lesson 8b introduction to ubd

8/13/2019 Lesson 8b Introduction to UBD

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Introduction toUnderbalanced

Drilling Technology(M2)


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Wellsite UBD Equipment

Camp

GeologyNitrogen

Separator

Mud Treatment

Rotating Head

UB operators


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UB DRILLING - JOBS

1997 Underbalanced Dri l l in g Jobs

Geographic Distribution

Canada

US Europe

South America

M idd le East

Far East

1998 Spears & Assoc.


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Normally Pressured Reservoirs

Applications for normal to above normalpressured reservoirs utilizing fluid systems

in a controlled flow (mudcap) drillingtechnique.

Depleted Reservoirs

Where a multi-phase circulating fluid isnecessary to achieve required Bottom HoleCirculating Pressure (BHCP) -

underbalanced or with minimal overbalance.

UBD - Types


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Barriers to UB Drilling


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REGULATORY BARRIERSto

UnderBalance DrillingThe regulators

need assurance

and details


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BARRIERS TO UB D&C

Regulatory

Lack of Standards

Lack of knowledge

Little statistical history

Concern about well controlEnvironmental questions


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OPERATORS BARRIERS

The Operatorneeds

experience andconfidence.


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OPERATORS PROBLEMS

Unfamiliar with the system

risk of the new

Lack of experienced people

Economics - Too expensive

Concern- liabilityConcern- well bore stability


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REASONS FOR UB GROWTH

There aredriving

economicreasons


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Depleted reservoirs

Awareness of skin damageLimits of lost circulation matl.

Cost of differential sticking


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Service co. competition

Trade journal publicationsHorizontal drilling

Consultants available


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TECHNICAL IMPROVEMENTS

We were notready to put all

of this togetheruntil the 1990s


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Compressor Evolution

Hammer drillsNitrogen

Increased availability

Reduced costOn site generation


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Recyclable foam systems

Better gas separators

Closed loop circulation

Hydraulics models

Improved rotating heads

Wire line wet connect


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Improved MWD

Rig assist snubbing units

Coiled tubing equipment

Non-damaging drilling fluids

Top drive


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WORKING ON

Well Control Concepts

Deployment valves

Casing Drilling

Expandable casing

Expandable sand screens

Retractable bit


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COMPLETION TECHNIQUES

Improved gravel packing fluids

Improved completion fluids

General techniqueimprovement


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Reasons for UB drilling

Lost circulation


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Lost circulation

Faster Drilling


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Lost circulation

Faster Drilling

No DifferentialSticking


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...

Reduce

ReservoirDamage


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...

Reduce

ReservoirDamage

Improve Prod.

Evaluation


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Effect of Skin on Production Rates

0

200

400

600

800

1,000

SKIN

BOPD

5 10-2 0 15-3 -1


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UBD is another tool in the toolbox,

not a Panacea.

Physical Limitation to UBD

Borehole Instability Unconsolidated Sands

Weak Formations

Geopressured Shales

Salt Beds

Inadequate Casing


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Production Limits to UBD

Permeability isso low the zone

needs to befraced.

Zones must be

isolated


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MISTFOAMLIQUID GASAERATED

LIQUID

Types of Flow Regimes


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Fluid Phase Continuity

MIST

(97-100% AIR)

FOAM

(0-97% AIR)

AIR/GAS

WATER


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GeneralizedFluid Systems


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CONTROL EQUIPMENT


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Shaffer Rotating Blow-Out Preventor

2,500 psi rotating - 5,000 psi static

Equipment - Rotating Head

Cl d L Ci l i


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Closed Loop CirculationSystem

SEPARATOR

OILTANKS

WATER

TANKS

NITROGENPUMPERS

MUD

TANKS

RIG

RIG

PUMPS

R-BOP

TOPDRIVE

SYSTEM

CATCHERS

SAMPLE

CHOKEMANIFOLD

FLARESTACK

N2/ FLUID

MIX

CUTTING

RETURN


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Choke Manifold


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Equipment - Lots More

Samplecatchers

Willis choke

Manifold

Flare

Separator200 psi vessel

Oil storage/transport

Water returned to tanks

Flare pitChoke

ChokeRig Manifold

ESD

To shale shaker

HCR


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AIR DRILLINGA brief summary


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Air Drilling

Air/Gas drilling (dust) is a technique used inareas where the formations are Dry i.e., there

is no influx of water or liquid hydrocarbons. This medium requires significant compressed

gas volumes to clean the well with averagevelocities of over 3,000 ft per minute.


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Air Drilling Dusting


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Air Drilling Benefits

Increased Rate of PenetrationReduced Formation Damage

Improves Bit PerformanceLost Circulation ControlContinuous Drill Stem Test


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Air/Dust Drilling Layout

Air Drilling Waited upon


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Air Drilling Waited uponLarge Portable Compression

Simple and convenient to drill with air inexpensively and anywhere.


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Misting

Addition of 6 to 30 bbl/hr offluid to the air stream.

Clean and lubricates the bit

Carries the cuttings to the

surface as a mist or morenormally in a modified twophase flow.


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TT96-86 42

FOAM DRILLING

Basic Comments


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Foam Drilling

The most versatile of the gas-generatedsystems.

Effective operating range from 0.2 to 0.6 s.g.

Mixture of gas phase and foaming solution.

Foam flow varies with depth in the hole.

Adjustable effective BHP.

Enhanced lifting and well bore cleaning.

A displacing medium, not a propellingmedium.


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Foam (Heading)


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Improved Hole Cleaning


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Mist or Foam Drilling Layout


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GASEATEDOR

AERATEDDRILLING


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Gaseated

Mist

TransitionWater

Gas


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Aerated Fluid

Gasification of Primary Drilling Fluid.

Initially designed as a technique to lightenmud to reduce lost circulation.

Methods Standpipe injection

Jet Sub

Parasite String Dual Casing String

As an UB fluid, it is easiest to control in smallholes.


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Small injection string run simultaneouslywith intermediate casing.

Injected gas does not affect

bit hydraulics. Injected gas does not effect

MWD

Parasite String


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Jet Sub

Similar to Parasite String

Gas induced thru drill pipe

Selective jet sizing dictatesamount of air to be injected

Jets are Similar to Bit Jets

Parallel Casing String


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Parallel Casing String(Teichrob)

N /air2

N /water2

N /air/water/oil2

89-mm (3-1/2 in.) Drill Pipe

244.5-mm (9-5/8 in.) Intermidiate Casing

177.8-mm (7 in.) Tie Back Liner

724 m MD at64 inclination

12 m Slotted

Joint

892 m MD

at 90 Inclination694 m TVD

150 m TVD, 150 m MD

Foam Cement

TD = 1,440 m MD at 90Inclination, 696 m TVD

159-mm (6-1/4 in.)Hole Diameter

o

o

o

o

o


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Aerated Fluid Layout


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Compressor/N2Cost

Rotating BOPs

Solid/Liquid/GasSeparation

Corrosion

Vibration

High Torque/Drag

Borehole StabilityMWD Transmission

Hydraulic Calculations

Cuttings Lifting

Fluid InfluxFire/Explosions

UnderbalancedCompletion

Aerated Drilling Problems


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ENDOF

INTRODUCTION

lesson 8b introduction to ubd

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