehole rather than the formation. This borehole effect can be correcfor automatically using software algorithms.

Figure 3-3MWD vs. Wireline Short Normal Resistivity



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n of n to

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e

's ”

Focused Current Resistivity (FCR)

The laterolog technique, commonly used in wireline logging, provided basis for improvements to short normal MWD. In 1987, Exploration Logging (EXLOG) introduced a laterolog-style MWD tool. This FocuseCurrent Resistivity (FCR) tool added focusing current electrodes abovand below the measurement electrode to force the measurement curredeeper into the formation.

This type of sensor was offered by EXLOG as part of its multi-sensor MWD tool. As this type of measurement is no longer available commercially with an MWD service, it is felt there is little need to dwell othis type of sensor for too long. However, the development of this typesensor was an important milestone in MWD, so some time will be givean overview of this technology.

The focused current resistivity (FCR) sensor was designed to performoptimally in salt saturated muds, providing excellent thin bed resolutionand improved response in formations where Rt is in excess of 200 ohm-m


The FCR sensor uses the same measurement principle as the guard olaterolog tool of the wireline industry. The sensor utilizes three currentemitting electrodes: two focusing and one measurement current electrCurrent is focused into the formation by forcing the voltage of both thefocusing electrodes and the measurement electrode to have the samepotential. A disc of investigating current perpendicular to the axis of thtool, is focused horizontally into the formation. The current from the focusing electrodes prevents the measurement current, from flowing vertically in the borehole. Like the SNR the FCR is a series measuringdevice. The current disc passes through the borehole fluid, then into thformation. Both output voltage and current from the measurement electrode are measured. Formation resistivity is calculated from OhmsLaw using the current and voltage of the measurement electrode. Theresistivity is converted to an apparent formation resistivity using the “Kfactor of the tool.



FCR applications include:

• quantitative Rt in salt saturated muds

• quantitative Rt in presence of nearby conductive beds

• improved thin bed delineation over SNR

• correlation of marker beds

• identification of casing and coring points

• identification of hydrocarbon zones

• pore pressure determination from shale resistivity

Figure 3-4Focused Current Resistivity



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o de m nt

tivity s ent ent

Toroidal Resistivity

Toroidal Resistivity is offered commercially by Halliburton Geodata. Anadrill/Schlumberger also use the toroidal principle in the RAB tool.

The toroidal resistivity tool is based on a proposal by JJ Arps. The tooutilizes the collar as an electrode to provide two resistivity measuremea focused lateral resistivity measurement and a trend resistivity at the bit. The tool utilizes four toroidal coils covered and protected by insulatshells. A voltage applied from the drive toroid induces an alternating current in the drillstring, which is reversed in polarity about the drive toroid. Current leaving the drillstring flows through the annulus and formation and returns to the drillstring at a point where the polarity is opposite. Essentially, induction drives a current along the collar and twsets of receivers measure this current. Tool performance in lateral modepends on the length of BHA below the receivers. As the distance frothe lower toroid to the bottom of the hole increases, the bit measuremebecomes less distinctive, and at lengths of 20 feet or more the bit resisalmost ceases to respond to changes in formation resistivity (K factor itherefore BHA dependent). With oil based muds an axial bit measuremis still possible, because of the contact of the drill bit with the formation(interstitial water). However, it should be noted that axial bit measuremwill not be possible with the bit off bottom.

Figure 3-5Toroidal Resistivity



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Electromagnetic Wave Propagation Resistivity

Electromagnetic Wave Propagation Resistivity is offered commerciallyBaker Hughes INTEQ (DPR, RNT, MPR), Anadrill/Schlumberger (CDRARC5), Sperry Sun (EWR and EWR-Phase 4), and Halliburton (CWR,SCWR).

NL Industries introduced the first 2-Mhz propagation resistivity MWD toin 1983. With one transmitter and two receivers, the EWR measuremewas effected by comparing the phase difference between the two receFor the purposes of this document, the 2-Mhz DPR tool will be used abenchmark in describing how propagation resistivity tools operate. TheBaker Hughes INTEQ Dual Propagation Resistivity (DPR) sensor alsouses a one transmitter, two receiver configuration. It has been designemaximum reliability in the MWD drilling environment and is ideally suitefor oil base and low salinity muds over a wide range of formation resistivities.

Recent developments in propagation resistivity include compensated, multi-transmitter, fully-digital electronics tools and additional, deeper reading transmission frequencies. In this regard, Baker Hughes INTEQnow offers Multiple Propagation Resistivity (MPR) and the Reservoir Navigation Tool (RNT/NaviGator service).


The Dual Propagation Resistivity (DPR) tool is a 2-Mhz electromagnetwave propagation device that provides two resistivity measurements adifferent depths of investigation. The tool contains two receiving antenwhich are spaced 27.5 and 34.5 inches (69.85 and 87.63 cm) from thesingle transmitting antenna. Additionally, a gamma ray scintillation detector is provided for lithology identification.

As the 2-Mhz radio wave travels through the formation and across thereceiving antennas, the phase difference (measured in degrees) and amplitude ratio (measured in decibels, relative to air) of the signal are measured. Resistivities are then derived using a resistivity transform.



nt he

h is s

Signal Characteristics

Although the 2-Mhz frequency of the transmitted signal remains constaas it travels through various formations, the velocity and amplitude of tsignal change with resistivity. In high resistivity formations, the 2-Mhz signal has higher velocity and is less attenuated (the signal wavelengtalso relatively long). As formation resistivities decrease, the signal slow

Figure 3-6DPR Tool Diagram



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rence 7 f a

e l is

tent occurs

y

and is increasingly attenuated (and in order to maintain constant frequethe signal wavelength shortens).

Phase Difference Measurement

The DPR sensor measures these signal changes by detecting the diffein phase, or phase shift, between the two receivers which are spaced inches (177 mm) apart. This receiver spacing is only a small fraction owavelength in high resistivity formations, resulting in small phase differences in high resistivity formations. Conversely, larger phase differences occur in low resistivity formations.

Amplitude Ratio Measurement

The transmitted DPR signal is dramatically attenuated (signal amplituddecreases) as it propagates through a conductive formation. The signaattenuated very quickly in low resistivity formations, and to a lesser exin high resistivity formations. By comparing the signal amplitude at thenear and far receivers, the DPR sensor measures the attenuation that between the two receivers. This attenuation or amplitude ratio measurement, like the phase difference measurement, is subsequentlconverted to resistivity.



DPR Signal Characteristics

Low Resistivity MediaFigure 3-7DPR Signal Characteristics



two p

eiver

.

y

s,

DPR Signal Characteristics

High Resistivity Media

Depth of Investigation

By measuring both the phase difference and attenuation between the receivers, the DPR sensor provides two resistivity measurements withdifferent depths of investigation: a shallow phase difference and a deeattenuation measurement. The lines of constant amplitude around thetransmitter are very wide, resulting in the depth of investigation of the amplitude ratio measurement being greater than the transmitter to recspacing, (namely 27.5"). In contrast, the lines of constant phase form asphere radiating from the transmitter. This results in a depth of investigation approximately equal to the transmitter to receiver spacing

Depth of investigation (DOI, expressed as a diameter) for propagationresistivity MWD measurements is strongly dependent on and positivelrelated to formation resistivity. For the DPR phase difference measurement, depth of investigation ranges from 23 inches in low resistivity formations to over 50 inches in higher resistivities. For the amplitude ratio measurement, the DOI range is roughly 40 to 60 inchedepending on resistivity.

Figure 3-8DPR Signal Characteristics



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n

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used

nce

Applications

The DPR sensor provides accurate resistivity measurements with minborehole effects over a wide range of borehole conditions and formatioresistivities.

DPR applications include all those associated with Short Normal Resistivity and:

• Resistivity measurements in oil and water-based muds

• Dual depth of investigation for invasion profiling

• Moveable hydrocarbon detection

• Excellent vertical resolution (6-inch bed delineation and 2-foot fullresolution) for thin bed evaluation in conductive beds

• Accurate Rt measurements for water saturation calculations

• Pore pressure determinations from shale resistivity

Calibration

Calibration of the DPR tool can be thought of as a three step process:temperature characterization, acquisition of base offsets, and tank measurements. To adequately compensate for the effects of downholetemperature, each sub is subjected to a thermal calibration to charactethe tool electronics under temperature. The DPR sub is placed on a noconductive rack, whereupon raw phase difference and attenuation in ameasured as the sub is slowly heated from ambient temperature to 12degC (250 degF). The sub is allowed to cool and the procedure is repeThe temperature offsets from the two characterizations must be repeawithin specified tolerances else the tool is sent for maintenance. Final temperature offsets are derived by averaging the phase and attenuatiomeasurements from both characterizations.

Base offsets are obtained next by recording raw phase difference andattenuation in air and correcting to 25 degC (77 degF). To verify the calibration, tool measurements are then acquired in a special water taknown resistivity. The temperature and base offsets are subsequently entered into the surface system computer by the field engineer and areto correct raw measurements in real-time using the MWD temperatureoutput. At the wellsite, a zero conductivity airhang measurement is performed before and after logging to ensure that tool drift occurring sishop calibration is within acceptable limits.



mud

to n

. ase nt,

y ion ok. e in

n mud

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pre-ay

nd y


Borehole Corrections

Before phase difference and attenuation values are transformed to resistivity, the measurements are first corrected for both hole size and resistivity.

Dielectric Effects

This is perhaps the most poorly understood aspect of propagation resistivity MWD services. While conductivity is the ability of a material conduct an electric charge, dielectric permittivity is the ability to store aelectrical charge. As formation composition changes, so do dielectric “constants”. Dielectric effects are often responsible for observed separations between the phase difference and attenuation resistivitiesDielectric effects tend to boost attenuation resistivities and diminish phdifference resistivities. However, given that dielectric effects are preseattenuation resistivities are affected to a greater extent.

To correct for dielectric effects, Baker Hughes INTEQ employs an empirical relationship based on a theoretical complex refractive index model (CRIM) which relates relative dielectric constant to Rt for clean reservoir rock of several different porosities. The CRIM empirical relationship has been validated with field data from several different lithologies and geographic areas. It is important to note that CRIM is designed to correct for dielectric effects in reservoir rocks only. This implies that the correction is not effectively applied in shales.

Bed Thickness Correction

In thinly bedded reservoirs, resistivity measurements may be adverselaffected by overlying and underlying lithologies. Bed thickness correctcharts are available in the Baker Hughes INTEQ interpretation chart boFor more accurate estimations of true resistivity, the resistivity responsthin beds can be enhanced using an inversion program.

Eccentricity Correction

When the tool becomes eccentered and a large contrast exists betweeresistivity and true formation resistivity, the resistivity response may become unreliable. While it is difficult to accurately quantify the amounteccentering, charts are available to help determine if the resistivity response may be affected by eccentering. The charts are intended forwell planning (e.g. BHA and mud selection) to avoid situations which mpromote an eccentered tool response.

Invasion Correction

This is perhaps the most common correction applied to both wireline aMWD resistivity data. Typically with MWD, the well is logged before an



e

tion ys

s are p . rior by

appreciable mud filtrate invasion. However, invasion corrections can bapplied by using the Baker Hughes INTEQ interpretation chart book.

MWD and Wireline DPR Comparison

The following figure is a comparison of the DPR response to the inductool response in a porous reservoir sand. MWD and wireline gamma raare plotted in track 1. The phase difference and attenuation resistivitieplotted in track 2 (2-cycle logarithmic scale), and the wireline SFL, deeand medium induction are plotted in track 3 (2-cycle logarithmic scale)Note that across the two intervals the DPR log response exhibits supevertical resolution and the induction log has been dramatically affectedinvasion. The benefits to pre-invasion MWD logging are apparent.

Figure 3-9DPR-MWD/Wireline Comparison



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Geo-steering

During the last few years, the technique of horizontal well drilling owesmuch of its success to advancements in drilling technology. Highly accurate directional survey sensors have made possible the drilling anproduction of horizontal wells. With the addition of commercial electromagnetic resistivity tools, it is now possible to navigate the wellpath in order to stay within the most productive zone. This is achievedmodeling the response of the electromagnetic resistivity tool, based oneither offset data or pilot hole resistivity logs, which are then used for precision navigation of the drill string by comparison with real-time dat

Modeling Data

The modeling of the DPR data uses a method developed by Jian Qunand refined by Hal Meyer of Baker Hughes INTEQ. This model is basedthe response of a wireline induction tool which has been modified to accommodate the geometric spacing (receiver to receiver spacing is 7inches, and receiver to transmitter spacing is 27.5 inches) of the DPR The program can compute phase angle and attenuation resistivity for multi-layered sequences, provided a measurement of true resistivity aformation dip angle is input for interbedded formations. Normally, eitheoffset or reference well log data is used as input for Rt.

A common propagation resistivity feature that is used as a navigation athe polarization horn, large resistivity peaks that are observed with bothphase and attenuation resistivity. These horns or peaks commonly occdipping bed boundaries, usually above 60 degrees, where there is a significant degree of contrast between relative Rt for the adjacent beds. It isbelieved that polarization horns are caused by a charge build up that refrom the discontinuity of the electric field across bed boundaries. This occurrence, common to 2-MHz electromagnetic resistivity devices, is caused by the operating physics of the tool and is not a measurementformation resistivity. In practice, polarization horns can be used to deteapproaching bed boundaries and, with more refinement, can even be to navigate the well path along fluid or gas contacts.

Applications

This technique is used for precision geosteering in either high-angle ohorizontal drilling applications. By making minor course corrections, anusing all the information (real-time data vs. model data), it is possible tstay within zones of interest. Because each well application is unique,fixed set of rules will apply in all cases. It is necessary to interpret dataan individual basis. Detailed modeling at the well planning stage is mandatory to properly evaluate the need for geosteering applications.



ring d 7

sand tion (i.e. irror orns

MWD Geosteering Log Example

The following model and log example illustrate an example of geosteeusing the DPR log response. The first illustration shows the dipping bemodel response. The projected well path enters the reservoir sand at 8degrees, maintains 90 degrees for 500 feet (152m) and then exits the at 93 degrees. Bed boundary detection features in the form of polarizahorns are present. Because this model follows a symmetrical well pathentry and exit across the same boundary), the bottom of the log is a mimage of the top. Due to the model’s response, including polarization hat bed boundaries, navigating the drilling assembly with the DPR tool should be effective.



) for st and ation d e

The following log example shows the actual “real-time” DPR log for thewell. MWD gamma ray is in track 1, phase difference and attenuation resistivities in track 2, and borehole inclination and well path (TVD) in track 3. As a reference, the drill bit to sensor offsets were 46 feet (14 mthe directional measurements and 31 feet (9 m) for the DPR resistivitymeasurements. Note the correlation to the modeled response. The monotable bed boundary feature are the dual polarization horns at the topbottom of the log. The separation between phase difference and attenuresistivities is not as obvious on the real-time log as it is on the modeleresponse. A characteristic drop in resistivity does occur however, on th

Figure 3-10Simulated Wellpath of 87 - 90-93°



orn r eled. )

inside of each horn. Since entry and exit occurred across the same boundary, there is symmetrical logging response. However, the dual hat the lower part of the real-time log is compressed relative to the uppehorns and the model. This is due to a steeper exit angle than that modThis is illustrated by the plot of borehole inclination and well path (TVDin track 3. The well path plot also confirms entry and exit from the reservoir sand.

Figure 3-11Phase Difference and Attenuation Resistivity Log



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into rop bed

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ined ding

ion

nal

This reservoir sand is separated into an upper high permeability memband an underlying low permeability member. One objective of the drilliassembly was to avoid drilling into the underlying low permeability member. To do this, the drilling assembly was turned upward and inclinations greater than 90 degrees were achieved (see plot of borehoinclination). Since the assembly was building upward in a slightly downward dipping formation, the drilling assembly exited the gas sand the overlying shale. This was recognized on the DPR log by an initial din resistivity which showed the drilling assembly was approaching the boundary. Attempts were made to drop angle (see plot of borehole inclination) but it wasn't enough for the drilling assembly to remain in thzone of interest (note the lag between borehole inclination and well paExit into the shale is clearly identified by the dual horns on the lower portion of the log. The premature exit from the gas sand was the combresult of a slightly higher than desired well path and the bed dip exceethe anticipated 2°/100 feet.

NaviGator

The NaviGator reservoir navigation system integrates dual frequency propagation resistivity MWD and industry leading drilling systems technology for premium geosteering applications.

The propagation resistivity sensor resides below the motor power sectand above the adjustable kick-off (AKO) sub, only 15 feet from the bit.The NaviGator power section is the industry proven Navi-Drill Mach 1 steerable mud motor. The rig floor adjustable AKO permits the directio

Figure 3-12NaviGator Tool



des

ue the ion d

,

driller to select build up rates for long and medium radius well applications.

In addition to propagation resistivity, the near-bit sensor array also includual gamma ray and inclinometer sensors. The compensated (two transmitter, two receiver) propagation resistivity sensor derives phase difference and attenuation resistivities using standard 2-MHz and uniq400 kHz transmission frequencies. The new, lower frequency extendsdepth of investigation of the tool, improving early bed boundary detectcapability for precise positioning of the wellbore. The four compensatequantitative resistivities allow accurate determination of Rt under a variety of conditions.

With an additional transmitter, the NaviGator provides compensated measurements. The above diagram shows how four raw phase (or attenuation) measurements are combined to create one compensatedborehole corrected resistivity measurement. With its two frequencies (traditional 2-MHz and new, deeper reading 400-kHz) the NaviGator

Figure 3-13NaviGator Resistivity



ion

makes 16 raw measurements which are converted to 4 quantitative, compensated resistivities.

NaviGator service benefits and applications include:

• Available for 8-1/2” to 12-1/4” hole sizes

• Fully digital electronics measure with significantly improved resolution for improved accuracy

• 400 kHz frequency offers optimal bed boundary detection for geosteering

• Dual oriented gamma ray sensors

• Near-bit inclinometer measurement while rotating and sliding

• Hardwire link between resistivity sensor and modular drill collar

• Real-time and memory-stored data acquisition

• Operates in all mud types

Multiple Propagation Resistivity (MPR)

Baker Hughes INTEQ has set a new industry benchmark for propagatresistivity logging with the introduction of Multiple Propagation Resistivity (MPR) technology. The new MPR systems provide eight quantitative resistivities by combining compensated antennas (four

Figure 3-14NaviGator Bed Boundary



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e ation t the es

tor

r the

on

9-

transmitters and two receivers) with two operating frequencies and fulldigital electronics.

The figure above illustrates the MPR 2-MHz raw measurements and thcompensation scheme that is applied to the data. The same compenstechnique is also used for the NaviGator tools, the difference being thaMPR incorporates two additional short spacing transmitters (for 32 rawvalues and 8 compensated resistivities). Compensation allows influencon the measurement, such as the deforming effects of pressure on a receiver antenna, to be canceled out. While both the MPR and NaviGatools use digital electronics (which leads to substantial accuracy improvements over the analog DPR technology), the MPR also uses arugged, collar integrated antenna design which is an improvement ovecircumferential antenna grooves of the DPR and NaviGator tools.

MPR service benefits and applications include:

• The 2-MHz phase difference resistivities offer fine vertical resolutifor defining thin beds and fluid contacts

• The unique 400-kHz frequency investigates more deeply into the formation for better estimates of Rt, improved geosteering, and greater immunity to environmental and formation effects

• Fully digital electronics measure with significantly improved resolution for improved accuracy

• 4-3/4” and 6-3/4” tools available for hole sizes between 5-7/8” and7/8”

• Rugged, collar integrated antennas

Figure 3-15MPR Data Flow



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ing

.

at tter

rce ith

ered ng

r

The i in

t, it uld ron

• Real-time and memory-stored data

• Offers eight quantitative depths of investigation

• 6-3/4” MPR is compatible with modular porosity tools

Neutron Porosity MWD Tools

Overview

Reservoir evaluation requires porosity data to quantify the volume of hydrocarbons. The Archie equation resolves water saturation from resistivity and is the basis of log analysis. A fundamental component ofArchie equation is porosity. Reservoir rock is composed of matrix and vspace. Porosity can be defined as the percentage of void space in a gvolume of rock which could be occupied by water, oil or gas.

For the purposes of this document, the Baker Hughes INTEQ ModularNeutron Porosity (MNP) tool will be used as the benchmark in describhow neutron porosity tools work. Other commercially available neutronporosity tools include the Anadrill/Schlumberger CDN (Compensated Density Neutron) tool, the Sperry Sun CNP (Compensated Neutron Porosity) tool, and the Halliburton CNEU (Compensated Neutron) tool

Measurement Theory

The concept of using neutrons to investigate the earth's formations is least fifty years old. In order for neutrons to be useful as probes of theearth’s formation, they need to interact with the target nuclei in the mathey are traversing.

In the wireline, and more recently in the MWD industry, a chemical souwhich emits neutrons as it decays is used to bombard the formation whigh energy neutrons. They are slowed down from energies of severalmillion electron volts (e.g. 4.5 MeV) to a thermal energy of 0.025 eV (electron volts) through a process called elastic collision (they are scattfrom the nuclei). The element which plays a dominant role in the slowidown (collision) process is hydrogen. In effect, the neutrons lose and transfer energy when they collide with another particle of equal mass osmaller, such as bound hydrogen nuclei in the form of water or hydrocarbon. The energy loss is equivalent to the amount of hydrogenpresent in the formation - thus it is possible to derive a hydrogen index.hydrogen index is defined as the ratio of the density of hydrogen nuclethe formation to the density of hydrogen nuclei in water. In this respecis possible to infer that porosity is a function of the number of neutronsabsorbed by hydrogen present in the porous portion of the rock. It shobe noted that hydrated clays will also show an elevated porosity. Neut



ode

ols

g it P

tools are sensitive to the presence of hydrogen but insensitive to its mof containment in the formation.

The following table summarizes the basic physical principle of neutronporosity measurement:

Neutron Classification Energy Physical ProcessFast (Source) 4.5 MeV

(average)Intermediate 100 eV to Slowing by

10 KeV Elastic CollisionSlow (Epithermal) 0.1 to

100 eVThermal

Thermal 0.025 to Diffusion 0.1 eV and

Capture

Neutron Porosity Detection and Measurement

The Baker Hughes INTEQ MNP tool uses a five Curie Americium 241 Beryllium chemical source (equivalent wireline compensated neutron touse 16 or 20 Curie sources) and two spaced point sidewall mounted scintillation type neutron detectors. The MNP is a modular sub, meanincan be added or removed from the MWD tool string at the wellsite. MNtools are available in two configurations to enable operation in differinghole sizes.



ron ion. low ith tools ght se far ount w the sity ing

ent

er

Tool diameter Fluted upsets at the detectors. 6-3/4” 7-1/2”8-1/4” 11-1/4”

From the discussion of neutron interactions, it can be seen that a neutporosity can be inferred from the hydrogen index of the subject formatThe difference between a near and a far detector is used to measure sneutrons, (epithermal or thermal) those which have had interactions wthe nuclei in the formation. The dual spaced or compensated neutron are less sensitive to environmental effects such as hole size, mud weiand mud salinity than a single thermal neutron detector. This is becauthese borehole parameters have a similar effect on both the near and detectors, and thus have little effect on the near/far detector neutron cratio. One can think of the near/far ratio as being a measurement of hoquickly the number of neutrons decreases with increasing distance fromsource, that is, a measurement of the neutron flux gradient. In low poroformations, the number of neutrons will decrease gradually with increasdistance from the source, giving a low near/far ratio. In high porosity formations, the neutron population decreases rapidly with increasing distance from the source, yielding a high near/far ratio. A transform is constructed through modeling and by empirical measurement for differhole/tool size combinations and lithologies.

Traditionally, wireline tools have used helium 3 detectors. Geiger-Mulltubes are also used in some MWD and older wireline tools to detect

Figure 3-1MNP



rs

ma

en tal

ly

ince

t uses

ross ting with nize

ich al

n of

neutron capture gamma rays. The Baker Hughes INTEQ MNP uses aninnovative method which utilizes scintillation detectors. To understandwhy this is advantageous, it is necessary to discuss how other detectofunction.

Geiger-Muller Detectors

Because of the high vibration environment associated with MWD, oneMWD company has employed G-M tubes to detect neutron capture gamrays. While this eliminates problems associated with “microphonics” sewith Helium-3 detectors, it does lead to complications with environmencorrections, especially for borehole and formation salinity effects.

Helium-3 Detectors

These are gas-filled ionization tubes filled with Helium-3. They are fairefficient and reliable in the wireline environment. However, in the high vibration drilling environment associated with MWD, the central anodewire in the He3 tube can vibrate and produce spurious noise pulses. Sthe output signal pulse of such detectors is small, vibration induced or“microphonic” noise pulses cannot easily be distinguished from actual pulses resulting from neutron detection.

Scintillation Detectors

In order to avoid problems associated with Geiger-Muller and He3 detectors, Baker Hughes INTEQ has developed a neutron detector thaa photomultiplier attached a Lithium-6 scintillator, coupled with a spectrum analyzer. Lithium-6 is a lithium isotope that has a very high capture cross section for thermal neutrons and a reasonable capture csection for epithermal neutrons. When a neutron is captured, the resullithium-6 nucleus is unstable and decays to triton and an alpha particle a combined kinetic energy of 4.78 MeV. These high energy particles iothe glass matrix and produce light flashes or scintillations. A photomultiplier tube converts the scintillations into electrical pulses whare proportional to the energy of the scintillation. The scintillation crystwill also react to natural gamma rays. Typically, energy from neutron scintillation is large compared to energy from gamma scintillation. By using a multi-channel analyzer, it is possible to distinguish the two detection types. Spectral processing enables stripping or discriminatiounwanted gamma rays.



oton n

ent

ir mber

s

Environmental Considerations

Environmental corrections are modeled using Monte Carlo Neutron Ph(MCNP) computer simulation techniques. The modeling results are theexperimentally verified.

Thus, it is possible to make real-time corrections for:

• Matrix Effect

• Mud Weight

• Annulus Effect

• Salinity

• Temperature

• Gas Effect

Through a rigorous process of theoretical and empirical modeling, it ispossible to determine how the tool responds to changes in its environmin order to correct for those environmental responses.

Calibration

Primary and secondary calibration is performed at the local MWD repaand maintenance base. This complex process subjects the tools to a nuof different porosity and environmental conditions in order to derive a primary calibration factor.

Verification

A field verifier is used at the wellsite in order to confirm that the tool haheld its shop calibration, both prior to and following runs in the hole.



rom is

in

ount

d in rtant ry lay/ sand

Gas Detection with Neutron Near/Far Count Overlay

Following is a special application example of gas detection, using propagation resistivity and neutron porosity tools.

The objective in this case was to identify and differentiate a gas sand foverlying and underlying “tight” sands. A resistivity tool cannot make thdistinction since both cases will show a high resistivity response. Typically, the combination of neutron porosity and formation density measurements would be used to identify the hydrocarbons. However, this case, the density tool configuration conflicted with the bottom-holeassembly and the anticipated performance of the planned BHA.

The neutron porosity tool and a technique known as neutron near/far coverlay was used to identify the gas. Essentially, raw counts from eachneutron detector (there are two, a near and a far detector) are acquirereal-time, normalized in a nearby water sand and plotted together. Thecurves will have a tendency to separate through a gas zone. It is impoto note that this technique only works well through zones that have veclean sands. Since the neutron porosity measurement is affected by cshale, the technique becomes less definitive as the shale content in theincreases.

Figure 3-16Gas Detection with MNP



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line

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Formation Density MWD Tools

Overview

Measuring porosity is an essential part of evaluating any formation. MWcompanies provide two primary methods of determining porosity. Onethe previously discussed neutron porosity tool and another is the denstool which applies gamma theory. Two methods are used because neimethod is capable of directly measuring porosity. Both methods obtaininferred porosity after assumptions are made about the properties of throck being measured and the fluid that is in the rock. Since rock matrixfluid content affect the two tools differently, using both methods eliminamuch of the guesswork which enables the log analyst to confidently useporosity data obtained.

Of the two porosity measurements, the density tool approach involvesfewest assumptions. Only two formation properties have to be known:matrix (rock) density and the fluid density. If these two values are knowit requires only a simple conversion to obtain a fluid filled porosity valuThe density tool provides two important measurements: the formation density and the photoelectric cross section (Pe). These two measuremcan be used with the neutron porosity measurement, resistivity measurements, and the natural gamma ray measurement to allow botquantitative and qualitative log analysis of fairly complex reservoirs. Thwe have introduced the fundamental measurement parameters that arderived from a triple combo MWD measurement system.

For the purposes of this document, the Baker Hughes INTEQ ModularDensity Lithology (MDL) tool will be used as the benchmark in describihow density tools work. Other commercially available services include Anadrill CDN (Compensated Density Neutron) tool, the Sperry Sun SF(Simultaneous Formation Density) and SLD (Stabilized Leitha Densitytools, and the Halliburton CDEN (Compensated Density) tool.

Measurement Theory

The density tool measures the formation density by using a shielded chemical source (2 Curie, Cesium 137 source, the same as most wiredensity tools) that bombards the formation with gamma rays. The formation density is a function of gamma ray count rates (and energy lemeasured at a near and far (short and long spaced) detector. The wirecounterpart of this tool is a pad contact device (containing the source adetectors) which is held in place by a spring-loaded, solenoid-activatedcaliper arm (this also provides the basic single-axis, wireline measuremof borehole diameter). It is important to minimize the thickness of mudcbetween the tool and the formation in order to obtain the most accuratestimate of formation density with minimal required environmental



ad

nt hich

rgies h an and

it .1), the

itted

ric

sity rest ent the

3.0 y f

corrections. In order to resolve this difficulty, the Teleco MDL tool achieves “pad contact” by locating the short and long spaced MDL detectors under a full gauge stabilizer. This design approximates the pconfiguration of wireline density tools.

Gamma Ray Interaction

As previously stated, formation density is a function of gamma ray courates and energy level. There are two types of gamma ray interaction ware of interest: Compton scattering and the photoelectric effect. The photoelectric effect becomes the dominant process for gamma ray enebelow 100 keV. The Pe is a result of the interaction of a gamma ray witatom in formation. In this process, the incident gamma ray is absorbedtransfers its energy to a bound electron. A Pe measurement clearly distinguishes between different elements within the formation, makingpossible to discriminate between sandstone (Pe=1.8), dolomite (Pe=3and limestone (Pe=5.1). Thus, this is an important mechanism by whichMDL tool is made sensitive to the lithology of the formation.

Moving up the gamma ray energy scale (though the actual source-emgamma rays from density tools will interact first via Compton scatteringuntil they progressively lose energy and become subject to photoelectabsorbtion), the dominant process becomes Compton scattering whichinvolves interactions of gamma rays and individual electrons. It is a process by which only part of the gamma ray energy is imparted to theelectron so that the gamma ray’s energy level is reduced with each interaction. This process is fundamental in understanding how the denmeasurement is made. This energy domain is the principle area of intefor probing the formation deeply enough to obtain a density measuremthat is between several MeV to several hundred KeV. This is also calledmean free path of radiation. For typical formation densities of 2.0 and gm/cc, the mean free path is between 4 and 20 cm. Another gamma rainteraction is pair production. Like the photoelectric process, it is one oabsorption rather than scattering. But for the purposes of density measurements this process has negligible effect and thus will not be discussed in any more detail.



his the ill/

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ount

g. ize ed

btain ool.

ll rs.

Modern wireline tools use Sodium Iodide (NaI) scintillation detectors. Tpractice has been adopted for the MWD environment and is utilized byTeleco MDL tool. This is also the preferred detection method of AnadrSchlumberger, but Sperry Sun have opted for Geiger-Muller tube detectors.

The density measurement is the density the gamma rays see on the pfrom the shielded source to the detectors. The MDL tool design insurethat, in an “in gauge” hole, the gamma rays are focused to travel only through the formation. This means that the density measured by the crate at the detectors is the true formation density. Because the tool functions like a wireline tool, it is possible to compensate for “out of gauge” conditions by using conventional “spine and rib” type processinA spine and rib algorithm has been computed for each hole size/tool scombination available. The spine is derived by plotting long/short spaccounts, and the rib is computed for differing mud cake densities and thicknesses. The modeling and empirical measurement necessary to othese so called ribs is of crucial importance to the design of the MDL t

By using state of the art technology, the MDL tool is able to make a fuspectral measurement of data from the short and long spaced detectoThis allows for a much more thorough investigation of the gamma raysobserved by the detectors than is available from more conventional

Figure 3-17Formation Density Detection and Measurement



ain

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t

o

ir mber

ne, ental

s

technology. In addition, a proprietary method is used for spectral autogstabilization.

Environmental Considerations

Environmental corrections are the result of nearly two years modeling effort using super Cray workstations and empirical modeling techniquedescribed above. The modeling results are then experimentally verifieThus, it is possible to make real time corrections for Mud Weight, MudCake Thickness, Annulus Effect and Temperature.

In the interests of timing, it is not felt necessary to dwell on this subjecother than to say that through a rigorous process of theoretical and empirical modeling, it is possible to determine how the tool responds tchanges in its environment in order to correct for those environmental responses.

Calibration

Primary and secondary calibration is performed at the local MWD repaand maintenance base. This complex process subjects the tools to a nuof materials of differing bulk densities (aluminum, magnesium, limestogranite, etc.) and hole size/tool size combinations, as well as environmconditions, in order to derive a primary calibration factor.

Verification

A field verifier is used at the wellsite in order to confirm that the tool haheld its shop calibration.



Triple Combo Applications

Directional control Thin bed/dipping bed analysis

Detailed correlation Quantitative porosity analysis

Lithology identification Lithology analysis

Coring point selection Water saturation analysis

Hydrocarbon detection Hydrocarbon type

Pore pressure analysis Moveable hydrocarbon indicator

Invasion Dynamics Oil/water contact recognition

Bed Boundary Proximity Geosteering



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s at

Data Integration at the Wellsite

Our industry today is more receptive than ever to technology which lowthe cost of hydrocarbon exploration and production. A strategic focus oBaker Hughes INTEQ is to develop and manufacture products which achieve this goal. Baker Hughes INTEQ has introduced DrillByte, a service which provides an integrated information management systemmeet the demands of drilling and engineering decision makers.

A totally integrated information service is an essential factor in successfully locating hydrocarbons while drilling exploration and development wells safely and economically. The provision of useful information in a timely manner requires the DrillByte system approachdata management through a central integrated database which can stothe engineering and geological information.

Prior to the drilling process, large volumes of offset well data, in many formats from different sources and vendors, can be easily entered intoDrillByte for pre-well planning. During drilling, essential information musbe provided at the point of need and, through the use of the Wellsite Information Transfer Specification (WITS), data from many sources cancombined.

Information output from DrillByte is in a format that can easily be interpreted so decisions can be made correctly and quickly. DrillByte ua high-resolution graphic user interface to simplify operation of the sysfor local and remote users, enabling them to concentrate on interpretaand evaluation. Sophisticated but user-friendly engineering and geologapplications are provided with the DrillByte service for processing the dto enhance the evaluation process.

The use of the UNIX operating system and information transfer standapermits data communication links, in either real-time or batch mode, toreadily established between different service contractors and the DrillBsystem during and after the drilling of the well. The use of UNIX and careful adherence to new computer standards will also permit the DrillBsoftware to be run on a wide range of hardware, with scalable performafrom a number of major vendors.

To date, EXLOG (now Baker Hughes INTEQ), has invested forty man years in the development of DrillByte. This investment will continue asnew applications are developed to meet the requirements of our clientthe wellsite and in their offices.



•Notes•



Chapter
4
n bit,

s

n and g ates

nd th

ate

ms les

Drilling Performance MWD

Definition

Drilling Performance MWD is instrumentation which provides informatiofor directional control and drilling efficiency. Drilling performance MWDprovides accurate inclination, azimuth, toolface, weight at bit, torque attemperature, and penetration rate.

This data is used to provide:

real-time directional control

reduce downtime for surveys, reduce dogleg severity

reduce risk of differential sticking

make operation more cost effective (rig day rate)

MWD now accepted as the definitive survey of record

Sensor Information

Historically, the factor which stimulated the growth of MWD in the 1970was the development of accurate real-time directional survey measurements of the wellbore position. MWD tools utilize orthogonal arrays of magnetometers and accelerometers to resolve hole inclinatiodirection. Highly accurate depth tracking systems measure the drillstrinand/or block height position and are used to calculate wellbore coordinat any given point along the well path.

MWD tools are currently used as real-time steering tools for orienting amonitoring progress when making kick off or course correction runs widownhole motors.


Wellbore position is expressed in terms of a three dimensional coordinsystem with axes aligned north/south, east/west, and vertically. The attitude of an MWD tool, in relation to the wellbore, is expressed in terof inclination, azimuth, and toolface angles. Inclination and azimuth ang

4-1

Drilling Performance MWD Baker Hughes INTEQ’s Guide to MWD

ich ng

0° eater

the uth

be rder

to

f the

the

n

rds,

tool s.

ed to

describe the orientation of the tool's long axis which coincides with thedirection of the wellbore. The toolface angle describes the angle by whthe tool, and therefore the BHA deflection device, is rotated within the loaxis of the borehole.

Inclination

Inclination is the degree of deviation from a (down) vertical orientation,is vertical and 90° is horizontal. It is also possible to measure angles grthan 90°, particularly useful in horizontal well applications.

Azimuth

Azimuth direction is the angle projected in a horizontal plane between long axis and north. For example, a hole drilled due north has an azimof zero, while a hole drilled to the west will be reported as 270 degreesazimuth. Magnetic survey tools determine azimuth with reference to magnetic north. A declination correction must be applied if azimuth is toreferenced to true north. An additional correction may be required in oto properly reference grid north.

Toolface

In directional drilling, inclination and azimuth measurements are used determine the position and direction of the wellbore. When a deflectiontool with a turbine or steerable motor is used to change the direction ohole, it is essential to know the orientation of the tool with respect to a fixed point. This orientation is known as “Toolface”

Gravity Toolface (High Side) - Hole inclination above 3 degrees

Toolface angle is generally reported with reference to the high side of hole. This angle is properly known as “gravity toolface.” This is the clockwise angle through which the reference point on the tool has beerotated from its highest point. In other words:

Toolface angle = 0° - the bent sub or steerable motor is pointing upwathe hole inclination is expected to increase with drilling, but the azimuth should remain steady.

Toolface angle = 90°- the hole azimuth should turn to the right

Toolface angle = 270°- the hole azimuth should turn to the left

Gravity toolface with respect to high side is used to enable a deflectionto control the build/drop angle and the azimuth on high inclination hole

The appropriate offset for the reference mark on the deflection tool is measured when making up the assembly and is then automatically addthe toolface angle reported. Data is output in real-time to a drill floor


Baker Hughes INTEQ’s Guide to MWD Drilling Performance MWD

on hical

s e

f

nce o d

ce

s

vity with hree

ous d,

e, it z-

l this

sured

s. In ed s on

can

mounted directional drilling display, which shows toolface data trackeda 0-360 degree dial, along with the latest inclination and azimuth. Moreadvanced service displays can also output drilling parameters and grapdisplays.

As with azimuth, the concept of “high side” or gravity toolface becomemeaningless when the hole is vertical. In these situations, an alternativmeasure of toolface is required. Magnetic survey sensors make use o“magnetic toolface” for this purpose.

Magnetic Toolface - Low Inclination Holes less than 3 degrees

Magnetic toolface is the clockwise angle through which the tool's referemark has rotated from magnetic north. The magnetic toolface is used torient the MWD tool during the initial kick off when inclination is low anhence, azimuth and high side (gravity toolface) are poorly defined. All Baker Hughes INTEQ tools automatically change from magnetic toolfato gravity toolface at hole inclinations above 3 degrees. However, this crossover point is programmable at the wellsite. Other MWD companiehave similar flexibility or maintain the 3 degree crossover convention.

Measurement Theory

Attitude of a tool can be determined by measuring the directions of graand magnetic field vectors with reference to a coordinate system fixed respect to the tool. These directions are measured by using arrays of torthogonal accelerometers and magnetometers.

When insufficient non-magnetic collars are in use, it may be advantageto disregard the measured longitudinal component of the magnetic fielsince the spurious field caused by the proximity of magnetic BHA components is closely aligned with the axis of the drillstring. In this casmay be best to measure only two axes and solve for the third axis (or axis) by using a local total magnetic field value (HTN). Baker Hughes INTEQ offers the D-RAW service for this specific application. In normause, three-axis measurements will lead to improved accuracy, althoughmay be dependent in part on attitude. This also permits use of the meafield strength as a cross-check on survey accuracy.

Measurement

Baker Hughes INTEQ MWD directional survey packages are equippedwith a single tri-axial magnetometer and three uni-axial accelerometeraddition to the measured attitude angles, the tool can transmit measurmagnetic field, magnetic dip angles, and gravity field strength as checksurvey accuracy. All Baker Hughes INTEQ directional tools can be configured to pulse raw values, so that magnetic correction algorithmsbe applied to compensate for insufficient non-magnetic collar spacing.Magnetic correction algorithms are discussed in Section II.



e

t re lled

ual eld

,

ugh s of jor

ned hes

Calibration

The primary calibration is performed in a specially constructed non-magnetic building. The calibration stand is used to orient and rotate thsensor module in each of three axes through 360°.

The calibration process is as follows:

1. Rotation around the z-axis provides x and y analysis data.

2. Rotation around the y-axis provides x and z analysis data.

3. Rotation around the x-axis provides y and z analysis data.

The data is processed to yield a set of bias, scale factor, and alignmenvalues for the six sensors. These values from different temperatures aused to build a thermal correction model. The correction model is instain the sensor package to produce thermally modeled results.

Primary Verification

Primary verification of directional accuracy includes many of the samesteps required for calibration. This verification process accurately determines the maximum allowable error in degrees for a finite set of orientations.

By analyzing total field residual errors, it is possible to determine whatresidual bias scale factor and misalignment are still inherent in the actsensors or module. The check process determines the residual total fierrors, which may include different types of aberrant sensor outputs.

Precise fixturing also allows for testing of the calibrated sensor moduleusing accurate positioning to absolute orientations for computed inclination, azimuth, and toolface.

Secondary Verification

An operational verification is performed each time the tool passes throthe local Baker Hughes INTEQ service base. The qualification consistmonitoring the measured total fields as the tool is rotated about its maaxes. Uncompensated errors in the sensors show up as sinusoidal variations. Tools which fail these qualification tests are returned to themanufacturer for repair and recalibration. In addition, all tools are returfor recalibration at six-month intervals, regardless of usage. Baker HugINTEQ service bases have the necessary equipment and software to perform complete calibrations which will assure accurate and timely readings.



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ted us.

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to the hus,

ent. r sub.

Pressure Transducer

These electromechanical devices, which convert hydraulic pressure toeither a voltage or a current, are used for downhole and surface measurement of pressure. Sensor works by the Wheatstone Bridge cona hollow expandable cylinder or diaphragm is wound with copper wire,the cylinder expands, so does the wire leading to increased resistancedecrease in current.

Temperature

This is a solid state device in the downhole electronics which is calibrato measure temperature over the range from -40 to 175 degrees Celsi

Downhole Weight on Bit / Torque on Bit

Drilling data are particularly important in deviated and horizontal boreholes. Drilling mechanics tools, such as the Baker Hughes INTEQDrilling Dynamics Gamma (DDG) tool, is able to measure downhole weight on bit, torque on bit, bending moment, gamma ray, temperaturepressure, and provide full directional control in real-time. The WOB, torque and bending moment are measured in the same sub which hasbonded strain gauges orientated in the direction of the strain to be measured - the WOB and bending moment gauges are placed parallel drill collar axis, the torque gauges are positioned at 45 degree angles. Tit is possible to discriminate axial and torsional strain and bending momThe other measurement parameters are housed in the upper transmitteA fully modular version of this tool (Modular Drilling Dynamics - MDD) is now available.

Figure 4-1Downhole Weight on Bit/Torque on Bit



that nd and

the e

d

es. ulsing The B or

Downhole Shock and Vibration

This Baker Hughes INTEQ service is termed VALID (Vibration ALert INDicator). The VALID assembly is a three-axis accelerometer system is located in the Modular Tool Controller (MTC) upper pressure plug aadapter assembly. Its purpose is to monitor and report downhole shockvibration. Through mud pulse telemetry, the driller and field service engineer will be made aware of excessive shock and vibration so that drilling conditions can be changed before bottomhole assembly damagoccurs.

Baker Hughes INTEQ, in a joint venture partnership with MELCO (Mitsubishi Heavy Industries Corporation), have developed a prototype“next generation” DDG tool. This tool is able to measure both static andynamic downhole drilling parameters based on a wellsite, operator specified initialization program. These sensors include strain gauges, accelerometers, a magnetometer, and pressure and temperature gaugThe data is processed and compressed, then, on command, sent to a por recording tool for transmission to surface and/or downhole storage. processing of data may be as simple as calculating a time average WOas demanding as performing real-time mathematical functions such ascomplex algorithms to obtain a optimal WOB, RPM, and SPM for maximum efficiency and ROP. Prototype tools were constructed and asuccessful field test and technical paper have been completed.



h

to d

ct

by d hase with d to

can , bit

Applications

Directional Drilling

Both the DDG and MDD may be used in horizontal and extended reacdrilling to provide near bit WOB, torque, and gamma data for direct indications of doglegs, torque and drag, casing wear, keyseating and fatigue failure.

Drilling Optimization

Both the DDG and MDD can provide information that allows the driller improve his drilling rate. Combination of both downhole information ansurface interpretation software can be used to improve overall drilling efficiency.

Avoidance of Drill Pipe Damage

Based on dynamic information, VALID can detect and alert the driller when the BHA is in a resonant condition.

Swab and Surge Measurement

Accurate pressure measurements recorded during tripping, used in conjunction with new models such as DEA 31, can be used to optimizesubsequent tripping speeds.

Influx Monitoring

Annulus pressure sensors, in conjunction with other sensors, can deteinflux and provide important information for subsequent well control. Itshould be noted that an independent gas influx sensor is presently in development. This type of device monitors the pressure wave createdthe Baker Hughes INTEQ MWD positive pulse transmission system ancompares the standpipe and annulus signal which are typically out of pby 180 degrees. If attenuation of the higher odd harmonics associatedthe mud pulse signal are detected in the annulus, this may be attributean influx of gas into the wellbore.

Research Functions

Used by itself, or with other systems such as the ADAMS or DynaBytedrillstring harmonics surface measurement systems, the DDG or MDDprovide the raw data for basic research in areas such as bit hydraulicswhirl, recession, eccentering and stick/slip.



•Notes•



Chapter
5
es, ,

rket

cost

ns re gh

f rn

e

leum the

st . se.

MWD Market

MWD Marketplace

The growth in the worldwide drilling markets during the last two decadcombined with advances in technology and the need for fast, accuratereliable data at the wellsite, has spawned the growth of Measurement While Drilling. Improvements in reliability and measurement capability during the late eighties has led to significant expansion. The growth mafor MWD was in long reach directional and horizontal drilling applications. The additional benefits of FEMWD to drilling performanceand efficiency was quickly recognized by operators. The integration ofperformance drilling systems is estimated to grow due to the needs of reduction through consolidation of services.

Following is a table representing total annual MWD market size in millioof US dollars. Growth rates are averaging 13 percent per year with mosizeable gains accruing following the consolidation years of 1991 throu1993.

Internationally, the UK North Sea appears to have reached a plateau osustained activity with little or moderate growth. In other parts of NortheEurope, most notably Norway, Denmark and Holland, activity levels continue to grow to some extent at the expense of intermediate wirelinlogging. This growth is also nurtured by the problematic types of wellsdrilled in these areas where MWD is used for “insurance logging” purposes. Furthermore, government bodies, such as the Norske PetroDirectorate (NPD) in Norway, have deemed that in many instances theMWD log can and is used as the definitive log of a hole section (underassumption that the log is complete, that is, no MWD failures occur).

Other growth areas such as West Africa, Latin America, the Middle Eaand, to some extent, the Far East have become the areas of increasedinterest with redeployment of MWD equipment from the Gulf of MexicoIf economic conditions are favorable, Mexico and more importantly theGulf of Campeche may gain surprising notoriety as activity levels increa

YEAR 1990 1991 1992 1993 1994 1995 1996

$MM 360 470 455 510 590 675 800+

5-1

MWD Market Baker Hughes INTEQ’s Guide to MWD

next ket

ent is y d and lds' f

ed nd ce

that for

m

all

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l on-

ions

Venezuela promises to be an area for tremendous MWD growth in the several years as multi-national oil companies have re-entered the marand PDVSA intend to dramatically increase the country’s production potential.

To a very limited extent, the newly formed Commonwealth of IndependStates (CIS) are beginning to show flurries of activity for MWD, but thisimpeded by low confidence in the market place and more importantly bguarantees of payment in hard currency. The recent social, political aneconomic upheaval in the CIS has led to a dramatic downturn in the oilgas industry and subsequent oil production. After having been the worleading oil producer in the late eighties, the industry is now in a state odramatic decline. As a result, the Ministry of Oil and Gas and associatinstitutions are very keen to form joint venture alliances with Eastern aWestern financial institutions and international oil companies. Confidenlevels are hindering progress, but as alliances continue to grow it is feltthe former Eastern Block and CIS countries could be a real “wild card”potential growth of MWD markets. The Peoples Republic of China is another intangible which, once again, is felt to have significant long tergrowth potential.

The MWD industry has recently expended significant R&D funds to smhole propagation resistivity tools (for hole sizes from 5-7/8” to 6-3/4”). Baker Hughes INTEQ, Sperry Sun, and Anadrill/Schlumberger are considered to be the dominant players in this emerging trend toward advanced FEMWD sensors for small hole applications.

The slim hole MWD market (hole sizes of 4-3/4” or less) is receiving increased attention as operators trend towards smaller and smaller hosizes. The main applications for slim hole drilling include coiled tubing,entry and short radius. While the cost savings benefit of slim and smalhole drilling can range from 25 to 75 percent, other collateral benefits include:

• Reduced environmental impact

• Smaller, more mobile drilling rigs

• Higher build rates to maximize lateral sections

The MWD market also has shown a significant demand for geosteerinMWD tools. Geosteering is the real-time interactive steering of horizonand high-angle wells using FEMWD data. Propagation resistivity MWDtools are particularly suited for this application, as pre-well modeled responses (using offset or pilot well data) can accurately predict actuareal-time MWD log responses. Hence, well path adjustments are madethe-fly to guide the wellbore to its optimum geological destination. Thegeosteering process is in stark contrast to geometrical drilling applicat


Baker Hughes INTEQ’s Guide to MWD MWD Market

which directionally steer wells to pre-determined and potentially, sub-optimal locations.


MWD Market Baker Hughes INTEQ’s Guide to MWD

•Notes•



Chapter
6
ion e 1

.

ng

Conclusion

The annual MWD market is fast approaching the round figure of $1 BillUS. MWD technology is showing tremendous potential to further invadan open hole wireline logging market, which is currently in excess of $Billion US.

Technology Will Continue to Drive the Drilling and Exploration Process

The MWD Market Will Continue its Growth by Using Technology to Increase the Efficiency and Decrease the Cost of Drilling and EvaluatiWellbores.

6-1

Conclusion Baker Hughes INTEQ’s Guide to MWD

•Notes•



Appendix
A
may

MWD Bibliography(English only, no patents)

This information was compiled from numerous literature searches and contain errors and/or omissions. Please contact the IMS with any corrections or additions to the bibliography.

PAGE SECTION

2 Overview And History

5 Data Handling

12 Drilling And Mechanical Tools

17 Drilling And Mechanical Interpretation

21 Directional Sensors

22 Directional Interpretation

25 Sensors And Interpretation

29 Formation Evaluation Tools - General

30 Mwd Interpretation - General

34 Gamma Ray Tools and Interpretation

35 Resistivity Tools And Interpretation

38 Neutron Tools And Interpretation

39 Density Tools And Interpretation

40 Radiation And Safety

40 Horizontal Holes

45 Operations

45 Pore Pressure

49 Vertical Seismic Profile

A-1

MWD Bibliography Baker Hughes INTEQ’s Guide to MWD

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Overview And History

1. Anon., 1978, State of the art, part 9, Majors do basic researcMWD: Oil & Gas Journal, v. 76, 29,no. 17 July, p. 63-64

2. Anon., 1979, Wireline services (diagraphies et methodes associees): Schlumberger Algeria Well Evaluation Conference, v.,no. Dec, p. II-1-II-30

3. Anon., 1980, MWD update: new systems operating: Oil & Gas Journal, v. 78, 11,no. 17 Mar, p. 126-148

4. Anon., 1981, MWD: making the driller's dream reality: Offshore Service Technology, v. 14, 9,no. Sept, p. 41-42,44

5. Anon., 1982, Measurement While Drilling, latest oilfield technology: Oil Gas Digest, v. 4, 11,no. 15 Nov, p. 22

6. Anon., 1983, North America. Electronic MWD (MeasuremenWhile Drilling) raises U.S. expectations: Oilman, v.,no. Aug, p. 131-132

7. Anon., 1983, Cost-saving measurement tools seek wider acceptance: Offshore Engineer, v.,no. Apr, p. 67, 69, 72-73

8. Anon., 1988, Vendors provide wide array of MWD (Measurement While Drilling) tools: Petroleum Engineer International, v. 60, 5,no. May, p. 57-58, 61

9. Anon., 1989, Manufacturers offer many choices in MWD (Measurement While Drilling) Systems: Petrolem Engineer International, v. 61, 5,no. May, p. 29-30,32

10. Arps, J. J., 1963, Continuous logging while drilling: A practicareality: SPE Annual Fall Meeting, v.,no. 6 Oct - 9 Oct, p.

11. Arps, J. L., 1979, Downhole Measurements While Drilling: A technology for the 80's: Petroleum Engineer International, v. 51, 12,no. October, p. 68, 70, 72, 74, 76, 78, 80

12. Baker, C., Fristad, P., 1986, MWD (Measurement While Drilling)-logging for the future?: IBC Technology Services Ltd. Measurement While Drilling Conference, v.,no. 6 June, p.

13. Bates, T. R., Jr., Tanguy, D. R., 1983, Downhole MeasuremeWhile Drilling: 11th World Petroleum Congress, v.,no. 28 August - 2 Sept, p.

14. Busking, B. E., 1980, Developments in Drilling Technology: 10th World Petroleum Congress, v. 3,no., p. 345-352

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15. Cheatham, J. B., Jr., 1980, Drilling technology: Present trendand future prospects: SPE of AIME Production Technology Symposium, v.,,no. 14 November - 15 November, p.

16. Coope, D. F., Hendricks, W. E., 1985, MWD (Measurement While Drilling) logs provide fast, accurate formation data: World Oil, v. 201, 2,no. 1 August, p. 46-52

17. Dempsey, P., 1987, MWD (Measurement While Drilling) technology comes of age: World Oil, v. 205, 1,no. July, p. 29-31

18. Desbrandes, R., 1989, An overview of Measurement While Drilling-Logging while drilling technology: International Well Control Symposium/Workshop, v.,no. 28 Nov - 29 Nov, p. PROC5-47

19. Evans, H. B., 1991, Evaluating differences between wireline aMWD systems: World Oil, v. v 212, n 4,no., p. p 51&

20. Fontenot, J. E., 1982, The place of technology for MeasuremWhile Drilling in the ocean margin drilling program: National Resource Council Technology for Measurement While DrillingSymposium, v.,,no. 22 Oct - 23 Oct, p. PROC 11-16

21. FP (Institut Francais Dup Petrole), 1982, Measurement WhileDrilling system (MWD): Ind Petrol Gaz-Chim, v. 50, 542,no. Apr, p. 55,57

22. Frederick, R. O., 1980, MWD: a tough nut with a bright futureDrilling , v. 41, 10,no. July, p. 42-43,45

23. Hall, G. T., 1991, Growth in the measurement-while-drilling sector continues: Oil & Gas Journal, v. v 89, n 37,no., p. p 64&

24. Holmes, A. B., 1987, New generation of MWD systems showpromise: Petroleum Engineer International, v. 59, 5,no., p. 36-44

25. Holmes, A. B., 1987, New Generation of MWD (MeasuremenWhile Drilling) systems show promise: Petroleum Engineer International, v. 59, 5,no. May, p. 36,39-40,43-44

26. Honeybourne, W., 1984, Drilling technology, future Measurement While Drilling technology will focus on two levels: Oil & Gas Journal, v. 83, 9,no. 4 Mar, p. 71-75

27. Honeybourne, W., 1985, Measurement While Drilling technology will focus on two levels: Oil & Gas Journal, v.,,no. 4 Mar, p.

28. Hutchinson, M. W., 1991, Comparisons of MWD, wireline,ancore data from a borehole test facility: Formation Evaluation and

Information Guide A-3750-500-077 Rev. A / September 1997


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Reservoir Geology Proceedings - SPE Annual Technical Conference and Exhibition, v. v omega,,no. 6 Oct, p. p 741-754

29. Jacobs, S., 1988, Approaching the frontiers of drilling technology: Petrol Management, v. 10, 1,no. Jan, p. 60-63

30. Karcher, J. C., 1935, Electrical Logging: Oil Weekly, v.,,no. 15 July, p.

31. McDonald, W. J., 1977, Four basic systems will be offered: Offshore, v. 37, 13,no. Dec, p. 92, 97-98, 103

32. McDonald, W. J., Maurer, W. C., Rehn, W. A., Williams, R., 1979, Drilling technology: assessments and future needs: Drilling , v. 40, 13,no. Oct, p. USA30-USA33

33. McDonald, W. J., Ward, C. E., 1976, Logging while drilling: asurvey of methods and priorities: 17th Annual SPWLA Logging Symposium, Paper U. TRANS 15 pp

34. Muhleman, T., Jr., Dempsey, P., 1983, High technology markanother year of drilling progress: World Oil, v. 196, 5,no. Apr, p. 133-139, 141-142, 146

35. Pollard, M., 1987, Potentials in Measurement While Drilling: 3rd Norwegian Petroleum Society, Northern Europe Drilling Conference, v.,,no. 2 Nov - 4 Nov, p.

36. Prain, K. A. R., 1986, MWD (Measurement While Drilling) asmature technology - an assessment: ICB Tech Services Ltd. Measurement While Drilling Conference, v.,,no. 6 June, p.

37. Rao, M. V., 1987, Recent advances in Measurement While Drilling: 34th Annual Southerwstern Petroleum Short CourseAssn, et al., Meeting, v.,,no. 22 Apr - 23 Apr, p. 275-281



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1. Ainsworth, C., 1978, MWD: state-of-the-art. Part 10. Gentrix venting-pulse system solves erosion, power problems: Oil & Gas Journal, v. 76, 31,no. 31 July, p. 153-154, 159, 162

2. Ainsworth, C. L., 1981, Vec-Tel survey tool an MWD telemetrsystem: Drilling Canada, v. 2, 1,no. Jan-Feb, p. 43, 45-46

3. Anon., 1978, Taking downhole measurements during drilling operations: Ocean Industry, v. 13, 3,no. March, p. 62

4. Anon., 1978, Gearhart-Owen uses negative pressure pulse inMWD: Oil & Gas Journal, v. 76, 24,no. 12 June, p. 70-72

5. Anon., 1981, Real time data processing of Measurements WDrilling: Petroleum Information No. 1559, v.,,no. 26 Nov, p. 30-31, 33

6. Arps, J. J., Arps, J. L., 1965, The subsurface telemetry problea practical solution: Journal of Petroleum Technology, v.,,no. May, p. 487-493

7. Balduc, L. R., More, H. S., 1989, Multipoint bus for MWD telemetry: International Well Control Symposium/Workshop, v.,,no. 28 Nov - 29 Nov, p. 85-97

8. Barnes, T. G., 19//?//, Transmission of torsional waves in an idealized drill string: 80th Acoustic Society of America Meeting, v.,,no., p.

9. Barnes, T. G., Kirkwood, B. R., 1972, Passbands for acoustictransmission in an idealized drill string: Acoustic Society America, v. 51, 5,no. May, p. 1606-1608

10. Barry, A., Miller, J. F., Robinson, L. H., Jr., Speers, J. M., Watkins, L. A., 1980, Exxon completes wireline drilling data telemetry system, part 1: Oil & Gas Journal, v. 78, 15,no. 14 Apr, p. 137-144, 147-148

11. Beal, A., 1983, Computers revolutionize downhole technologPetroleum News, v. 14, 1,no. April, p. 23-25

12. Besaisow, A. A., Payne, M. L., 1988, A study of excitation mechanisms and resonances inducing bottom-hole assemblyvibrations: SPE Drilling Engineer, v. 3, 1,no., p. 93-103

13. Bhagwan, J., Trofimenkoff, F. N., 1982, Electric drill stem telemetry: IEEE Trans. Geoscience Remote Sensing, v. GE-20, 2,no. April, p. 193-197



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14. Boone, D. E., 1976, Use of drilling data to cut costs: Petroleum Engineer, v. 48, 11,no. Sept, p. 70, 74, 79-80

15. Buchhold, C. W., 1982, Continuous wave mud telemetry: Natural Resources Council for MWD Symposium, v.,,no. 22 Oct - 23 Oct, p. 87-105

16. Buchholz, C. W., 1982, Continuous-wave mud telemetry: Natural Resources Council Technology for Measurement WhDrilling Symposium, v.,,no. 22 Oct - 23 Oct, p. 87-105

17. Chen, S. J., Aumann, J. T., 1985, Numerical simulation of MW(Measurement While Drilling) pressure pulse transmission: 60th Annual SPE of AIME Technology Conference, v.,,no. 22 Sept - 25 Sept, p.

18. Close, D. A., Owens, S. C., Macpherson, J. T., 1988, Measurement of BHA (Bottom Hole Assembly) vibration usinMWD (Measurement While Drilling): IADC/SPE Drilling Conference, v.,,no. 28 Feb - 2 Mar, p. 659-668

19. Cook, R. L., Nicholson, J. W., Sheppard, M. C., Westlake, W1989, First real time measurements of downhole vibrations, forces, and pressures used to monitor directional drilling operations: SPE/IACD Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 283-290

20. DeGauque, P., Grudzinski, R., 1984, Propogation of electromagnetic waves along a drill string of finite conductivitSPE of AIME, v.,,no. May, p.

21. DeGauque, P., Grudzinski, R., 1987, Propagation of electromagnetic waves along a drillstring of finite length: SPE Drilling Engineer, v. 2, 2,no. June, p. 127-134

22. DeGauque, P., Grudzinski, R., 1987, (R) Propagation of electromagnetic waves along a drillstring of finite conductivitySPE Drilling Engineer, v. 2, 2,no. June, p. 127-134

23. Denison, E. B., 1976, Making downhole measurements throumodified drill pipe: World Oil, v. 183, 5,no. Oct, p. 86-89, 94

24. Denison, E. B., 1977, Shell's high-data-rate drilling telemetrysystem passes first test: Oil & Gas Journal, v. 75, 24,no. 13 June,p. 63-66

25. Denison, E. B., 1977, High data rate drilling telemetry system52nd Annual SPE of AIME Fall Technology Conference, v.,,no., p.



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26. Denison, E. B., 1979, (R) High data-rate drilling telemetry system: Journal of Petroleum Technology, v. 31, 2,no. Feb, p. 155-163

27. Denison, E. G., 1979, High data rate telemetry system: Journal of Petroleum Technology, v. 31, 2,no. Feb, p. 155-163

28. Desbrandes, R., 1988, Status Report: MWD technology-partdata acquisition and downhole recording and processing: Petrolem Engineer International, v. 60, 9,no. Sept., p. 27-33

29. Desbrandes, R., 1988, Status Report: MWD (Measurement While Drilling): part 3: processing, display, and application: Petroleum Engineer International, v. 60, 11,no. Nov, p. 42-44, 46, 48, 51

30. Desbrandes, R., Bourgoyne, A. T., Jr., Carter, J. A., 1987, MW(Measurement While Drilling) transmission data rates can beoptimized: Petroleum Engineer International, v. 59, 6,no. June, p. 46-48, 51-52

31. Dickinson, R. T., Jones, C. M., Wagstaff, D., 1986, MWD (Measurement While Drilling) - acquisition and processing of downhole MWD and surface data during drilling: 9th Annual ASME Energy Sources Technology Conference Drilling & Production Technology Symposium, v. 4,,no. 23 Feb - 28 Feb, p99-108

32. Dickinson, R. T., Jones, C. M., Wagstaff, J. D., 1986, (R) MWDatanet - acquisition and processing of down-hole and surface data during drilling: Institute of Mining Petroleum Communications Meeting, v.,,no. 20 Jan, p. B140-B148

33. Elliott, L. R., Barolak, J. B., Coope, D. F., Hendricks, W. E., 1985, (R) Recording downhole formation data while drilling: Journal of Petroleum Technology, v. 37, 8,no. July, p. 1231-1238

34. Elliott, L. R., Barolak, J. G., Coope, D. F., 1983, Recording downhole formation data while drilling: SPE of AIME Production Technology Symposium, v.,,no. 14 Nov - 15 Nov, p.

35. Falconer, I. G., et al., 1988, Separating bit and lithology effecfrom drilling mechanics data: IADC/SPE Drilling Conference, v.,,no. 28 Feb - 2 Mar, p.

36. Foubister, D., 1984, Offshore computers: rig site computers adrilling: Oilman, v.,,no. May, p. 73-74

37. Fox, C., 1987, One megabyte memory offers downhole sensoptions: Offshore Engineer, v.,,no. April, p. 88-89



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38. Franz, D. G., 1981, Downhole recording system for MWD: 56th Annual SPE of AIME Fall Technology Conference, v.,,no. 5 Oct - 7 Oct, p.

39. Gearhart, M., Ziemer, K. A., Knight, O. M., 1981, Mud pulse MWD (Measurement While Drilling) systems report: 56th Annual SPE of AIME Fall Technology Conference, v.,,no. 5 Oct - 7 Oct, p.

40. Godbey, J. J., 1978, MWD: State of the art. part 8, system usinternal copper tubing: Oil & Gas Journal, v. 76, 27,no. 3 July, p. 72-76

41. Godbey, J. K., Gravley, W., Hawk, D. E., Patton, B. J., 1976,Development and successful testing of a continuous wave Logging-While-Drilling telemetry system: 51st Annual SPE of AIME Fall Meeting, v.,,no., p.

42. Godbey, J. K., Gravley, W., Hawk, D. E., Patton, B. J., SextonH., 1977, (R) Development and successful testing of a continuous-wave, Logging-While-Drilling telemetry system: Journal of Petroleum Technology, v. 29,,no. Oct, p. 1215-1221

43. Grange, P., 1984, MWD (Measurement While Drilling) gives more downhole data: Oilman, v.,,no. March, p. 44-45, 48

44. Grosso, D. S., Raynal, J. C., Rader, D., 1981, Report on MWexperimental downhole sensors: 56th Annual Technical Conference and Exhibition of SPE/AIME, v.,,no. 4 Oct - 7 Oct, p.

45. Grudzinski, R., Issehmann, O., 1989, Telemetry using the propogation of an electromagnetic wave along a drill pipe strinInternational Well Control Symposium/Workshop, v.,,no. 28 Nov - 29 Nov, p. 47-59

46. Guillen, G. E., Lesso, W. G., Jr., 1983, The use of weight on torque, and temperature to enhance drilling efficiency: 58th Annual SPE of AIME Technology Conference, v.,,no. 5 Oct - 8 Oct, p.

47. Holmes, A. B., 1984, Fluidic mud pulser for Measurement WhDrilling (MWD) systems: US Dept. Interior Minerals Management Service OCS Rep. No. MMS 84-0091, v.,,no., p. 45-55

48. Holmes, A. B., 1989, Fluidic pulser concepts in MWD: International Well Control Symposium/Workshop, v.,,no. 28 Nov - 29 Nov, p. 73-85



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49. Kamp, A. W., 1982, Downhole telemetry from the user's pointview: 57th Annual SPE of AIME Fall Technology Conference, v.,,no. 26 Sept - 29 Sept, p.

50. Knight, M., 1982, Mud pulse telemetry: Natural Resources Council Technology for Measurement While Drilling Symposium, v.,,no. 22 Oct - 23 Oct, p. 17-30

51. Kolker, M., Greene, A. H., Kasevich, R. S., Robertson, J. C., Grossi, M. D., 19//?//, Raytheon downhole information systemElectromagnetic Borehole Measurement While Drilling System, v.,,no., p.

52. Liang, H., Shao, Z., Cahi, Q., 1990, Processing of turbo drill rotation speed signal with an adaptive noise canceller: 65th Annual SPE Technology Conference, v.,,no. 23 Sept - 26 Sept, p413-419

53. Macpherson, J. D., Nigh, E., Muldowney, S., 1986, Boreholegeoengineering system boosts data interpretation during drilliGeobyte, v. 1, 3,no. Summer, p. 46-50, 52, 54

54. Marsh, J. L., Fraser, E. C., Holt, A. L., Jr., 1988, MeasuremeWhile Drilling mud pulse detection process: an investigation matched filter responses to simulated and real mud pressurepulses: SPE Petroleum Industry Applications of MicrocomputeSymposium, v.,,no. 27 June - 29 June, p. 119-126

55. Marsh, J. L., Fraser, E. D., Holt, A. L., Jr., 1988, ProceedingsSPE Petroleum Industry Applications of Microcomputers Symposium, v.,,no. 27 June - 29 June, p. 119-126

56. McDonald, W. J., Ward, C. E., 1975, Borehole telemetry systis key to continuous down-hole drilling measurements: Oil & Gas Journal, v. 73, 37,no. 15 Sept, p. 111-118

57. McDonald, W. J., Ward, C. E., 1978, (R) Borehole telemetry system is key to continuous down-hole drilling measurementsPetroleum Publishing Co., v.,,no., p. 96-103

58. Mettert, P. M., 19//?//, Mohole acoustic noise tests, BluewateRig No. 1: PB-167, 136, v.,,no., p.

59. Monroe, S. P., 1990, Applying digital data-encoding techniquto mud pulse telemetry: 5th SPE Petroleum Computer Conference, v.,,no. 25 June - 28 June, p. 7-16

60. Montgomery, W. C., 1982, Hardwire telemetry: Natural Resources Council Technology for Measurement While DrillinSymposium, v.,,no. 22 Oct - 23 Oct, p. 31-44



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61. Morley, A. R., 1990, Workstations for the wellsite: using newcomputer standards to implement an integrated information management system for drillers, engineers, and geologists: 5th SPE Petroleum Computer Conference, v.,,no. 25 June - 28 Junep. 51-60

62. Newton, R., Kite, R., Stone, F. A., 1980, Telemetry-MWD-thesecond-tier benefits: 55th Annual SPE of AIME Fall TechnologyConference, v.,,no. 21 Sept - 24 Sept, p.

63. Patton, B.J. et al, Development and successful testing of a continuous wave logging while drilling telemetry system, Journal of Petroleum Technology,Oct 1977, pp 1215-1221.

64. Rao, M. V., Fontenot, J. E., 1988, MWD (Measurement WhileDrilling) poised for future: part 1: many factors determine neefor real-time or recorded data: Oil & Gas Journal, v. 86, 4,no. 25 Jan., p. 65-66, 68-69

65. Raynal, J., 1981, MWD mud pulse technology (telemetrie paimpulsions hydrauliques en forage): Petroleum Technology No. 282, v.,,no. Aug-Sept, p. 9-12

66. Reed, J. P., 1984, Automated drafting of drill-hole data: Denver Petroleum Exhibition & Conference, v.,,no. 2 Oct - 3 Oct, p.

67. Richardson, G., 1980, Recent developments in mud pulse Measurement While Drilling (MWD): Oil Gas Europe Magazine, v. 6, 2,no. Autumn, p. 43-46

68. Rose, R. J., Taylor, M. R., Jantzen, R. E., 1989, Information transfer standards for well-site data: Geobyte, v. 4, 2,no. April, p. 9-13

69. Rubin, L. A., Harrison, W. H., 1987, Wireless communicationin borehole geophysics, state of the art: 2nd International Symposium on Borehole Geophysics for Min. Geotech and Groundwater Applications, v.,,no. 6 Oct - 8 Oct, p.

70. Russell, M. K., 1970, The design and development of a surfareading survey: API Prod. Div. Pacific Coast District Meeting, v.,,no. 12 May 14 May, p.

71. Santley, D. J., Ardrey, W. E., 1987, Improve MWD (Measurement While Drilling) data interpretation: Drilling , v. 48, 1,no. Jan-Feb, p. 22-24

72. Speers, J. M., Watkins, L. A., Barry, A., Miller, J. F., RobinsoL. H., Jr., 1980, New telemetry system employs unique insidewireline: World Oil, v. 190, 5,no. April, p. 57-62



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73. Spinner, T. G., Stone, F. A., 1978, Mud pulse Logging While Drilling system design, development, and demonstration: IADC/COADC Drilling Technology Conference, v.,,no. 6 Mar - 9 Mar, p. 313-327

74. Spinnler, R. F., Stone, F. A., 1978, Mud pulse logging while drilling telemetry system: design, development, and demonstrations: US Dept. Energy Rep. No. BERC/TPR, v. 78, 4,no. July, p.

75. Spinnler, R. F., Stone, F. A., 1978, Mud pulse telemetry systeused in directional drilling: 4th Annual DOE, et al., Enhanced Oil & Gas Recovery & Improved Drilling, v. 2,,no., p. H-10/1-H10/22

76. Squire, W. D., Whitehouse, H. J., 1979, A new approach to dstring acoustic telemetry: 54th Annual SPE of AIME TechnologyConference, v.,,no. 23 Sept - 26 Sept, p.

77. Taylor, K. O., Anderson, W., 1984, Electronics system speeddrilling time: Oil & Gas Journal, v. 82, 38,no. 17 Sept., p. 30, 93-96

78. Whittaker, A., Kashuba, M. J., 1987, Realtime logging: Drilling , v. 48, 1,no. Jan-Feb, p. 14-17

79. Wiltshire, M. J., 1980, Advantages of enhanced data loggingAustralian Petroleum Exploration Association, v. 20, PT 1,no., p. 103-109

80. Winther, A., Sjaaholm, A. J., Roger, D. J., 1990, Concepts ofdirectional drilling data management: 5th SPE Petroleum Computer Conference, v.,,no. 25 June - 28 June, p. 41-49

81. Wolf, S. F., Zacksenhouse, M., Arian, A., 1985, Field measurements of downhole drillstring vibrations: 60th Annual SPE of AIME Technology Conference, v.,,no. 22 Sept - 25 Sept,p.

82. Wolf, S. F., et al., 1984, Field measurement of downhole drillstring vibrations: SPE Annual Conference, v.,,no. Sept, p.

83. Shale, L, Moberley, G.T., 1992, Development of a cartridge dtransmission system for use with air drilling motor, Proceedings of the SPE Drilling Conference: New Orleans, LA, Feb 18-21, pp 603-610.



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1. Anon, 1975, Your downhole motor: hey, where'd it go: Drilling , v. 36, 12,no. Sept, p. 120-124

2. Anon., 1981, Murchison turns out a speedy production profiledrillers slice weeks off budgeted well time: Noroil, v. 9, 11,no. Nov, p. 61, 64

3. Anon., 1983, Second-generation MWD (Measurement While Drilling) tool passes field tests: Oil & Gas Journal, v. 81, 8,no. 21 Feb, p. 84-90

4. Anon., 1988, ARCO drills high angle wells in Bima Field: Offshore, v. 48, 2,no. Feb, p. 27-28

5. Anon., 19//?//, Project mohole-phase 2 stage "A" report engineering design and testng work pertaining to (1) special 82 in wire-line coring turbodrill (2) tests of: PB-169,025, v.,,no., p.

6. Bannerman, J. S., 1990, Walk rate prediction on Alwyn NorthField by means of data analysis and 3D computer model: SPE Europe Petroleum Conference (EUROPEC 90), v.,,no. 21 Oct - 24 Oct, p. 471-476

7. Bardin, C. A., 1987, Remote-controlled bent sub aids directiodrilling by allowing bend-angle change: Oil & Gas Journal, v. 87, 5,no. 30 Jan, p. 76, 78-80

8. Bayne, R., 1986, Navigation drilling technology progresses: Drilling , v. 47, 11,no. Nov-Dec, p. 12, 14-16, 18

9. Belaskie, J. P., 1988, Spudding a vertical hole in deep water using MWD (Measurement While Drilling) surveys: IADC/SPE Drilling Conference, v.,,no. 28 Feb - 2 Mar, p. 333-339

10. Besaisow, A. A., Ng, F. W., Close, D. A., 1990, Application oADAMS (Advanced Drillstring Analysis and Measurement System: IADC/SPE Drilling Conference, v.,,no. 27 Feb - 2 Mar, p. 717-722

11. Bierschwale, H., Ridley, R., 1988, Steerable systems adds precision to Gulf drilling: Oil & Gas Journal, v. 86, 18,no. 2 May, p. 42-44, 47-48, 50

12. Bitto, R., 1987, Systems approach speeds offshore drilling operations: Ocean Industry, v. 22, 7,no. July, p. 25-27

13. Boulet, J. G., Morin, P. E., Laval, E. J., Bosch, J. R., 1983, Tnew remote-controlled and multiangle bent sub (telepilote) fo



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drilling trajectory control and corrections: IADC/SPE Drilling Conference, v.,,no. 20 Feb - 23 Feb, p. 233-240

14. Bourgoyne, A. T., Desbrandes, R., 1986, Integration of MWD(Measurement While Drilling), well control technologies: Offshore, v. 46, 9,no. Sept, p. 49-50, 52

15. Bruce, G. H., 1982, Current and future detection needs in wecontrol: Natural Resources Council Technology for Measurement While Drilling Symposium, v.,,no. 22 Oct - 23 Oct, p. 45-61

16. Bryant, T. M., Grosso, D. S., Wallace, S. N., 1991, Gas-influxdetection with MWD technology: SPE Drilling Engineering, v. v6, n4,no. Dec, p. 273-278

17. Clayer, F., Vandiver, J. K., Lee, H. Y., 1990, The effect of surface and downhole boundary conditions on the vibration odrillstrings: 65th Annual SPE Technology Conference, v.,,no. 23 Sept - 26 Sept, p. 183-196

18. Close, D. A., Owens, S. C., Macpherson, J. T., 1988, Measurement of BHA (Bottom Hole Assembly) vibration usinMWD (Measurement While Drilling): IADC/SPE Drilling Conference, v.,,no. 28 Feb - 2 Mar, p. 659-668

19. De Lange, J. I., Darling, T. J., 1988, Improved detectability oblowing wells: IADC/SPE Drilling Conference, v.,,no. 28 Feb - 2 Mar, p. 621-628

20. DeLucia, F. V., 1989, Benefits, limitations, and applicability osteerable system drilling: SPE/IADC Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 325-332

21. Desbrandes, R., Morin, P., 1982, Advances in remote controdrilling: Canadian Petroleum Technology, v. 21, 6,no. Nov-Dec, p. 78-90

22. Duddleson, B., Arnold, M., McCann, D., 1990, Early detectioof drillstring washouts reduces fishing jobs: World Oil, v. 211, 4,no. Oct, p. 43-47

23. Easterling, D., Jones, W., 1987, Steerable system optimizes drilling time: Offshore, v. 47, 8,no. Aug, p. 120, 122

24. Engler, B. P., 1982, Instrumentation for the cornering water jdrill: 8th US Dept. of Energy Underground Coal Conversion Symposium, v.,,no. 15 Aug - 19 Aug, p. 93-102

25. Falconer, I. G., Burgess, T. M., Wolfenberger, E., 1986, Drillitechnology report. MWD (Measurement While Drilling)



n

.,

as

bit,

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interpretation tracks bit wear: Oil & Gas Journal, v. 86, 6,no. 10 Feb, p. 55-59

26. Falconer, I. G., Normore, D., 1987, Well site applications of aMWD (Measurement While Drilling) bit efficiency model: SPE Annual Conference, v.,,no. July, p.

27. Fontenot, J. E., Rao, M. V., 1988, MWD (Measurement WhileDrilling) poised for future: part 4: MWD aids vital drilling decisions: Oil & Gas Journal, v. 86, 11,no. 14 Mar, p. 60, 62-65

28. Goebel, E. D., Coveney, R. M., Jr., Zeller, E. J., Angino, E. EDreschhoff, G. A. M., 1985, Gas monitoring during drilling substantiates hydrogen occurrence and eliminates corrosion source: Annual AAPG-SEPM-EMD-DPA Convention, v.,,no. 24 Mar - 27 Mar, p.

29. Guillen, G. E., Lesso, W. G., Jr., 1983, The use of weight on torque, and temperature to enhance drilling efficiency: 58th Annual SPE of AIME Technology Conference, v.,,no. 5 Oct - 8 Oct, p.

30. Hearn, E., 1984, How operators can improve performance ofMeasurement While Drilling systems: Oil & Gas Journal, v. 82, 44,no. 29 Oct, p. 80-81

31. Karlsson, H., 1987, Drilling systems increase efficiency: Offshore, v. 47, 4,no. April, p. 31-34

32. Karlsson, H., Krueger, B., Brassfield, T., 1985, Performance drilling optimization: IADC/SPE Drilling Conference, v.,,no. 5 Mar - 8 Mar, p. 439-452

33. Kelly, A. O., 1989, A computer assisted well control safety system for deep ocean well control: International Well Control Symposium/Workshop, v., Baton Rouge, LA,no. 28 Nov - 29 Nov, p.

34. Kelly, O. A., Casariego, V., 1989, Computer-assisted Measurement-While-Drilling (MWD) for deep ocean well control: International Well Control Symposium/Workshop, v.,,no. 28 Nov - 29 Nov, p. 231-249

35. Kent, W. H., Mitchell, P. G., Row, R. V., 1980, Geothermal down-well instrumentation (during drilling). Final report: Energy Resources Abstract, v. 5, 9,no. 15 May, p. 1458

36. Knox, D. J. W., Milne, J. M., 1987, Measurement While Drillintool performance in the North Sea: SPE Offshore Europe Conference, v.,,no. 8 Sept - 11 Sept, p.



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37. Knox, D. W. J., Milne, J. M., 1987, Measurement While Drillintool performance: Offshore Europe `87 Conference, v.,,no. Sept, p.

38. Koskie, E. T., Jr., Slage, P., Lesso, W., Jr., 1988, Monitoring MWD (Measurement While Drilling) torque improved PDC (Polycrystalline diamond compact) bit penetration rates: World Oil, v. 207, 4,no. Oct, p. 62-63, 65, 67

39. Lamb, J. C., 1986, Measurement While Drilling - an operatorexperience: IBC Technology Services Ltd. Measurement WhileDrilling Conference, v.,,no. 6 June, p.

40. LeBlanc, L., 1987, Integrated data aids rig management: Offshore, v. 47, 4,no. Apr, p. 36-38

41. Leraand, F., Wright, J. W., Zachery, M., Thompson, B., 1990Relief well planning and drilling for a North Sea underground blowout: 65th Annual SPE Technology Conference, v.,,no. 23 Sept - 26 Sept, p. 183-196

42. McKown, G. K., 1989, Drillstring design optimization for highangle wells: SPE/IADC Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 275-282

43. Mitchell, M. F., Allamon, J. P., Daugherty, W. T., Beaton, C. LSprague, J. D., 1990, Conoco optimizes deepwater template drilling: Petroleum Engineer International, v. 62, 9,no. Sept, p. 16-17, 21-23

44. Monti, R. L., Huchital, J. S., Burgess, T. M., 1987, Optimizeddrilling-closing the loop: 12th World Petroleum Congress, v.,,no. 26 Apr - 1 May, p. 131-142

45. Moore, O. T., Zamora, M., 1974, Use of the DC-exponent to minimize drilling costs in the Delaware Basin: 21st Annual Southwestern Petroleum Short Course Assn., et al., Meeting, v.,,no., p. 29-33

46. Nakken, E. I., Baltzerson, O., 1990, Characteristics of drill bitgenerated noise: 31st Annual SPWLA Logging Symposium, v.,,no. 24 June - 27 June, p.

47. Newton, R., Stone, F. A., Kite, R. L., 1980, MWD study says system save trips, time: Offshore, v. 40, 14,no. Dec, p. 88, 90, 9296, 98, 102

48. Sawolo, N., 1988, Utilization in the Attaka Field of a new fourcomponent drilling system: 7th SPE, et al., Offshore South EasAsia Conference, v.,,no. 2 Feb - 5 Feb, p. 82-97



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49. Shirey, D. L., Lover, S. L., 1982, Development testing of a cornering water jet drill: 8th US Dept. of Energy Underground Coal Conversion Symposium, v.,,no. 15 Aug - 19 Aug, p. 123-142

50. Stanton, C., 1974, Steering to success: Engineering, v. 214, 10,no. Oct, p. 808-812

51. Sutcliffe, B., Sim, D., 1991, Drilling optimized by monitoring BHA dynamics with MWD: Oil & Gas Journal, v. v 89, n 12,no., p. p 41-45

52. Sutcliffe, B., Simm, D., 1991, Drilling optimized by monitoringBHA dynamic with MWD: Oil & Gas Journal, v. v 89, n 12,no. 25 Mar, p. p 41-45

53. Taylor, M. R., Morley, A. R., 1989, Prevention or cure? Kick avoidance and detection using MWD in integrated wellsite information management system: International Well Control Symposium/Workshop, v., Baton Rouge, LA,no. 28 Nov - 29 Nov, p.

54. Thiery, J. R., 1978, Flexodrill monitors borehole continuouslyOil & Gas Journal, v. 76, 20,no., p. 68-71

55. Ting, S. L., 1989, Planning and drilling the record breaking loreach well Cormorant A-13: 3rd Annual IBC Technology Services Ltd. Offshore Drilling Technology Conference, v.,,no. 29 Nov - 30 Nov, p.

56. Traynor, B. V., Jr., 1978, Electrodrill demonstration shows promise: Oil & Gas Journal, v. 76, 16,no., p. 108-129

57. Tsai, C. R., 1992, Improve drilling safety and efficiency with MWD sensors: Proceedings of the International Meeting on Petroleum Engineering, v.,,no. 24 Mar, p. 571-578

58. Whitten, R. G., Petrey, P. A., III, 1989, Unleashing the powersteerable systems: SPE/IADC Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 325-332



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Drilling And Mechanical Interpretation

1. Bates, T. R., Jr., Martin, C. A., 19//?//, Drilling technology report. Multisensor Measurement While Drilling tool improvedrilling economics: , v.,,no., p.

2. Belaskie, J. P., Choo, D. K., Dunn, M. S., 1990, Distinct applications of MWD (Measurement While Drilling) weight-onbit and torque: IADC/SPE Drilling Conference, v.,,no. 27 Feb - 2 Mar, p. 467-476

3. Bleakley, W. B., 1982, How Conoco cuts Murchison drilling time: Petroleum Engineer, v. 54, 2,no. Feb, p. 46, 48-49

4. Boatman, W. A., 1967, Measuring and using shale density toin drilling wells in high-pressure areas: Journal of Petroleum Technology, v.,,no. Nov, p. 1423-1429

5. Boone, D. E., 1974, Analysis of drilling strengths in evaporiterocks: SPE of AIME Deep Drilling & Production Symposium, v.,,no., p. 91-102

6. Booth, J. E., Hebert, J. W., II, 1989, Support of drilling operations using a central computer and communications facwith real-time MWD (Measurement While Drilling) capability and networked personal computers: SPE Petroleum Computer Conference, v.,,no. 25 June - 28 June, p. 71-77

7. Burgess, T. M., Lesso, W. G., Jr., 1985, Measuring the wear tooth bits using MWD torque and weight-on-bit: SPE/IADC Drilling Conference, v.,,no. 6 Mar - 8 Mar, p.

8. Clary, M. M., Stafford, T. W., III, 1987, MWD (Measurement While Drilling) performance and economic benefits in the Zu horizontal drilling program: SPE/IADC Drilling Conference, v.,,no. 15 Mar - 18 Mar, p. 1065-1076

9. Cushing, R., Starkey, A. A., 1989, Fracture identification usinMWD downhole weight and torque measurements: SPE California Region Meeting, v.,,no. 5 Apr - 7 Apr, p.

10. DeBruijn, H. J., Kemp, A. J., Van Dongen, J. C. M., 1984, Thuse of MWD (Measurement While Drilling) for turbodrill performance optimisation as a means to improve rate of penetration: SPE of AIME Europe Petroleum Conference, v.,,no. 22 Oct - 24 Oct, p. 353-360

11. Desbrandes, R., Bourgoyne, A. T., Jr., 1987, MWD (Measurement While Drilling) monitoring of gas kicks ensures



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safer drilling: Petroleum Engineer International, v. 59, 7,no. July, p. 46-52

12. Falconer, I. G., Burgess, T. M., Wolfenberger, E., 1986, Drillitechnology report. MWD (Measurement While Drilling) interpretation tracks bit wear: Oil & Gas Journal, v. 86, 6,no. 10 Feb, p. 55-59

13. Falconer, I. G., Normore, D., 1987, MWD (Measurement WhDrilling) bit-efficiency model provides real-time answers: Oil & Gas Journal, v. 85, 43,no. 26 Oct, p. 40-42, 44, 47-48

14. Fear, M. J., Normann, T. A., 1989, Realtime interpretation of performance and formation: Noroil, v. 17, 3,no. March, p. 29-31

15. Fleming, N. H., Ronaldi, R., Bruce, S., Haryanto, J., 1990, Thapplication of "mechanical" borehole stability theory to development well planning: IADC/SPE Drilling Conference, v.,,no. 27 Feb - 2 Mar, p. 283-289

16. Fontenot, J. E., Rao, M. V., 1988, MWD (Measurement WhileDrilling) poised for future: conclusion: Measurement While Drilling essential to drilling: Oil & Gas Journal, v. 86, 13,no. 28 Mar, p. 52-55, 58

17. Fontenot, J. E., Rao, M. V., 1988, MWD (Measurement WhileDrilling) poised for future: part 3: MWD can improve well safety, control: Oil & Gas Journal, v. 86, 7,no. 15 Feb, p. 40-4144-46, 48

18. Griffin, W. H., Keith, F. A. J., 1982, MWD (Measurement WhilDrilling) North Sea Fild use, Aug. 1978-Feb. 1979 (with 1982update): Journal of Petroleum Technology, v. 34, 12,no. Dec, p. 2888-2898

19. Haciislamoglu, M., 1990, Mud shear rate distribution st the wof a deviated well and its effect on filtration: LSU-MWD Symposium, v.,,no. 26 Feb 27 Feb, p. 137-147

20. Hansen, E., 1989, Extended reach drilling in the Valhall Field4th Norwegian Petroleum Society N. Europe Drilling Conference, v.,,no. 30 Oct - 1 Nov, p.

21. Hytten, N., Havrevold, L., Parigot, P., 1991, Getting more outdrilling data by analysis-while-drilling: Offshore Europe 91 - Prodeedings, v.,,no. 3 Sep, p. p 219-226

22. Johancsik, C., Leraand, A. E., Petovello, B. G., Gust, D. A., Smith, B. W., 1984, Application of Measurement While Drillingin a shallow, highly deviated drilling program: 35th Annual Petroleum Society of CIM & Canadian Assn. Drilling



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Engineering Recovery & Beyond Technology Meeting, v.,,no. 10 June - 13 June, p. 521-531

23. Lesso, W. G., Jr., Falconer, I. G., 1986, Drilling interpretationfrom MWD (Measurement While Drilling) data: IBC Technology Services Ltd. Measurement While Drilling Conference, v.,,no. 6 June, p.

24. Lillelokken, N. H., 1990, Drilling optimization on Gyda development project: a case study: 22nd Annual SPE, et al., Offshore Technology Conference (OTC`90), v.,,no. 7 May - 10 May, p. 251-260

25. Martin, C. A., 1986, Wellsite applications of integrated MWD (Measurement While Drilling) and Wellsite data: IADC/SPE Drilling Conference, v.,,no. 10 Feb - 12 Feb, p.

26. Maurer, W. C., 1977, Drilling R & D underway in the United States: IADC Drilling Technology Conference, v.,,no. 16 Mar - 18 Mar, p.

27. Moore, S. D., 1986, MWD (Measurement While Drilling) toolsimprove drilling performance: Petroleum Engineer International, v. 58, 2,no. Feb, p. 49, 51-52

28. Pidcock, G., Daudey, J., 1988, Gulf Canada improves drillingwith MWD (Measurement While Drilling) technique: Petroleum Engineer International, v. 60, 9,no. Sept, p. 16, 19-22, 24

29. Rewcastel, S., 1989, MWD (Measurement While Drilling) interpretation for monitory bit wear and drillability: 4th Norwegian Petroleum Society N. Europe Drilling Conference, v.,,no. 30 Oct - 1 Nov, p.

30. Ryan, D. M., 1987, A model for measuring the effectiveness MWD (Measurement While Drilling) systems: SPE/IADC Drilling Conference, v.,,no. 15 Mar - 18 Mar, p. 111-117

31. Sawolo, N., 1988, Utilization in the Attaka Field of a new fourcomponent drilling system: 7th SPE, et al., Offshore South EasAsia Conference, v.,,no. 2 Feb - 5 Feb, p. 82-97

32. Teige, T. G., Undersrud, E., Rees, M., 1984, MWD (Measurement While Drilling): a case study in applying new technology in Norwegian Block 34/10: SPE of AIME Europe Petroleum Conference, v.,,no. 22 Oct - 24 Oct, p. 373-381

33. Vandiver, J. K., et al., 1989, Case studies of the bending vibration and whirling motion of drill collars: SPE/IADC Drilling Conference, v.,,no. 28 Feb - 3 Mar, p.



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34. Whitten, R. G., 1987, Application of side-force analysis and MWD (Measurement While Drilling) to reduce drilling cost: SPE/IADC Drilling Conference, v.,,no. 15 Mar - 18 Mar, p. 549-554

35. Zoeller, W. A., 1974, Rock properties determined from drillingresponse: Petroleum Engineer, v. 46, 7,no. July, p. 34-35, 38, 4044

36. Zoeller, W. A., 1974, Analysis of rock properties from drilling response: 15th Annual SPWLA Logging Symposium, v.,,no., p.

37. Kuru, E., Wojtanowicz, A.K., 1992, A theoretical method for detecting insitu PDC bit dull and lithology change: Journal of Canadian Petroleum Technology, v31, n7, Sep, pp 35-40

38. Fay, H., 1992, An easy-to-use method for tracking rock-bit wewhile drilling, Revue De L Institut Francais Du Petrole: v 47, n 4, Jul-Aug, pp 465-478

39. Jogi, P.N., Zoeller, W.A., 1992, Application of a new drilling model for evaluating formation and downhole drilling conditions, Proceedings of the Petroleum Computer Conferenc: Houston, TX, July 19-22, SPE 24452, pp 275-286.

40. Afinsen, B.T., Rommetveit, R., Sensitivity of early kick detection parameters in full-scale gas kick experiments with oand water based drilling muds, Proceedings of the SPE Drilling Conference: New Orleans, LA, Feb 18-21, pp775-782

41. Jardine, S.I., McCann, D.P., Barber, S.S., 1992, Advanced system for the early detection of sticking pipe, Proceedings of the SPE Drilling Conference: New Orleans, LA, Feb 18-21, pp 659-667.

42. Cheatham, C.A., Comeaux, B.C., Martin, C.J., 1992, Generaguidelines for predicting fatique life of MWD tools, Proceedings of the SPE Drilling Conference: New Orleans, LA, Feb 18-21, pp 591-601

43. Rewcastle, S.C., Burgess, T.M., 1992, Real-time shock measurements increase drilling efficience and improve MWDreliability, Proceedings of the SPE Drilling Conference: New Orleans, LA, Feb 18-21, pp 433-442

44. Shepard, J.S., 1992, Extended drillpipe life with tighter specifications, Proceedings of the SPE Drilling Conference: New Orleans, LA, Feb 18-21, pp 27-34.

45. Cassidy, S.D., 1992, Solutions to problems drilling a high-pressure, high-temperature well, Drilling Proceedings - SPE



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Annual Conferecnce and Exhibition, Washington, DC, Oct 4-7delta, SPE 24603, pp 613-622.

Directional Sensors

1. Anon., 1975, New tool accelerates directional surveying: World Oil, v. 181, 5,no. Oct, p. 91-92, 95

2. Anon., 1981, Directional Measurement While Drilling explained: Offshore Service Technology, v. 14, 10,no. Oct, p. 17,20-21

3. Brindley, C. P., 1988, Continuous orientation measurement systems mimimize drilling risk during coring operations: IADC/SPE Drilling Conference, v.,,no. 28 Feb - 2 Mar, p. 341-346

4. De Lange, J. I., et al., 19//?//, Accurate surveying: an operatopoint of view: IADC/SPE Drilling Conference, v.,,no. 28 Feb - 2 Mar, p. 325-332

5. Field, L. J., Ainsworth, C. L., 1981, Automatic bit locator usesmud pulse telemetry for wellbore steering: Oil & Gas Journal, v. 79, 17,no. 27 Apr, p. 155-162, 167

6. Gibbons, F. L., Hense, U., 1987, A three-axis laser gyro systefor borehole wireline surveying: SPE Annual Fall Meeting, v.,,no. 27 Sept - 30 Sept, p.

7. Harrell, J. W., Dickinson, R. T., Wiley, W. W., III, 1988, The application of a modular Measurement While Drilling system fdirectional control and formation evaluation in horizontal wellsSPE Petroleum Engineering International Meeting, v.,,no. 1 Nov - 4 Nov, p. 541-562

8. Hoover, D., Recht, M., 1980, Eastman develops wireless surtool: Oil & Gas Journal, v. 78, 26,no. 30 June, p. 80-82

9. Knight, O. M., 1983, Toolpusher logging - an aid in advanceddirectinal drilling programs: 1st Norwegian Petroleum Society NEurope Drilling Conference, v.,,no. 24 Oct - 26 Oct, p.

10. Kopecki, D. S., 1989, Developing complete resistance to strecorrosion cracking in nonmagnetic drilling tools: 64th Annual SPE Technology Conference, v.,,no. 8 Oct - 11 Oct, p. 299-303

11. Marshall, G. D., 1975, Surveying and steering whle drilling wa mud motor: Petroleum Engineer, v. 47, 7,no. July, p. 34,36,38

12. Marshall, G. D., 1976, Survey steering tool: the ultimate for saving rig time: SPE of AIME Rocky Mountain Region Meeting, v.,,no., p.



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13. McDonald, W. J., 1978, MWD: State of the art, part 1, MWD looks best for directional work and drilling efficiency: Oil & Gas Journal, v. 76, 13,no. 27 Mar, p. 141-147

14. McDonald, W. J., 1980, MWD: State of the art, part 1. MWD looks best for directional work and drilling efficiency: Oil & Gas Journal, v. 76, 14,no. 3 Apr, p. 115-116

15. Millheim, K. K., 1981, Directional control with regard to telemetry: Natural Resources Council Technology for Measurement While Drilling Symposium, v.,,no. 22 Oct - 23 Oct, p. 147-156

16. Roberts, W. F., Johnson, H. A., 1978, Systems available for measuring hole direction: Oil & Gas Journal, v.,,no. 20 May, p. 68-70

17. Russell, A. W., Roesler, R. F., 1985, Reduction of nonmagnedrill collar length through magnetic azimuth correction technique: IADC/SPE Drilling Conference, v.,,no. 5 Mar - 8 Mar, p. 463-470

18. Salerno, G., 1985, Changing directions - a look at the directiodrilling market: Drilling , v. 47, 1,no. Nov, p. 18-22, 45-46

19. Thometz, T. G., 1976, Determining nonmagnetic survey collarequirements: World Oil, v. 182, 6,no. May, p. 79-80

20. Wesenberg, D. L., Polito, J., 1987, A new innovation in directional only MWD (Measurement While Drilling) systems:SPE/IADC Drilling Conference, v.,,no. 15 Mar - 18 Mar, p. 95-102

Directional Interpretation

1. Alixant, J. L., 1989, Improved directional interpretation methoInternational Well Control Symposium/Workshop, v.,,no. 28 Nov - 29 Nov, p. 197-231

2. Alixant, J.-L., et al., 1989, Increasing directional accuracy at ncost: Submitted to SPE Annual Conference, v.,,no. 8 Oct - 11 Oct, p.

3. Bakke, S., 1986, Directional drilling: the state of the art: Petroleum Review, v. 40, 470,no. Mar, p. 48-49, 51, 53, 55-56

4. Cooks, R. L., Nicholson, J. W., Sheppard, M. C., Westlake, W1989, First real time measurement of downhole vibrations, forces, and pressures used to monitor directional drilling operations: , v.,,no. 28 Feb - 3 Mar, p.



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5. De Lange, J. I., et al., 1988, Accurate surveying: an operatorpoint of view: IADC/SPE Drilling Conference, v. 31, 2,no., p. 155-163

6. Deo, B. J. S., 1984, An analysis of the angles of rotation andazimuth using M.W.D. (Measurement While Drilling): SPE of AIME, v.,,no. May, p.

7. Gabris, P. M., Hansen, R. R., Bartrina, J., 1988, A field comparison of the directional accuracy of MWD (MeasuremeWhile Drilling) in comparison with six other survey tools: IADC/SPE Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 669-676

8. Gaudin, D. B., Beasley, J. C., 1991, Comparison of MWD anwireline steering tool guidance systems in horizontal drilling: Drilling proceedings - SPE Annual Technical Conference andExhibition, v. v delta,,no. 6 Oct, p. p 7-18

9. Gearhart, M., 1981, Field results using Measurement While Drilling directional systems in Long Beach, CA, part 1: Australian Petroleum Exploration Association, v. 21,,no., p. 213-221

10. Gearhart, M., 1981, Field results using Measurement While Drilling (MWD directional systems in Long Beach, CA: 28th Annual Southwestern Petroleum Short Course, v.,,no. 23 Apr - 24 Apr, p. 26-37

11. Grinrod, S. J., Wolff, J. M., 1983, Calculation of NMDC lengthrequired for various latitudes developed from field measuremeof drill string magnetization: IADC/SPE Drilling Conference, v.,,no. 20 Feb, p.

12. Gust, D. A., 1987, An evaluation of survey accuracy at Cold Lake: Canadian Petroleum Technology, v. 26, 2,no. March-April, p. 52-56

13. Holmes, A., 1987, A method to analyze directional surveyingaccuracy: 62nd Annual SPE Technology Conference, v.,,no. 27 Sept - 30, p.

14. Johancski, C. A., Smith, B. W., Leraand, A. E., Petovello, B. Gust, D. A., 1985, (R) Application of Measurement While Drilling in a shallow, highly deviated drilling program: Canadian Petroleum Technology, v. 24, 5,no. Sept-Oct, p. 37-42

15. Legros, F. W., Jr., Martin, C. A., 1985, Applications of Measurement While Drilling (MWD); developments of the EasBreaks Field, Offshore Texas: IADC/SPE Drilling Conference, v.,,no. 5 Mar - 9 Mar, p. 545-553



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16. Mitrou, T. J., Stone, F. A., McCarter, M. L., Buss, B., 19//?//, (Comparison of magnetic single-shot instruments with a directional MWD (Measurement While Drilling) system: SPE Drilling Engineer, v. 1, 2,no. April, p. 163-168

17. Morris, F. J., et al., 1977, A new method of determining rangeand direction from a relief well to a blowout well: SPE Annual Fall Meeting, v.,,no. 9 Oct - 12 Oct, p.

18. Navarro, A. R., Yalcin, O., 1990, Determining the drillability ohigh-angle, large displacement wells by analyzing the effectsdog leg severity: SPE East Region Conference, v.,,no. 31 Oct - 2 Nov, p. 161-166

19. Newton, R., Kite, R. L., Stone, F. A., 1981, A case study comparison of wells drilled with and without MWD directionalsurveys on the Claymore Platform in the North Sea: Petroleum Technology, v. 282,,no. Aug-Sept, p. 13-22

20. Roberts, S., Jannise, R., 1981, On target in the Tuscaloosa tDrilling , v. 42, 13,no. Oct, p. 125, 127-128, 130, 132

21. Salle, H. P., 1987, MWD (Measurement While Drilling) systemmonitor drilling efficiency: Offshore, v. 47, 4,no. Apr, p. 42-43

22. Schroeter, D. R., Chan, H. W., 1988, Successful application drilling technology extends EPMI's (Esso Production MalaysiaInc.) directional drilling capability: 7th SPE, et al., Offshore South East Asia Conference, v.,,no. 2 Feb - 5 Feb, p. 98-111

23. Schroeter, D. R., Wah, C. H., 1988, Successful application odrilling technology extends EPMI's (Esso Production MalaysiaInc.) directional capacity: SPE Petroleum Engineering International Meeting, v.,,no. 1 Nov - 4 Nov, p. 453-464

24. Stanley, D., Walker, C., 1987, MWD (Measurement While Drilling) takes on horizontal drilling: Oilman, v.,,no. Mar, p. 56-57

25. Tarr, B. A., Kuckes, A. F., AC, M., 1990, Use of a new rangintool to position a vertical well adjacent to a horizontal well: 65th Annual SPE Technology Conference, v.,,no. 23 Sept - 26 Sept, p421-430

26. Thorogood, J. L., 1988, Instrument performance models andtheir application to directional surveying operations: 63rd Annual SPE Technology Conference, v.,,no. 2 Oct - 5 Oct, p. 291-303



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27. Thorogood, J. L., Knott, D. R., 1989, Surveying techniques wa solid-state magnetic multishot device: SPE/IADC Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 841-856

28. Thorp, M., 1987, An analysis of discrepancies between gyro surveys: SPE/IADC Drilling Conference, v.,,no. 15 Mar - 18 Mar, p. 103-110

29. Webb, S., Ravotti, C., 1985, Directional drilling for undergrouncoal gasification: the state-of-the-art: 11th Annual DOE Morgantown Energy Technology Center Underground Coal Gasification Symposium, v.,,no. 11 Aug - 14 Aug, p. 37-54

30. Whitson, C. D., Sandison, G. F., 1985, Long reach drilling in tGulf of Mexico: IADC/SPE Drilling Conference, v.,,no. 5 Mar - 8 Mar, p. 433-437

31. Zusling, D. H., Wilson, R. A., 1989, Improved magnetic surveying techniques: field experience: SPE Offshore Europe Conference, v. 1,,no. 5 Sept - 8 Sept, p.

32. Schuh, F.J., 1992, Trajectory equations for constant tool faceangle deflections, Proceedings of the SPE Drilling Conference: New Orleans, LA, Feb 18-21, pp 111-123.

33. Cheatham, C.A., Shih, S, Curchwell, D.L., Woody, J.M., Rodney, P.F., 1992, Effects of magnetic interference on directioanl surveys in horizontal wells, Proceedings of the SPE Drilling Conference: New Orleans, LA, Feb 18-21, pp 101-110

Sensors And Interpretation

1. Allen, D., Best, D., Clark, B., Hache, J. M., Kienitz, C., RouleC., et al., 1989, Logging while drilling: Oilfield Review, v. 1,,no. Apr, p. 4-17

2. Allen, D. F., Sheppard, M. C., Rasmus, J. C., Ahmed, U., 199Real-time formation analysis can help drilling decisions: Proceedings - Drilling Conference, v.,,no. 11 Mar, p. p 153-165

3. Anon., 1967, New drilling-data system demonstrated: Oil & Gas Journal, v. 65, 51,no. 18 Dec, p. 45

4. Anon., 1978, How the Measurement While Drilling market is shaping up: Ocean Industry, v. 13, 6,no. June, p. 51-53

5. Anon., 1978, MWD: State-of-the-art. Conclusion. Acoustic, Esystems due in 1979: Oil & Gas Journal, v. 76, 36,no. Sept, p. 119-123



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6. Anon., 1979, Use of wireline serviceds during the drilling pha(utilization des diagraphies et autres services pendant le foraSchlumberger Algeria Well Evaluation Conference, v.,,no. Dec, p. III-1-III-20

7. Anon., 1982, IFP (Institut Francais du Petrole) Measuring WhDrilling System (MWD): Ind Petrol Gaz-Chim, v. 50, 542,no. April, p. 55,57

8. Anon, 1982, Measurement While Drilling, latest oilfield technology: Oil Gas Digest, v. 4, 11,no. 15 Nov, p. 22

9. Anon., 1984, MWD (Measurement While Drilling) economics still a problem: Offshore, v. 44, 11,no. Oct, p. 66-67

10. Anon, 1984, MWD (Measaurement While Drilling) innovationcould sharply reduce drilling costs: Ocean Industry, v. 19, 6,no. June, p. 38-40

11. Anon., 1985, A user's guide to MWD (Measurement While Drlling) logging in the Gulf of Mexico: Oil Patch, v. 10, 3,no. May, p. 18, 20, 22

12. Anon., 1986, Combining MWD (Measurement While Drilling)systems into a single package: Oilman, v.,,no. Nov, p. 40,43

13. Anon., 1987, MWD triple combo closes the gap: Oilman, v.,,no. May, p.

14. Anon., 1988, Vendors provide wide array of MWD tools: Petroleum Engineer International, v. 5, 60,no., p. 57-61

15. Anon., 1989, Manufacturers offer many choices in MWD (Measurement While Drilling) systems: Petroleum Engineer International, v. 61, 5,no. May, p. 29-30-32

16. Anon., 1990, Many MWD (Measurement While Drilling) choices available: Petroleum Engineer International, v. 5, 62,no. May, p. 37-38, 40

17. Arps, J. L., 1979, Downhole Measurements While Drilling - atechnology for the 80's: Petroleum Engineer International, v.,,no. Oct, p.

18. Bates, T. R., Jr., Tanguy, D. R., 19//?//, Downhole MeasuremeWhile Drilling: World Petroleum Congress, v.,,no., p.

19. Burgess,, T, Voison, B., 1992, Advances in MWD technologyimprove real-time data: Oil & Gas Journal, v. v 90, n 7,no. 17 Feb, p. p 51&

20. Cahill, J., 1966, Drill-pipe log is good problem solver: Oil & Gas Journal, v. 64, 39,no. 26 Sept, p. 106-108



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21. Cozens, A., 1977, Coming soon: a new era in drilling: Offshore, v. 37, 13,no. Dec, p. 78, 81-82

22. Cozens, A., 1978, Downhole technology is moving forward: Offshore, v. 38, 6,no. 5 June, p. 72, 75-76

23. Cozens, A., McDonald, W. J., 1977, MWD will broaden offshohorizons: Offshore, v. 37, 13,no. Dec, p. 78, 87-88

24. Evans, H. B., Dowsett, R., Weeks, K., Zoeller, W., Huchital, JS., Yan, Y. M., 1987, Recommendation for standardization oflog format, correction charts, and definitions of MeasurementWhile Drilling: SPE/IADC Drilling Conference, v.,,no. 15 Mar - 18 Mar, p. 773-792

25. Feneyrou, G., Quichaud, C., Rayunnal, J., Roux, C., 1979, Sand VA logs pass 2-year offshore, onshore field tests: Oil & Gas Journal, v. 77, 11,no. Mar, p. 55-69

26. Fontenot, J. E., 1986, Measurement While Drilling - a new toJournal of Petroleum Technology, v. 38, 2,no. Feb, p. 128-130

27. Gangopadhyay, S., 1987, Application of artificial intelligence MWD (Measurement While Drilling) interpretation: , v.,,no. Janp.

28. Gearhart, M., Mosely, L. M., Foster, M., 1986, Current state othe art of MWD (Measurement While Drilling) and its application in exploration and development drilling: SPE Petroleum Engineering International Meeting, v. 1,,no. 17 Mar - 20 Mar, p. 515-523

29. Gearhart, M., Mosley, L. M., Foster, M., 1986, Current state othe art of MWD (Measurement While Drilling) and its application in exploration and development drilling: Annual AAPG-SEPMPEMD-DPA Convention, v.,,no. 15 June - 18 Junep.

30. Grosso, D. S., Rader, D., Raynal, J. C., 1983, Report on MW(Measurement While Drilling) experimental downhole sensors(SPE-10058): Journal of Petroleum Technology, v. 35, 5,no. May, p. 899-904

31. Gstalder, S., Lutz, J., Quichaud, C., Raynal, J., Raynaud, M.1971, Dynamic theory of drilling and instantaneous logging: 46th Annual SPE of AIME Fall Meeting, v.,,no., p.

32. Helander, D. P., 1966, Here are ways you can log formationswhile drilling: Oil + Gas Equipment, v. 12, 11,no. Sept, p. 6-7

33. Henderson, B., Cluchey, M. O., 1987, New MWD (MeasuremWhile Drilling) applications using a slimline fully retrievable



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MWD tool: SPE/IADC Drilling Conference, v.,,no. 15 Mar - 18 Mar, p. 87-93

34. Honeybourne, W., 1985, Formation MWD (Measurement WhDrilling) benefits evaluation and efficiency: Oil & Gas Journal, v. 83, 8,no. 25 Feb, p. 83-92

35. Hutchinson, M. W., 1990, Measurement while and after drillinby multiple service companies through upper carboniferous formations at a borehole test facility, Kay County, Oklahoma:v.,,no., p.

36. Legros, F. W., Jr., Martin, C. A., 1985, Multisensor MWD (Measurement While Drilling) system successfully used: Drilling Contractor, v. 41, 6,no. June, p. 32-34

37. Mabile, C. M., Amaudric du Chaffaut, B., Hamelin, J. P. A., LFonta, J. G. M., 1989, An expert system helps in formation recognition: , v.,,no. 25 June - 28 June, p. 117-122

38. McDonald, W. J., 1978, MWD state of the art, part 2, four different systems used for MWD: Oil & Gas Journal, v. 76, 14,no., p. 115-124

39. Mills, R. C., 1987, Bright lights on petroleum technology: 62nd Annual SPE Technology Conference, v.,,no. 27 Sept - 30 Sept, p7-12

40. Mills, W. R., Stromswold, D. C., Allen, L. S., 1991, Advances nuclear oil-well logging: Nuclear Geophysics-International Journal of Radiation Applications and Intrumentation Part E, v. v 5, n 3,no., p. p 209-227

41. Moore, W. D., III, 1979, Drilling report. Drilling technology willplay bigger role in 1979: Oil & Gas Journal, v. 76, 38,no. Sept, p. 137-138

42. Ng, F., 1989, Recommendation for MWD tool reliability statistics: , v.,,no. 8 Oct - 11 Oct, p.

43. Orban, J. J., Dennison, M. S., Jorion, B. M., Mayes, J. C., 19New ultasonic caliper for MWD operations: Proceedings - Drilling Conference, v.,,no. 11 Mar, p. p 439-448

44. Pollard, M., 1987, Potentials in Measurement While Drilling: 3rd Norwegian Petroleum Society, Northern Europe Drilling Conference, v.,,no. 2 Nov - 4 Nov, p.

45. Reed, P., 1939, Amerada develops special rotary drill stem fosimultaneous elecrical logging and drilling: Oil & Gas Journal, v.,,no. 17 Nov, p. 68-76



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46. Roberts, A., Newton, R., Stone, F., 1982, MWD (MeasuremeWhile Drilling) field use and results in the Gulf of Mexico: 57th Annual SPE of AIME Fall Technology Conference, v.,,no. 26 Sept - 29 Sept, p.

47. Rochon, R. W., 1972, New developments in well informationv.,,no. Jan, p. 13-25

48. Sankur, V., Weber, L. S., Masoner, L. O., 1990, Developmensockeye field in offshore California: a case history: 60th Annual SPE California Region Meeting, v.,,no. 4 Apr - 6 Apr, p. 305-315

49. Spinnler, R. F., Stone, F. A., 1978, MWD: state of the art, parMWD program nearing commerciality: Oil & Gas Journal, v. 76, 18,no. 1 May, p. 59-66

50. Tanner, K. D., Young, F. S., Jr., 1972, Recent developmentson-site well monitoring systems: 19th Annual SW Petroleum Short Course Assn. Meeting, v.,,no., p. 31-42

51. Teige, T. G., Undersrud, E., Rees, M., 1986, (R) MWD (Measurement While Drilling): a case study in applying new technology in Norwegian Block 34/10: Drilling Engineer, v. 1, 6,no. Dec, p. 426-434

52. Worthington, P. F., 1988, Scientific benefits of downhole measurements in the ocean drilling program: American Geophysicists Union Fall Meeting, v. 69, 44,no. 6 Dec - 11 Dec,p. 1047

53. Zoeller, W. A., 1978, Instantaneous log is based on surface drilling data: World Oil, v. 187, 1,no. July, p. 97-98, 100, 102, 105

Formation Evaluation Tools - General

1. Breitmeier, J. M., Tosch, W. C., Adewumi, M. A., Miller, M. N.1989, Investigation of radial invasion of mud filtrate in porousmedia: 30th Annual SPWLA Logging Symposium, v.,,no. 11 June - 14, p.

2. Chan, A. K., Puri, A., Rodney, P. F., 1988, MWD (MeasuremeWhile Drilling) radio frequency logging with borehole intersected by bed boundaries: 58th Annual Society of Exploration Geophysicists International Meeting, v. 1,,no. 30 Oct - 3 Nov, p. 135-138

3. Fertl, W. H., 1973, What to remember when interpreting mud gcutting: World Oil, v. 177, 4,no. Sept, p. 67-68, 70-72



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4. Hutchinson, M. W., 1991, Comparisons of MWD, wireline,andcore data from a borehole test facility: Formation Evaluation and Reservoir Geology Proceedings - SPE Annual Technical Conference and Exhibition, v. v omega,,no. 6 Oct, p. p 741-754

5. Kirton, P. J., 1986, Multi sensor MWD (Measurement While Drilling) services: current applications and future developmenIBC Technology Services Ltd. Measurement While Drilling Conference, v.,,no. 6 June, p.

6. Kishel, J. F., Kisling, J., Tanguy, D. R., Young, D., 1973, Development and applications of a downhole tool to detect gawhile drilling: 48th Annual SPE of AIME Fall Meeting, v.,,no., p. 12 pp

7. Koopersmith, C. A., Barnett, W. C., 1987, Environmental parameters affecting neutron porosity, gamma ray, and resistimeasurements made while drilling: 62nd Annual Technical Conference, v.,,no. 27 Sept - 30 Sept, p.

8. Rasmus, J. C., Bergt, D., 1989, Formation characterization utilizing MWD measurements and drilling derived formation impedance: SPWLA, 30th Annual Logging Symposium, v.,,no. 11 June - 14 June, p.

9. Tanguy, D. R., Zoeller, W. A., 19//?//, Applications of Measurements While Drilling: Annual Fall Technology Conference, v.,,no. 5 Oct - 7 Oct, p.

Mwd Interpretation - General

1. Alixant, J.-J., et al., 1989, Real time permeability estimate whdrilling tight gas formations: Submitted to SPE Annual Conference, v.,,no. 8 Oct - 11 Oct, p.

2. Anon., 1989, Staged field experiment No. 2: application of advanced geological, petrophysical and engineering technoloto evaluate and improve gas recovery from low permeability sandstone reservoirs: Travis Peak Formation, North ApplebyField, Nacogdoches County, Texas: Gas Research Institute Report No. GRI-89/0140, v. 1,,no. June, p.

3. Anon., 1989, Effect on filtration: International Well Control Symposium/Workshop, v.,,no. 28 Nov - 29 Nov, p. 137-147

4. Baker, C., Fristad, P., Seim, P., 1987, Reservoir evaluation wMWD (Measurement While Drilling) logs: present potential anfuture requirements: 28th SPWLA Annual Logging Symposium, v.,,no. 29 June - 2 July, p.



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5. Boone, D. E., 1984, Production `84. Finding productive zoneoverlooked by wireline logs: World Oil, v. 199, 6,no. Nov, p. 61-65

6. Boone, D. E., 1987, New logging concept defines clay invasiowhile drilling: 62nd SPE Annual Technology Conference, v.,,no. 27 Sept - 30 Sept, p. 471-476

7. Chin, M., Suresh, A., Holbrook, P., Afleck, L., Robertson, H.,1986, Formation evaluation using repeated MWD logging measurements: 27th SPWLA Annual Logging Symposium, v.,,no. 9 June - 13 June, p.

8. Chin, W., Suresh, A., Holbrook, P., Affleck, L., Robertson, H.1986, Formation evaluation using repeated MWD (MeasuremWhile Drilling) logging measurements: 27th SPWLA Annual Logging Symposium, v.,,no. 9 June - 13 June, p.

9. Coope, D. F., 1986, (9) Formation evaluation using measurements recorded while drilling: IBC Technology ServicesLtd. Measurement While Drilling Conference, v.,,no. 6 June, p. PROC 29 pp, 12 refs

10. Coope, D. F., Hendricks, W. E., 1984, Formation evaluation using measurements recorded while drilling: 25th SPWLA Annual Logging Symposium, v.,,no. 10 June - 13 June, p.

11. Desbrandes, R., 1989, Invasion diameter and superchargingtime-lapse MWD/LWD logging: International Well Control Symposium/Workshop, v.,,no. 28 Nov - 29 Nov, p. 115-137

12. Fertl, W. H., Pilkington, P. E., 1975, How to find transition zonin soft formations: World Oil, v. 180, 5,no. Apr, p. 98-100, 102

13. Greif, M. A., Koopersmith, C. A., 1985, Petrophysical evaluatiof thinly bedded reservoirs in high angle/displacement development wells with the no recorded lithology logging system: 10th Canadian Well Logging Society Formation Evaluation Symposium, v.,,no. 29 Sept - 2 Oct, p.

14. Hendricks, W. E., Coope, D. F., Yearsley, E. N., 1984, MWDFormation evaluation case histories in the Gulf of Mexico: 59th Annual Technology Conference, v.,,no. 16 Sept - 19 Sept, p.

15. Itannenbaum, E., Sutcliffe, B., Franks, A., 1988, A compositelithology log while drilling: Annual AAPG-SEPM-EMD-DPA Convention, AAPG Bulletin, v. 72, 2,no. Feb, p. 253

16. Kirkman, M., 1986, Multi-sensor MWD (Measurement While Drilling) moves towards a more quantitative approach: Noroil, v. 14, 3,no. Mar, p. 36-37



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17. Mabile, C. M., Amaudric du Chaffaut, B., Hamelin, J. P. A., LFonta, J. G. M., 1989, An expert system helps in formation recognition: , v.,,no. 25 June - 28 June, p. 117-122

18. Mabile, C. M., Amaudric du Chaffaut, B., Hamelin, J. P. A., LFonta, J. G. M., 1989, An expert system helps in formation recognition: SPE Petroleum Computer Conference, v.,,no. June-July, p. 117-122

19. McAdams, J. B., Mercer, R. F., 1977, Detailed hydrocarbon loenhance formation evaluation: 18th SPWLA Annual Symposium, v.,,no., p.

20. Norve, K. H., Saether, H., 1989, Field experience using the fsuite MWD-combination for reservoir logging and evaluation:30th SPWLA Annual Logging Symposium, v.,,no. 11 June - 14 June, p.

21. Nuckols, E. B., Cobern, M. E., Couillard, B., 1985, Formationevaluation by MWD (Measurement While Drilling): Petroleum Management, v. 7, 12,no. Dec, p. 46-49

22. Overton, H. L., Zied, M. D., 1971, A progress report on shaleelectric log: 12th SPWLA Annual Logging Symposium, v.,,no., p.

23. Rao, M. V., Fontenot, J. E., 1988, MWD gains as formation-evaluation tool: Oil & Gas Journal, v. 86, 6,no., p. 44-48

24. Rao, M. V., Fontenot, J. E., 1988, MWD (Measurement WhileDrilling) poised for future: MWD gains as formation-evaluationtool: Oil & Gas Journal, v. 86, 6,no. 8 Feb, p. 44-48, 25 refs

25. Speers, J. M., Watkins, L. A., Barry, A., Miller, J. F., RobinsoL. J., Jr., 1980, Exxon MWD tools yield unexpected downholedata: Oil & Gas Journal, v. 78, 16,no. 21 Apr, p. 88-90

26. Squire, W. D., 1990, Acoustic systems find uses in oil and gaindustry: American Oil & Gas Reporter, v. 33, 8,no. Aug, p. 35, 37

27. Stanley, D. J., Ardrey, W. E., 1987, Improve MWD (Measurement While Drilling) data interpretation: Drilling , v. 48, 1,no. Jan, p. 22-24

28. Stayton, R. J., Peach, S. R., 1990, Long radius well taps vertfractures: Drilling Contractor, v. 46, 4,no. June, p. 57-59

29. Turville, J. A., Troy, G. W., 1983, Formation evaluation: benefits of downhole logging while drilling (DLWD): Annual AAPG-SEPM-EMD-DPA Convention, AAPG Bulletin, v. 67, 3,no. 17 April - 20 April, p. 560



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30. Whittaker, A., Dowsett, R., Nigh, E., Brooks, A., MacphersonJ., 1986, Integrated formation evaluation data base combininMWD (Measurement While Drilling) and real-time surface measurements with conventional logging data: Annual AAPG-SEPM-EMD-PDA Convention; AAPG Bulletin, v. 70, 5,no. 15 June - 18 June, p. 663

31. Whittaker, A. H., Macpherson, J. D., Dowsett, R. E., Turvill, JA., 1986, An integrated approach to formation evaluation usinMeasurement While Drilling (MWD) logs in combination with enhanced mud logging and other surface measurement techniques: 10th SPWLA Aberdeen Chapter Europe FormationEvaluation Symposium, v.,,no. 22 April - 25 April, p.

32. Murphy, W.F., Auzerais, F.M., Luling, M.G., Anderson, B.I., Tomanic, J., Bonner, S.D., Sakurai, S., and Wolcott, D.S., 19Interpretation of a heavy mineralogy formation, North Slope oAlaska, using Logging-While-Drilling 2 MHz resistivity: Laboratory measurement, modeling, and wireline comparisonFormation Evaluation and Reservoir Geology Proceedings ofthe SPE Annnual Technical Conference and Exhibition: Washington, DC, Oct 4-7, SPE 24677, pp 155-170

33. Cantrell, L.A., Paxson, K.B., and Keyser, B.L., 1992, Case histories of MWD as wireline replacement: An evolution of formation evaluation philosophy, Formation Evaluation and Reservoir Geology Proceedings of the SPE Annnual TechnicConference and Exhibition: Washington, DC, Oct 4-7, SPE 24673, pp 115-130.

34. Anon, 1992, Formation evaluation and reservoir geology, Formation Evaluation and Reservoir Geology Proceedings ofthe SPE Annnual Technical Conference and Exhibition: Washington, DC, Oct 4-7, p 1037.

35. Domangue, P.M. and Peressini, R.J., 1992, Novel applicationopen systems at the wellsite, Proceedings of the SPE PetroleumComputer Conference: Houston, TX Jul 19-22, SPE 24424, pp 55-67.



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Gamma Ray Tools and Interpretation

1. Bryant, T. M., Gage, T. D., 1988, API PIT calibration of MWD(Measurement While Drilling) gamma ray tools: 29th Annual SPWLA Logging Symposium, v.,,no. 5 June - 8 June, p.

2. Coope, D. F., 1983, Gamma ray Measurement While DrillingLog Analyst, v. 24, 1,no. Jan-Feb, p. 3-9

3. Jan, Y-M., Campbell, J. R., 1984, Borehole correction of MWgamma ray and resistivity logs: 25th SPWLA Annual Logging Symposium, v.,,no. June, p.

4. Jan, Y.-M., Harrell, J. W., 1987, MWD directional-focused gamma ray-a new tool for formation evaluation and drilling control in horizontal wells: 28th SPWLA Annual Logging Symposium, v.,,no. 29 June - July 2, p.

5. Jan, Y.-M., Harrell, J. W., 1987, MWD directional-focused gamma ray-a new tool for formation evaluation and drilling control in horizontal wells: 28th SPWLA Annual Logging Symposium, v.,,no. 29 June - July 2, p.

6. Jensen, J. L., Triptree, D. S., 1989, A comparison of wireline aMWD gamma ray spectral responses: SAID, 12th Logging Intl. Symposium, v.,,no. Oct, p. 24, 25, 27

7. Meisner, J., Brooks, A., Wisniewski, W., 1985, A new Measurement-While-Drilling gamma ray log calibrator: 26th Annual SPWLA Logging Symposium, v.,,no. 17 June - 20 June, p

8. Nuckols, E. B., Cobern, M. E., Couillard, B., 1985, Formationevaluation utilizing MWD (Measurement While Drilling) gamma ray and resistivity measurements with special emphaon formation invasion: 10th Canadian Well Logging Society Formation Evaluation Symposium, v.,,no. 29 Sept - 2 Oct, p.

9. Seaton, P., Roberts, A., Schoonover, L., 1983, New MWD (Measurement While Drilling) -gamma system finds many fielapplications: Oil & Gas Journal, v. 81, 8,no. 21 Feb, p. 80-84

10. Wilson, R. D., Koizumi, C. J., Dean, S. H., 1985, Spectral gamma-ray calculations with an efficient and accurate radiatitransport model: 26th Annual SPWLA Logging Symposium, v.,,no. 17 June - 20 June, p.



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Resistivity Tools And Interpretation

1. Allen, D. F., Luling, M. G., 1989, Integration of wireline resistivity data with dual depth of investigation 2-mhz MWD resistivity data: SPWLA Annual Symposium, v.,,no. 22 June - 14 June, p.

2. Anderson, B., Bonner, S., Luling, M. G., Rosthal, R., 1990, Response of 2mhz LWD (Logging While Drilling) resistivity and wireline induction tools in dipping beds and laminated formations: 31st Annual SPWLA Logging Symposium, v.,,no. 24 June - 27 June, p.

3. Baker, C., Fristad, P., Seim, P., 1987, Reservoir evaluation wMWD (Measurement While Drilling) logs: present potential anfuture requirements: 28th SPWLA Annual Logging Symposium, v.,,no. 29 June - 2 July, p.

4. Barnett, W. C., Meyer, W. H., 1991, Radial response of a 2-MMWD propogation resistivity sensor: Formation Evaluation and Reservoir Geology Proceedings - SPE Annual Technical Conference and Exhibition, v. v omega,,no. 6 Oct, p. p 481-490

5. Brooks, A. G., Hall, H. E., 1989, Calculation of electromagnetool response by a finite element method: Society of Petroleum Engineers, v.,,no. 8 Oct - 11 Oct, p.

6. Cahill, J., 1966, Use of the drill pipe electric log: 7th Annual SPWLA Symposium, v.,,no. 8 May - 11 May, p.

7. Clark, B., Allen, D. F., Best, D., Bonner, S. D., Jundt, J., LulinM. G., et al., 1990, Electromagnetic propagation logging whiledrilling : theory and experiment: 63rd Annual SPE Technology Conference, v.,,no. 2 Oct - 5 Oct, p. 103-117

8. Clark, B., Luling, M. G., Jundt, J., Ross, M., Best, D., 1988, Adual depth resistivity measurement for FEWD (Formation Evaluation While Drilling): 29th Annual SPWLA Logging Symposium, v.,,no. 5 June - 8 June, p.

9. Cobern, M. E., 1986, (R) Application of MWD (Measurement While Drilling) resistivity relogs to evaluation of formation invasion: IBC Technology Services Ltd. Measurement While Drilling Conference, v.,,no. 6 June, p.

10. Cobern, M. E., Nuckols, E. B., 1985, Application of MWD (Measurement While Drilling) resistivity relogs to evaluation oformation invasion: 26th Annual SPWLA Logging Symposium, v.,,no. 17 June - 20 June, p.



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11. Coope, D., Shen, L. C., Huang, F. S. C., 1984, The theory ofmhz resistivity tool and its application to Measurement While Drilling: Log Analyst, v. 25, 3,no. May-June, p. 35-46

12. Coope, D. F., Yearsley, E. N., 1986, Evaluation of thin beds alow-resistivity pays using EWR: 10th SPWLA Aberdeen ChapteEurope Formation Evaluation Symposium, v.,,no. 22 Apr - 25 Apr, p.

13. Coope, D. F., Yearsley, E. N., 1986, Formation evaluation usEWR (Electromagnetic Wave Resistivity) logs: SPE Petroleum Engineering International Meeting, v.,,no. 17 Mar - 20 Mar, p. 415-425Desbrandes, R., 1989, Interpretation of MWD dual resistivity measurements: permeability estimate: International Well Control Symposium/Workshop, v.,,no. 28 Nov - 29 Nov, p. 147-159

14. Evans, H. B., Brooks, A. G., Meisner, J. E., Squire, R. E., 19A focused current resistivity logging system for MWD (Measurement While Drilling): 62nd Annual SPE Technology Conference, v.,,no. 27 Sept - 30 Sept, p. 145-154

15. Fredericks, P. D., Hearn, F. P., Wisler, M. M., 1989, Formatioevaluation while drilling with a dual propagation resistivity tooSPE Annual Conference, v.,,no. 8 Oct - 11 Oct, p.

16. Fredericks, P. D., Hearn, F. P., Wisler, M. M., 1989, Formatioevaluation using an MWD dual-propagation resistivity tool: SAID, 12th Logging International Symposium, v.,,no. 24 Oct - 27 Oct, p.

17. Gianzero, S., et al., 1985, A new resistivity tool for MeasuremWhile Drilling: 26th Annual SPWLA Logging Symposium, v.,,no. 17 June - 20 June, p.

18. Gianzero, S., Chemali, R., Su, S. M., 1986, Determining the invasion near the bit with the MWD (Measurement While Drilling) toroid sonde: 27th Annual SPWLA Logging Symposium, v.,,no. 9 June - 13 June, p.

19. Grupping, T. I. F., Harrell, J. W., Dickinson, R. T., 1988, Receperformance of the dual resistivity MWD (Measurement WhileDrilling) tool: SPE, et al., Europe Petroleum Conference, v.,,no. 17 Oct - 19 Oct, p. 411-422

20. Grupping, T. I. F., Harrell, J. W., Dickinson, R. T., 1988, Performance update of a dual-resistivity MWD (MeasuremenWhile Drilling) tool with some promising results in oil-based mud applications: 63rd Annual SPE Technology Conference, v.,,no. 2 Oct - 5 Oct, p. 73-85



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21. Harrison, W. H., Rubin, L. A., Mazza, R. L., Yost, A. B., II, 1990, Air-drilling electromagnetic, MWD (Measurement WhileDrilling) system development: IADC/SPE Drilling Conference, v.,,no. 27 Feb - 2 Mar, p. 485-495

22. Holbrook, P., 1985, The effect of mud filtrate invasion on theEWR log - a case history: 26th SPWLA Annual Logging Symposium, v.,,no. 17 June - 20 June, p.

23. Logan, R., 1990, Application of an MWD (Measurement WhilDrilling) propagation restivity and neutron tool: Annual AAPG-SEPM-EMD-DPA Convention, v.,,no. 3 June - 6 June, p.

24. Mack, S. G., Rodney, P. F., Bittar, M. S., 1992, MWD tool accurately measures 4 resisitivities: Oil & Gas Journal, v. v 90, n 21,no. 25 May, p. p 42-46

25. MacMillan, M. W., 1988, Real-time electromagnetic propagatiresistivity and memory for MWD: 11th European Formation Evaluation Symposium, v.,,no. 14 Sept - 16 Sept, p.

26. Mills, B., 1940, Simultaneous and continuous electrical logginand drilling achieved: Oil Weekly (Now World Oil), v. 96, 4,no. 1 Jan, p. 16-20

27. Overton, H. L., 1970, Resistivity logging from shale slurries: 11th Annual SPWLA Logging Symposium, v.,,no., p.

28. Rodney, P. F., Bartel, R., 1988, Design of a propagating wavresistivity sensor in order to minimize the influence of borehofluids on the sensor response: 63rd Annual Technical Conferenceand Exhibition of SPE, v.,,no. 2 Oct - 5 Oct, p.

29. Rodney, P. F., Thompson, L. W., Wisler, M. M., Meador, R. A1983, The electromagnetic wave resistivity MWD (MeasuremeWhile Drilling) tool: 58th Annual SPE of AIME Technology Conference, v.,,no. 5 Oct - 8 Oct, p.

30. Rubin, L. A., 1989, Status report on EM (Electromagnetic)-baMeasurement While Drilling: New Mexico Institute Mining Technology Petroleum Technology into the Second Century Symposium, v.,,no. 16 Oct - 19, p. 291-301

31. Smith, H. E., 1983, Toroidal coupled Measurements While Drilling: IADC/SPE Drilling Conference, v.,,no. 20 Feb - 23 Feb,p. 55-58

32. Sorensen, K., 1989, A method for measuremeant of the electformation resistivity while auger drilling: First Break, v. 7, 10,no. Oct, p. 403-407



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33. Turvill, J. A., Hebel, J. B., Evans, H. B., 1989, Optimizing design and performance of an MWD (Measurement While Drilling) resistivity sensor: 64th Annual SPE Technology Conference, v.,,no. 8 Oct - 11 Oct, p. 502-520

34. Wu, J. Q., Wisler, M. M., 1990, Effects of eccentering MWD (Measurement While Drilling) tools on electromagnetic resistivity measurements: 31st Annual SPWLA Logging Symposium, v.,,no. 24 June - 27 June, p.

35. Zhou, Q., Hilliker, D. J., 1991, MWD resistivity tool response a layered medium: Geophysics, v. v 56, n 11,no. Nov, p. p 1738-1748

Neutron Tools And Interpretation

1. Anon, 1986, NL (National Lead) uncovers neutron MWD (Measurement While Drilling) tool: Oilman, v.,,no. Nov, p. 36, 38

2. Burnett, T. M., Koopersmith, C. A., Spross, R. L., 1990, Drill collar effects on MWD (Measurement While Drilling) epithermal and capture gamma ray neutron porosity measurements: 31st Annual SPWLA Logging Symposium, v.,,no. 24 June - 27 June, p.

3. Evans, M., Wraight, P., Marienbach, E., Rhein-Knudsen, E., Best, D., 1988, Formation porosity Measurement While Drillin29th Annual SPWLA Logging Symposium, v.,,no. 5 June - 8 June,p.

4. Gartner, M., 198//?//, Neutron porosity Measurement While Drilling: SPWLA Europe ???, v.,,no., p.

5. Kennedy, J. L., 1970, Drilling porosity log proves accurate: Oil & Gas Journal, v. 68, 34,no. 24 Aug, p. 53-55

6. Roesler, R. F., Barnett, W. C., Paske, W. C., 1987, Theory aapplication of a measurement while drilling neutron porosity sensor: SPE/IADC Drilling Conference, v.,,no. 15 Mar - 18 Mar, p. 81-86

7. RoeslerR. F., Barnett, W. C., Paske, W. C., Koopersmith, C. 1987, Theory and applications of an MWD (Measurement WhDrilling) neutron porosity sensor: 11th Canadian Well Logging Society Formation Evaluation Symposium, v.,,no. 8 Sept - 11 Sept, p.



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8. Simms, G. J., Koopersmith, C. A., 1989, Hydrocarbon type identification using MWD neutron porosity logging: a case study: SPE Annual Conference, v.,,no. 8 Oct - 11 Oct,

9. Simms, G. J., Koopersmith, C. A., 1991, Hydrocarbon type identification with MWD neutron porosity logging. A case studySPE Formation Evaluation, v. v 6, n 3,no. Sep, p. p 343-348

10. Wraight, P., Evans, M., Marienbach, E., Rhein-Knudsen, E., Best, D., 1989, Combination formation density and neutron porosity Measurements While Drilling: SPWLA Annual Symposium, v.,,no. 11 June - 14 June, p.

11. Nordstom, R., A new MWD neutron porosity device providesharsh environment performance, IEE Nuclear Science Symposium, Arlington, VA, Paper 4B2, October 1990.

12. Hubner, B.G., W.D. Bruck, and Dudeck, J.H., A novel neutrodetector for porosity logging, IEEE Nuclear Science Symposium, Arlington, VA, Paper 4B5, October 1990.

Density Tools And Interpretation

1. Allen, D. F., Best, D. L., Evans, M., Holenka, J., 1990, The effeof wellbore condition on wireline and MWD (Measurement While Drilling) neutron density logs: 65th Annual SPE Technology Conference, v.,,no. 23 Sept - 26 Sept, p. 345-356

2. Best, D., Wraight, P., Holenka, J., 1990, An innovative approato correct density Measurement While Drilling for hole size effect: 31st Annual SPWLA Logging Symposium, v.,,no. 24 June - 27 June, p.

3. Paske, W. C., Mack, S. G., Rao, M. V., Spross, R. L., Twist, JR., 1990, Measurement of hole size while drilling: 21st Annual SPWLA Logging Symposium, v.,,no. 24 June - 27 June, p.

4. Paske, W. C., Rao, M. V., Twist, J. R., Mack, S. G., Spross, RL., 1990, Theory and implementation of a borehole caliper measurement made while drilling: 65th Annual SPE TechnologyConference, v.,,no. 23 Sept, p. 335, 344

5. Paske, W. E., et al., 1987, Formation density logging while drilling: SPE Annual Fall Meeting, v.,,no. 27 Sept - 30 Sept, p.



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Radiation And Safety

1. Kurkoski, P. L., Holenka, J. M., Evans, M. L., 1991, Radiationsafety and environment for measurement-while-drilling. A different approach: Proceedings of the First International Conference on Health, Safety, and Evnvironment In Oil and GExploration and Production Part 1 (of 2), v.,,no. 11 Nov, p. p 553-561

Horizontal Holes

1. Ackert, D., Boetel, M., Marszalek, T., Clavier, C., Goode, P., Thambynayagam, M., et al., 1988, Looking sideways for oil: Tech Review (Schlumberger), v. 36, 1,no. Jan, p. 22-25, 28-31

2. Adamache, I., McIntyre, F. J., Pow, M., Lewis, D., Davis, R., Kuhme, A., et al., 1990, Horizonal well applications in a miscible flood: CIM Petroleum Society SPE International Technology Meeting, v.,,no. 10 June - 13 June, p.

3. Anderson, S. A., Conlin, J. M., Fjeldgaard, K., Hansen, S. A.,1990, Exploiting reservoirs with horizontal wells: the Maersk experience: Oilfield Review, v. 2, 3,no. July, p. 11-21

4. Anon., 1982, French drill horizontal drainhole using MWD: Drilling Contractor, v. 38, 2,no. Feb, p. 116-188

5. Anon., 1983, Horizontal well boosts Elf's Adriatic output: Offshore Engineer, v.,,no. April, p. 73-74

6. Anon., 1987, Horizontal drilling has bright future, says Elf: Drilling Contractor, v. 43, 4,no. June-July, p. 29-30

7. Anon, 1990, Using MWD (Measurement While Drilling) in shoradius horizontal wells: Ocean Industry, v. 25, 8,no. Oct, p. 36-37

8. Anon., 1991, Danish drill unusual offshore horizontal well: Drilling Contractor, v. 47, 1,no., p. 20-22

9. Anon., 1991, Horizontal drilling hold much promise: Drilling Contractor, v. 47, 1,no., p. 16, 18

10. Bellinger, C. E., 1991, Horizontal well in the Devonian Shale,Martin County, Kentucky: Proceedings of the 1991 SPE EasterRegional Conference and Exhibition, v.,,no. 23 Oct, p. p 315-322

11. Betts, P., Blout, C., Broman, B., Clark, B., Hibbard, L., Louis,A., et al., 1990, Acquiring and interpreting logs in horizontal holes: Oilfield Review, v. 2, 3,no. July, p. 34-51



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12. Bitto, R., Henderson, A. B., Broussard, L., 1990, Recent casehisotries of new well applications for horizontal drilling: SPE East Region Conference, v.,,no. 31 Oct - 2 Nov, p. 25-36

13. Brannin, C. S., Velser, L., Williams, M. P., 1990, Drilling a record horizontal well: a case history: IADC/SPE Drilling Confrence, v.,,no. 27 Feb - 2 Mar, p. 627-636

14. Briggs, G. M., 1989, How to design a medium-radium horizonwell: Petroleum Engineer International, v. 61, 9,no. Sept, p. 26, 30-32, 36-37

15. Briggs, G. M., 1990, Application of performance drilling to directional, horizontal wells: Offshore, v. 50, 2,no. Feb, p. 27-30

16. Broman, W. H., Stagg, T. O., Rosenzweig, J. J., 1990, Horizowell performance evaluation at Prudhoe Bay: CIM Petroleum Society SPE International Technology Meeting, v.,,no. 10 June - 13 June, p.

17. Burgess, T., Vande Siljke, P., 1990, Horizontal drilling comesage: Oilfield Review, v. 2, 3,no. July, p. 22-33

18. Carstens, E., 1988, Horizontal well drilling and completion: Norwegian Petroleum Direct Recovery from Thin Oil Zones Seminar, v.,,no. 21 April - 22 April, p.

19. Clark, A. C., Cocking, D. A., 1989, The planning and drilling othe world's first horizontal well from a semisubmersible rig: SPE/IADC Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 773-790

20. Claytor, S. B., Manning, K. J., Schmalzried, D. L., 1991, Drillina medium-radius horizontal well with aerated drilling fluid. A case study: Proceedings - Drilling Conference, v.,,no. 11 Mar, p. p 759-773

21. Claytor, S. B., Jr., Speed, J., King, R., 1989, Steerable systedrilling: the right angle for horizontal drilling: SPE Asia-Pacific Conference, v.,,no. 13 Sept - 15 Sept, p. 7-16

22. Conti, P. F., 1989, Controlled horizontal drilling: SPE/IADC Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 749-754

23. Crouse, P. C., 1989, Reserve potential due to horizontal drilliis substantial: World Oil, v. 209, 4,no. Oct, p. 47-49

24. Cunningham, A. B., Jay, K. L., Opstad, E., 1990, ApplicationsMWD (Measurement While Drilling) technology in nonconventional wells, Prudhoe Bay, North Slope Alaska: 31st Annual SPWLA Logging Symposium, v.,,no. 24 June - 27 June, p



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25. Cunningham, A. B., Jay, K. L., Opstad, E., 1992, Unconventional Prudhoe Bay wells benefit from MWD use: World Oil, v. v 213, n 5,no. May, p. p 43-53

26. Dech, J. A., 1988, Advances in horizontal drilling-directional control: Norwegian Petroleum Direct Recovery from Thin Oil Zones Seminar, v.,,no. 21 April - 22 April, p.

27. Dickinson, W., Pesavento, M. J., Dickinson, R. W., 1990, Daacquisition, analysis, and control while drilling with horizontalwater jet drilling systems: CIM Petroleum Society SPE International Technology Meeting, v.,,no. 10 June - 13 June, p.

28. Ehlers, R., Kracht, L., Witte, J., 1989, Case history of horizonwells drilled with navigation technology in European operationSPE/IADC Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 315-324

29. Fagin, R. A., Trusty, J. E., Emmet, L. R., Mayo, M. K., 1991, MWD resistivity tool guides bit horizontally in thin bed: Oil & Gas Journal, v. v 89, n 49,no., p. p 62-65

30. Fertl, W. H., Nice, S. B., 1988, Well logging in extended-reacand horizontal boreholes: 20th Annual SPE, et al., Offshore Technology Conference (OTC `88), v.,,no. 2 May - 5 May, p. 193-206

31. Fox, C., 1986, Rospo Mare - Elf keeps faith with horizontal wells: Offshore Engineer, v.,,no. Sept, p. 57-58

32. Giannesini, J. F., 1989, Horizontal drilling is becoming commonplace: here's how it's done: World Oil, v. 208, 3,no. March, p. 35-38, 40

33. Gianzero, S., Chemali, R., Su, S. M., 1990, Induction, resistivand MWD tools in horizontal wells: Log Analyst, v. 31, 3,no. May-June, p. 158-171

34. Gianzero, S. C., Chemali, R. E., Su, S. M., 1992, Induction, resistivity, and MWD tools in horizontal wells: Proceedings of the International Meeting on Petroleum Engineering, v.,,no. 24 Mar, p. 191-199

35. Gust, D., 1989, Horizontal drilling evolving from art to scienceOil & Gas Journal, v. 87, 30,no. 24 July, p. 43-46, 49-52

36. Gust, D., 1989, Horizontal drilling past, present, and future: CADE/CAODC Spring Drilling Conference, v.,,no. 26 April - 28 April, p.

37. Hammons, L. R., Barnett, W. C., Fisher, E. K., Sellers, D. H.,1991, Stratigraphic control and formation evaluation of



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horizontal wells using MWD: Drilling proceedings - SPE Annual Technical Conference and Exhibition, v. v delta,,no. 6 Oct, p. p 25-38

38. Hardman, P., 1986, Beckingham 36 horizontal well: SPE Europe Petroleum Conference (EUROPEC 90), v.,,no. 20 Oct - 22 Oct, p. 429-438

39. Hassen, B. R., MacDonald, A. J., 1990, Field comparison of medium-and long-radius horizontal wells drilled in the same reservoir: IADC/SPE Drilling Conference, v.,,no. 27 Feb - 2 Mar, p. 637-652

40. Jan, Y.-M., Harrell, J. W., 1990, MWD (Measurement While Drilling) directional - focused gamma ray - a new tool for formation evaluation and drilling control in horizontal wells: Directional Drilling, v.,,no., p. 189-197

41. Jelsma, H., Walker, C., 1989, Application of conventional drilling and MWD (Measurement While Drlling) equipment to medium radius horizontal wells: 3rd Annual IBC Technology Services Ltd. Offshore Drilling Technology Conference, v.,,no. 29 Nov - 30 Nov, p.

42. Jenkins, P. P., Ball, T. G., 1991, Horizontal drilling techniquesBritish coal-mines: Transactions of the Institution of Mining andMetallurgy Section A-Mining Industry, v. v 100,,no. Jan, p. p a11-a21

43. Jourdan, A. P., Mariotti, C., 1989, How to build and hold a 90angle hole: SPE/IADC Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 737-748

44. Karlsson, H., Cobbley, R., Jacques, G. E., 1989, New developments in short- medium, and long-radius lateral drillinSPE/IADC Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 725-736

45. Lang, W. J., Jett, M. B., 1990, Horizontal Wells: part 1: high expectations for horizontal drilling becoming reality: Oil & Gas Journal, v. 88, 39,no. 24 Sept, p. 70, 72, 74, 76, 79

46. Leake, J., Shray, F., 1991, Logging while drilling keeps horizontal wellon small target: Oil & Gas Journal, v. v 89, n 38,no. 23 Sep, p. p 53-59

47. Legris, B., Nazzal, G., 1989, Specifics of horizontal drilling inthe Zuidwal gas field: SPE Offshore Europe Conference, v.,,no. 5 Sept - 8 Sept, p.



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48. McCabe, C., 1990, Horizontal well opens up troll oil development: Ocean Industry, v. BE25, 8,no. Oct, p. 19-24

49. Montgomery, S. L., 1990, Techniques of horizontal drilling: concepts and consequences: Petroleum Frontiers, v. 7, 1,no., p.

50. Moore, S. D., 1987, High-angle drilling comes of age: Petroleum Engineer International, v. 59, 2,no. Feb, p. 18-20, 22

51. Moore, S. D., 1990, Oryx develops horizontal play: Petroleum Engineer International, v. 62, 4,no. April, p. 16, 20, 22

52. Moritis, G., 1989, More information from horizontal well survey: Oil & Gas Journal, v. 87, 11,no. 13 Mar, p. 63-65

53. Najia, W. K., Habib, K. H., Asada, J., 1991, Formation evaluation of a horizontal hole: Proceedings of the 7th Middle East Oil Show, v.,,no. 16 Nov, p. p 49-58

54. Nazzal, G., 1990, Horizontal wells: part 2: planning matches drilling equipment to objectives: Oil & Gas Journal, v. 88, 41,no. 8 Oct, p. 110, 112, 114-118

55. Nice, S. B., Fertl, W. H., 1990, New logging, completion techniques boost horizontal well productivity: Petroleum Engineer International, v. 62, 11,no. Nov, p. 20, 22-24, 26-29

56. Power, M. M., Chapman, R., O'Neal, R., 1990, Horizontal wesets depth record: horizontal well below 14,600 ft: Petroleum Engineer International, v. 62, 11,no. Nov, p. 36, 38

57. Sheikholeslami, B. A., Schlottmann, B., Siedel, F. A., Button, M., 1989, Drilling and production aspects of horizontal wells ithe Austin Chalk: 64th Annual SPE Technology Conference, v.,,no. 8 Oct - 11 Oct, p. 575-590

58. Stayton, J. R., Peach, S. R., 1990, Horizontal well works in Austin Chalk: American Oil & Gas Reporter, v. 33, 7,no. July, p. 29-31, 33-35

59. Stayton, R. J., Peach, S. R., 1990, Horizontal drilling enhancproduction of Austin Chalk well: IADC/SPE Drilling Conference, v.,,no. 27 Feb - 2 Mar, p. 619-626

60. Taylor, M. R., Eaton, N., 1990, Horizontal wells: part 5: formation evaluation helps cope with lateral heterogeneities: Oil & Gas Journal, v. 88, 47,no. 19 Nov, p. 56, 58, 60, 62, 64, 66



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Operations

1. Brami, J. B., 1991, Current calibration and quality control practices for selected measurement-while-drilling tools: Drilling proceedings - SPE Annual Technical Conference and Exhibiti, v. v delta,,no. 6 Oct, p. p 49-64

Pore Pressure

1. Aldred, W., Bergt, D., Rasmua, J., Voisin, B., 1989, Real-timeoverpressure detection: Oilfield Review, v. 1, 3,no. Oct, p. 17-27

2. Aldred, W., Bergt, D., Rasmus, J., Volsin, B., 1989, Real-timeoverpressure detection: Schlumberger Oilfield Review, v. 1, 3,no. Oct, p.

3. Alixant, J.-L., Desbrandes, R., 1989, Real-time pore pressureevaluation options: International Well Control Symposium/Workshop, v.,,no. 28 Nov - 29 Nov, p.

4. Alixant, J.-L., Desbrandes, R., 1989, A new approach to porepressure evaluation while drilling: Submitted to SPE Eastern Regional Meeting, v.,,no. 24 Oct - 27 Oct, p.

5. Alixant, J.-L., Desbrandes, R., 1989, Pore pressure predictiowhile drilling with PDC bits: Submitted to SPE Annual Conference, v.,,no. 8 Oct - 11 Oct, p.

6. Alixant, J.-L., Desbrandes, R., Delahaye, T., 1989, A new approach to real-time pore pressure evaluation: SPE Annual Conference, v.,,no. 24 Oct - 27 Oct, p.

7. Anon., 1980, MWD finds unexpected downhole pressure: Oil & Gas Journal, v. 78, 12,no. 24 Mar, p. 58

8. Askeland, R., 1989, New inflatable BOP (Blowout Preventer)above bit contains shallow gas kicks: Ocean Industry, v. 24, 4,no. April, p. 31,33,34

9. Bellotti, P., Gerard, R. E., 1976, Instantaneous log indicates porosity and pore pressure: World Oil, v. 183, 5,no. Oct, p. 90-94

10. Bourgoyne, A. T., Jr., Myers, G. M., Rizer, J. A., 1971, Porosand pore pressure logs: Drilling Contractor, v. 27, 4,no. May-June, p. 36-41, 44-45

11. Bourgoyne, A. T., Jr., Young, F. S., Jr., 1973, The use of drillability logs for formation evaluation and abnormal pressurdetection: 14th Annual SPWLA Logging Symposium, v.,,no., p.



of ure

.,

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12. Bryant, T. M., 1989, A dual shale pore pressure detection technique: SPE/IADC Drilling Conference, v.,,no. 28 Feb - 3 Mar, p.

13. Bryant, T. M., Grosso, D. S., Wallace, S. N., 1990, Gas influxdetection using MWD (Measurement While Drilling) technology: IADC/SPE Drilling Conference, v.,,no. 27 Feb - 2 Mar, p. 515-529

14. Cook, J. M., Sheppard, M. C., Houwen, O. H., 1990, Effects strain rate and confining pressure on the deformation and failof shale: IADC/SPE Drilling Conference, v.,,no. 27 Feb - 2 Mar, p. 291-296

15. Cook, R. L., Nicholson, J. W., Sheppard, M. C., Westlake, W1989, First real time measurements of downhole vibrations, forces, and pressures used to monitor directional drilling operations: SPE/IACD Drilling Conference, v.,,no. 28 Feb - 3 Mar, p. 283-290

16. Corre, B., Eymard, R., Guenot, A., 1984, A numerical computation of temperature distribution in a wellbore while drilling: 59th Annual SPE of AIME Technology Conference, v.,,no. 16 Sept - 19 Sept, p.

17. Daw, R. N., Mercer, R. F., Myers, D. L., 1975, Overpressure detection and control at Imp Immerk B-48 using a wellsite mugas detector: 16th Annual SPWLA Logging Symposium, v.,,no., p.

18. Desbrandes, R., Bourgoyne, A. T., Jr., 1987, MWD (Measurement While Drilling) monitoring of gas kicks ensuressafer drilling: Petroleum Engineer International, v. 59, 7,no. July, p. 46-52

19. Fertl, W. H., 1975, Detection and evaluation of abnormal formation pressures from drilling and geophysical well loggingparameters: International Hydrocarbon Exploration, Drilling & Production Technology Symposium. Today's State of the Art., v.,,no., p. 185-190

20. Gerard, R. E., 1977, Sigmalog tells pressure, porosity while drilling: Oil & Gas Journal, v. 75, 31,no. 1 Aug, p. 99-103

21. Haland, O., 1989, 34/10-20 High pressure drilling experience4th Norwegian Petroleum Society N. Europe Drilling Conference, v.,,no. 30 Oct - 1 Nov, p.

22. Hauck, M. L., et al., 1986, Quantitative computer-based porepressure determination from MWD data: AAPG, Houston GeoTech `86, v.,,no. 21 Sept - 23 Sept, p. 84-91



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,

ore-

23. Holbrook, P., 1989, An accurate rock mechanics approach topore pressure/fracture gradient prediction: International Well Control Symposium/Workshop, v.,,no. 28 Nov - 29 Nov, p. 181-197

24. Holbrook, P., Hauck, M. L., 1987, A petrophysical-mechanicamath model for real time well-site pore pressure/fracture gradiprediction: SPE Annual Fall Meeting, v.,,no. 27 Sept - 30 Sept, p

25. Holbrook, P. H., 1989, A new method for predicting fracture propagation pressure from MWD or wireline data: SPE Annual Conference, v.,,no. 8 Oct - 11 Oct, p.

26. Holbrook, P. W., 1989, A new method for predicting fracture propagation pressure from MWD (Measurement While Drillingor wireline log data: 64th Annual SPE Technology Conference, v.,,no. 8 Oct - 11 Oct, p. 475-487

27. Hornung, M. L., 1990, Kick prevention, detection, and controplanning and training guidelines for drilling deep high-pressurgas wells: IADC/SPE Drilling Conference, v.,,no. 27 Feb - 2 Mar, p. 665-678

28. Kozik, H. G., Ritch, H. J., 1971, Petrophysical study of overpressured sandstone reservoirs, Vicksburg formation,McAllen Ranch Field, Hidalog County, Texas: 12th Annual SPWLA Logging Symposium, v.,,no., p.

29. Lesso, W. G., Jr., Burgess, T. M., 1986, Pore pressure and porosity from MWD (Measurement While Drilling) measurements: IADC/SPE Drilling Conference, v.,,no. 10 Feb - 12 Feb, p.

30. McClendon, R., Rehm, B., 1971, Measurement of formation pressure from drilling data: 46th Annual SPE of AIME Fall Meeting, v.,,no., p.

31. Pilkington, P. E., 1988, Uses of pressure and temperature daexploration and new developments in overpressure detectionJournal of Petroleum Technology, v. 40, 5,no. May, p. 543-549

32. Ramsey, M. S., Robinson, L. H., Miller, J. F., Morrison, M. E.1983, Bottomhole pressures measured while drilling: IADC/SPE Drilling Conference, v.,,no. 20 Feb - 23 Feb, p. 435-444

33. Rasmus, J., Voison, B., 1989, A framework to estimate pore pressures in real time: International Well Control Symposium/Workshop, v.,,no. 28 Nov - 29 Nov, p. 159-181

34. Rasmus, J. C., Stepehns, D. M., Gray, R., 1991, Real-time ppressure evaluation from MWD/LWD measurements and



hile

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n: t al.,

drilling-derived formation strength: SPE Drilling Engineering, v. v6, n4,no. Dec, p. p 264-272

35. Rasmus, J. C., Stephens, D. M. R. G., 1990, Real-time pore pressure evaluation utilizing MWD/LWD (Measurement WhileDrilling/Logging While Drilling) measurements and drilling-derived formation strength: 65th Annual SPE Technology Conference, v.,,no. 23 Sept - 26 Sept, p. 431-442

36. Robinson, L. H., 1982, Pressure measurements downhole wdrilling: Natural Resources Council Technology for Measurement While Drilling Symposium, v.,,no. 22 Oct - 23 Oct, p. 63-85

37. Rogers, L., 1966, Shale-density log helps detech overpressuOil & Gas Journal, v. 64, 37,no. 12 Sept, p. 126-127, 130

38. Stevens, B., 1977, How to monitor pressure indicators in a problem location: Drilling , v. 38, 9,no. June, p. 42,44

39. Taylor, K. O., 1975, Use of automated logging units for predicting abnormally pressured formations and well correlatio22nd Annual Southwestern Petroleum Short Course Assn., eMeeting, v.,,no., p. 151-158

40. Thompson, M., Burgess, T. M., 1985, The prediction of interpretation of downhole mud temperature while drilling: 60th Annual SPE of AIME Technology Conference, v.,,no. 22 Sept - 25 Sept, p.

41. Vestavik, O. M., Aas, B., Podio, A. L., 1990, Downhole gas detection method in drilling fluids: IADC/SPE Drilling Conference, v.,,no. 27 Feb - 2 Mar, p. 497-503

42. Zoeller, W. A., 1983, Pore pressure detection from MWD gamma ray: SPE Annual Fall Meeting, v.,,no. 5 Oct - 8 Oct, p.

43. Zoeller, W. A., 1984, Determine pore pressures from MWD (Measurement While Drilling) gamma ray logs: World Oil, v. 198, 4,no. March, p. 97-102



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Vertical Seismic Profile

1. Brodsky, P. A., Molchanov, A. A., 1989, Modern technology ogeophysical study of super-deep boreholes: 28th International Geology Congress, v.,,no. 9 July - 19 July, p.

2. Drumheller, D. S., 1989, Acoustical properties of drill strings:Acoustic Society America, v. 85, 3,no. Mar, p. 1048-1064

3. Jorden, J. R., 1981, The use of data from Measurement WhilDrilling in seismic calibration: Natural Resources Council Technology for Measurement While Drilling Symposium, v.,,no. 22 Oct - 23 Oct, p. 107-130

4. Klaveness, A., 1989, Emerging technology in borehole geophysics with multiple applications in drilling, production, exploration, and enhanced oil recovery: 21st Annual SPE, et al., Offshore Technology Conference (OTC`89), v.,,no. 1 May - 4 May, p. 507-514

5. Ostebo, R., Musaeus, S. U., Bellamy, L., Beyer, T., 1989, Successfullness of shallow gas seismic predictions - a case history: Norwegian Petroleum Society Shallow Gas & Leaky Reservoirs Conference, v.,,no. 10 Apr - 11 Apr, p.

6. Rector, J. W., Marion, B. P., Widrow, B., 1988, Use of drill-bitenergy as a downhole seismic source: 58th Annual Society Exploration Geophysics International Meeting, v.,,no. 30 Oct - 3 Nov, p. 161-164

7. Rector, J. W., III, 1989, Real Time inverse VSP using the drill as a downhole seismic source: SAID, 12th Logging International Symposium, v.,,no. Oct, p. 24, 25, 26, 27

8. Rector, J. W., III, Marion, B. P., 1988, Using the drill bit as a downhole source for real time, inverse VSPS: Southeastern Geophysical Society Reflections, v.,,no. Nov, p.

9. Rector, J. W., III, Marion, B. P., 1989, Extending VSP (VerticSeismic Profiling) to 3-D and MWD (Measurement While Drilling): using the drill bit as downhole seismic source: Oil & Gas Journal, v. 87, 25,no. 19 June, p. 55-58

10. Rector, J. W., III, Marion, B. P., 1989, MWD VSP (Measurement While Drilling Vertical Seismic Profiling) and checkshot surveys using the drill bit as a downhole energy source: 21st Annual SPE, et al., Offshore Technology Conferen(OTC`89), v.,,no. 1 May - 4 May, p. 497-506



•Notes•


baker hughes inteq's guide to measurement while drilling information guide

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