borehole properties analysis - schlumberger
TRANSCRIPT
EnvironmentalMeasurement Sonde
Borehole PropertiesAnalysis
Applications■ Calculation of borehole
radius and cement volume
■ Stress analysis and boreholestability evaluation
■ Automatic analysis ofborehole shape
■ Environmental correctionand depth matching ofother measurements
Benefits■ Precise borehole-shape
evaluation to determinedrilling performance
■ Accurate estimation ofcement volume to optimizecementing cost
■ Combined operations withother measurements savesrig time
■ Real-time environmentalcorrections for other loggingtools to yield accurate results
■ Real-time depth matchingof other logging tool data toenhance log interpretation
Features■ Six independent borehole
radii measurements
■ Mud temperature, mudresistivity and toolacceleration measurements
■ Centralized or eccentralizedoperation
■ Modular design to suitindividual application needs
■ Flexible configurationand setup
■ Combinable with mostformation evaluation tools
New dimension for borehole evaluationThe Environmental MeasurementSonde (EMS) dramatically increasesthe ability to determine the preciseshape of the borehole. Supported bythe MAXIS* Multitask Acquisition andImaging System, the EMS tool usessix independent arms to make calipermeasurements around the borehole.These caliper readings provide exten-sive drilling and petrophysical infor-mation. Using an ovality algorithm,the measurements determine the defi-nite shape of the borehole for stressanalysis studies. In addition, the EMStool measures mud resistivity, mudtemperature and acceleration alongthe tool axis for real-time environ-mental correction of downhole meas-urements.
Better borehole geometry evaluationOver a wide range of borehole sizes,the six independent arms of the EMStool precisely measure the boreholecross section to give detailed informa-tion on borehole geometry. The resultis better environmental correction ofthe imaging tool data, improved bore-hole stress analysis and more preciseestimation of the cement volume, evenif the tool is eccentered.
Improved mud resistivity measurement With multiple voltage monitoringelectrodes, the EMS mud resistivitysensor provides robust and accurate
mud resistivity measurements underadverse conditions. Even with mud-cake on the tool surface or in narrowboreholes, the EMS tool delivers reli-able and precise measurements.
Real-time environmental correctionsThe improved caliper, mud resistivityand temperature measurements allowreal-time environmental correction ofmeasurements obtained from imagingtools such as the AIT* Array InductionImager Tool, the IPL* IntegratedPorosity Lithology tool and the ARI*Azimuthal Resistivity Imager. Sincethe EMS tool is combinable with allimaging tools, environmentally cor-rected wellsite logs can be producedwithout an extra trip in the hole.
Better depth matchingThe EMS tool incorporates a singleaxial accelerometer. Data from theaccelerometer can be used to provideaccurate depth matching of the bore-hole measurements, correct tool speedand estimate hole deviation.
AdaptabilityDesigned to suit individual applicationrequirements, the EMS tool incorpo-rates three modules, the environmentalmeasurement cartridge (EMC), theenvironmental measurement sondeadapter (EMA) and the environmentalmeasurement mechanical sub (EMM).These modules can be run in different
Mudcakecoveringthe sensor
Mud resistivitymeasurement
Current path
Sensor
Boreholewall
Equipotentialsurfaces
The mud resistivity measurement is not affected by the presence of mudcake in front of the tool.
configurations depending on the toollength and data requirements. The toolcan be run centered or eccentered witheach of the six caliper arms independ-ent of each other. In conditions wheretool eccentering is crucial for othermeasurements in the same tool string,an optional fixed caliper operation isavailable that features three adjacentarms locked.
Detailed borehole geometry data The six independent caliper readingssupply data for both drilling and petro-physical studies. An algorithm, basedon all six oval-radii measurements,gives the best-fit ovality and providesborehole geometry with long- andshort-axis diameters, their orientationand the tool arm positions.
The computed long- and short-axisdiameters are more precise than rawmeasurements, which may be affectedby tool eccentralization and boreholeovality. The log presentation can betailored to specific needs, and the loganswers can be customized to give agood visual indication of the boreholeprofile to enhance decision making.Precise cement volumes can also becalculated.
Digital telemetrycartridge (DTC)
Environmental measurementsonde adapter (EMA)
Environmental measurementcartridge (EMC)
Environmental measurementmechanical sub (EMM)
Other tools
DTC
EMC
EMM
Other tools
DTC
EMA
EMC
Adapter head
Other tools
DTC
EMCAdapter head
Other tools
Measurements provided
Mud resistivityTemperatureBorehole diametersTool acceleration
Borehole diametersTool acceleration
Mud resistivityTemperatureTool acceleration
Tool acceleration
The EMS tool has three modules that can be easily configured to the required measurement need and tool length limitation.
XO25
XO50
XO75
4.59
8.52
7.22
3.63
5.53 9.67
4.464.22
9.09 9.436.13
4.93 10.32
3.82
6.79 10.0713.88
4.86 6.11
7.86 8.9410.37
8.685.18
5.20 9.787.335.59
5.855.32 4.58
10.274.635.93
4.945.20 5.03
3.69
4.174.88
Depth(ft)
OvalizationLong axis diameter
10 0 10(in.)
Short axis diameter10 0 10
(in.)Bit size
10 0 10(in.)
From the EMS log, the driller can easily select the best setting depth for an openhole packer.
SMP-5883 ©Schlumberger
July 2002 *Mark of Schlumberger
www.connect.slb.com
The EMS tool has six independent arms thatprecisely gauge the borehole cross sectionover a wide range of borehole sizes.
EMS Tool Specifications
Length 14.1 ft [4.5m]Diameter 3.375 in. [85.7 mm] without caliper section
4.000 in. [101.6 mm] with caliper sectionWeight 296 lbm [133 kg]Temperature rating 175°F [350°C]Pressure rating 20,000 psi [137,895 kPa]Mud resistivity
Range 0.01 to 5 ohm-mAccuracy ±10% (0.02 to 0.5 ohm-m)
±7% (0.5 to 5.0 ohm-m)Depth of investigation 0.3 to 1.0 in. [7.62 to 25.4 mm]
Mud temperatureResolution 0.1°C (0.2°F)Accuracy ±1°C or 1% (±2°F)
CaliperMaximum diameter 40 in. [1016 mm] with extension arms
30 in. [762 mm] without extension armsResolution 0.06 in. [1.5 mm]Accuracy ±0.1-in. [2.5-mm] radius
AccelerationAccuracy +4 cm/s2 Resolution 1 cm/s2