under-balanced drilling fluids

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Candidate Candidate Selection Selection Harold Vance Department of Petroleum Engineering

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Page 1: Under-Balanced Drilling Fluids

Candidate Candidate SelectionSelection

Harold Vance Department of Petroleum Engineering

Page 2: Under-Balanced Drilling Fluids

Under-Balanced Under-Balanced FluidsFluids

•Air (NAir (N22, , Gas)Gas)•MistMist•GaseatedGaseated•FoamFoam•Oil Oil •WaterWater•MudMud

Harold Vance Department of Petroleum Engineering

Page 3: Under-Balanced Drilling Fluids

Subjects Covered

• Candidate SelectionCandidate Selection• Flow DrillingFlow Drilling• AeratedAerated• FoamFoam• Air/Gas/NAir/Gas/N22

• CompletionsCompletions

Harold Vance Department of Petroleum Engineering

Page 4: Under-Balanced Drilling Fluids

Reasons for UB DrillingReasons for UB Drilling

1.1. Limit lost circulation Limit lost circulation 2.2. Improve drilling rate Improve drilling rate 3.3. Avoid differential Avoid differential

stickingsticking 4.4. Protect reservoir Protect reservoir

Other benefits are not Other benefits are not reasons.reasons.

Harold Vance Department of Petroleum Engineering

Page 5: Under-Balanced Drilling Fluids

ResultsResults

Improve the rate of Improve the rate of return on investment.return on investment.

(Broadened Scope)(Broadened Scope)

Harold Vance Department of Petroleum Engineering

Page 6: Under-Balanced Drilling Fluids

Historical PerspectiveHistorical Perspective

Candidate SelectionCandidate Selection

Harold Vance Department of Petroleum Engineering

Page 7: Under-Balanced Drilling Fluids

Cable ToolsCable Tools

• The first The first underbalanced drillers.underbalanced drillers.

• No skin damage. No skin damage. • Great production. Great production.

Harold Vance Department of Petroleum Engineering

Page 8: Under-Balanced Drilling Fluids

UB HistoryUB History

• 1938 - California Gas Drilling.1938 - California Gas Drilling.• 1948 - Aerated, Big Lake Texas.1948 - Aerated, Big Lake Texas.• 1960 - AEC Foam, Nuclear Holes.1960 - AEC Foam, Nuclear Holes.• 1965 - Aerated U.S.1965 - Aerated U.S.• 1968 - Chevron Foam, California.1968 - Chevron Foam, California.• 1986 - Aerated Canada.1986 - Aerated Canada.• 192? - Russia, Where? What?192? - Russia, Where? What?

Harold Vance Department of Petroleum Engineering

Page 9: Under-Balanced Drilling Fluids

Underbalanced Drilling AreasUnderbalanced Drilling Areas20002000

Lost Circulation. Drilling RateReservoir ProtectionGeothermal

Harold Vance Department of Petroleum Engineering

Page 10: Under-Balanced Drilling Fluids

Number of Underbalanced WellsNumber of Underbalanced Wellsin Canadain Canada

30120

230330

525

1500

00

200200

400400

600600

800800

10001000

12001200

14001400

16001600

Tota

l N

um

ber

of

Wells

Tota

l N

um

ber

of

Wells

19921992 19931993 19941994 19951995 19961996 19971997

YearYearHarold Vance Department of Petroleum Engineering

Page 11: Under-Balanced Drilling Fluids

New SubjectNew SubjectUnderbalance Fluids Underbalance Fluids

SummarySummary

Harold Vance Department of Petroleum Engineering

Page 12: Under-Balanced Drilling Fluids

Drilling Fluid DensitiesDrilling Fluid Densities

Air

Beg

in W

eigh

ted

Mud

Nat

ive

Cla

y &

Wat

ers

SaturatedSalt W

ater

Gel and W

ater

Stable Foam

Mist

Weighted Mud (Barite)

unds per Gallon

Poun

ds P

er

10.478

10.8

75 11.183

152

.02

.3

Types of Drilling Fluids and Their Relative DensitiesTypes of Drilling Fluids and Their Relative Densities

1.0

2.0

2.3

0.5

.4

0.002

0

1.2

Harold Vance Department of Petroleum Engineering

Types of Drilling Fluids and Their Relative Types of Drilling Fluids and Their Relative DensitiesDensities

Page 13: Under-Balanced Drilling Fluids

Categories of UB DrillingCategories of UB Drilling

• Air and gas drilling.Air and gas drilling.Mist drilling.Mist drilling.

• Foam drilling.Foam drilling.• Gaseated drilling.Gaseated drilling.• Flow drilling.Flow drilling.

Harold Vance Department of Petroleum Engineering

Page 14: Under-Balanced Drilling Fluids

Gas DrillingGas Drilling

• First commercial UB drilling First commercial UB drilling was with gas in the U.S. was with gas in the U.S. (1940’s)(1940’s)

Harold Vance Department of Petroleum Engineering

Page 15: Under-Balanced Drilling Fluids

Gas DrillingGas DrillingCommon Drilling GasesCommon Drilling Gases

• Air.Air.• Natural gas.Natural gas.• Nitrogen.Nitrogen.• Engine exhaust (Nitrogen).Engine exhaust (Nitrogen).

Harold Vance Department of Petroleum Engineering

Page 16: Under-Balanced Drilling Fluids

Gas Drilling,Gas Drilling, Producing 3MM SCF/day Producing 3MM SCF/day

Harold Vance Department of Petroleum Engineering

Page 17: Under-Balanced Drilling Fluids

First Widespread use came with First Widespread use came with development of portable air development of portable air

compressors.compressors.

Western Air Drilling, 1954Western Air Drilling, 1954

Harold Vance Department of Petroleum Engineering

Page 18: Under-Balanced Drilling Fluids

Advantages of Gas Advantages of Gas DrillingDrilling

• Increase drilling rate.Increase drilling rate.• No lost circulation*No lost circulation*• No differential sticking.No differential sticking.• Minimal reservoir damage.Minimal reservoir damage.

Harold Vance Department of Petroleum Engineering

Page 19: Under-Balanced Drilling Fluids

Problems with Gas Problems with Gas DrillingDrilling

• Water.Water.• Washouts, especially in Washouts, especially in

coal.coal.• Corrosion.Corrosion.• Downhole fires with air.Downhole fires with air.• Crooked hole.Crooked hole.

Harold Vance Department of Petroleum Engineering

Page 20: Under-Balanced Drilling Fluids

Air/Mist DrillingAir/Mist Drilling

• Water & detergent is added Water & detergent is added to air (or gas) when the hole to air (or gas) when the hole becomes damp or when it is becomes damp or when it is too washed out to lift the too washed out to lift the cuttings.cuttings.

• Water added is normally Water added is normally between 5 bbl/hr to 10 bbl/hr between 5 bbl/hr to 10 bbl/hr (0.8 m (0.8 m33/hr to 1.5 m/hr to 1.5 m33/hr). /hr).

Harold Vance Department of Petroleum Engineering

Page 21: Under-Balanced Drilling Fluids

Categories of UB DrillingCategories of UB Drilling

• Air and gas drilling.Air and gas drilling.• Foam drilling.Foam drilling.• Gaseated drilling.Gaseated drilling.• Flow drilling.Flow drilling.

Harold Vance Department of Petroleum Engineering

Page 22: Under-Balanced Drilling Fluids

Foam DrillingFoam Drilling

Harold Vance Department of Petroleum Engineering

Page 23: Under-Balanced Drilling Fluids

FOAMFOAMHas the greatest Has the greatest

potentialpotential of of

any of the “Light” any of the “Light” fluids.fluids.

Harold Vance Department of Petroleum Engineering

Page 24: Under-Balanced Drilling Fluids

Advantages of Foam Advantages of Foam DrillingDrilling

• Great lifting capacity.Great lifting capacity.• Controllable BHP.Controllable BHP.• Increase drilling rate.Increase drilling rate.• No lost circulation*No lost circulation*• No differential sticking.No differential sticking.• Minimal reservoir Minimal reservoir

damage.damage.Harold Vance Department of Petroleum Engineering

Page 25: Under-Balanced Drilling Fluids

Problems with Foam Problems with Foam DrillingDrilling

• Complex mixture-Hard to get a Complex mixture-Hard to get a proper mixture and maintain it proper mixture and maintain it properly.properly.

• Disposal/Storage.Disposal/Storage.• Cost.Cost.

Harold Vance Department of Petroleum Engineering

Page 26: Under-Balanced Drilling Fluids

Categories of UB DrillingCategories of UB Drilling

• Air and gas Air and gas drilling.drilling.

• Foam drilling.Foam drilling.• Gaseated drilling.Gaseated drilling.• Flow drilling.Flow drilling.

Harold Vance Department of Petroleum Engineering

Page 27: Under-Balanced Drilling Fluids

Gaseated DrillingGaseated Drilling

• Gaseated or aerated drilling Gaseated or aerated drilling uses a mixture of fluid and uses a mixture of fluid and gas.gas.

• Gas may generally be any gas.Gas may generally be any gas.• Fluid may be from oil to water Fluid may be from oil to water

to drilling mud.to drilling mud.• No binding agent is used No binding agent is used

(foamer).(foamer).

Harold Vance Department of Petroleum Engineering

Page 28: Under-Balanced Drilling Fluids

Gaseated SeparatorGaseated Separator

Harold Vance Department of Petroleum Engineering

Page 29: Under-Balanced Drilling Fluids

Advantages Advantages of Gaseated Drillingof Gaseated Drilling

• Increase drilling rate.Increase drilling rate.• No lost circulation*No lost circulation*• No differential sticking.No differential sticking.• Minimal reservoir Minimal reservoir

damage.damage.

Harold Vance Department of Petroleum Engineering

Page 30: Under-Balanced Drilling Fluids

Problems Problems with Gaseated Drillingwith Gaseated Drilling

• Surging (causing Surging (causing overpressures or overpressures or caving).caving).

• Corrosion (not with Corrosion (not with nitrogen).nitrogen).

• Hole caving.Hole caving.

Harold Vance Department of Petroleum Engineering

Page 31: Under-Balanced Drilling Fluids

Categories of UB DrillingCategories of UB Drilling

• Air and gas drilling.Air and gas drilling.• Foam drilling.Foam drilling.• Gaseated drilling.Gaseated drilling.• Flow drilling.Flow drilling.

Harold Vance Department of Petroleum Engineering

Page 32: Under-Balanced Drilling Fluids

Flow DrillingFlow Drilling

Harold Vance Department of Petroleum Engineering

Page 33: Under-Balanced Drilling Fluids

Flow DrillingFlow Drilling

Conventional Mud Used in an Conventional Mud Used in an Underbalanced ConditionUnderbalanced Condition

Harold Vance Department of Petroleum Engineering

Page 34: Under-Balanced Drilling Fluids

Advantages of Flow Advantages of Flow DrillingDrilling

• Uses regular mud Uses regular mud system.system.

• Least expensive way of Least expensive way of UB drilling.UB drilling.

• No lost returns.No lost returns.• No differential sticking.No differential sticking.• Improved ROP.Improved ROP.

Harold Vance Department of Petroleum Engineering

Page 35: Under-Balanced Drilling Fluids

Problems with Flow Problems with Flow DrillingDrilling

• Limited ability to reduce Limited ability to reduce annular pressure below annular pressure below “normal” reservoir pressures.“normal” reservoir pressures.

• Drilling with a constant well Drilling with a constant well flow or potential of well flow.flow or potential of well flow.

Harold Vance Department of Petroleum Engineering

Page 36: Under-Balanced Drilling Fluids

• All have problems.All have problems.• Nothing works all the Nothing works all the

time.time.• UB does not improve UB does not improve

production all of the time.production all of the time.

All Good IdeasAll Good Ideas

Harold Vance Department of Petroleum Engineering

Page 37: Under-Balanced Drilling Fluids

COMMENTS!!COMMENTS!!

Underbalanced Drilling Underbalanced Drilling BenefitsBenefits

Candidate SelectionCandidate Selection

Harold Vance Department of Petroleum Engineering

Page 38: Under-Balanced Drilling Fluids

• New processes involve New processes involve risk.risk.

• Budget enough money.Budget enough money.• Don’t promise too much.Don’t promise too much.

Underbalanced DrillingUnderbalanced Drilling

Harold Vance Department of Petroleum Engineering

Page 39: Under-Balanced Drilling Fluids

Have at Least One Have at Least One Good Good Economic Economic

ReasonReason or or

Technical ReasonTechnical Reason

Harold Vance Department of Petroleum Engineering

Page 40: Under-Balanced Drilling Fluids

Remember the Learning Remember the Learning Curve !!!!Curve !!!!

Harold Vance Department of Petroleum Engineering

Page 41: Under-Balanced Drilling Fluids

UB Drilling UB Drilling ApplicationsApplications

Harold Vance Department of Petroleum Engineering

Page 42: Under-Balanced Drilling Fluids

UB Drilling ApplicationsUB Drilling Applications

• Drilling.Drilling.• Lost returns.Lost returns.• Drilling rate.Drilling rate.• Differential pressure Differential pressure

sticking.sticking.• Limited water.Limited water.• Reservoir protection.Reservoir protection.

Harold Vance Department of Petroleum Engineering

Page 43: Under-Balanced Drilling Fluids

Lost ReturnsLost Returns

• Reduce the mud density.Reduce the mud density.• Don’t add junk.Don’t add junk.

Harold Vance Department of Petroleum Engineering

Page 44: Under-Balanced Drilling Fluids

Lost Circulation Lost Circulation CandidatesCandidates

• Permeability > 1,000 md.Permeability > 1,000 md.• Large fractures (>100 micron Large fractures (>100 micron

opening).opening).• Vugular porosity.Vugular porosity.• Overbalanced > 1,000 psi with Overbalanced > 1,000 psi with

conventional fluids.conventional fluids.

Harold Vance Department of Petroleum Engineering

Page 45: Under-Balanced Drilling Fluids

70

60

50

40

30

20

10

00 1000 2000 3000 4000

AUSTIN CHALKAUSTIN CHALK

MANCOS SHALEMANCOS SHALE

COLTON SANDSTONECOLTON SANDSTONE

DR

ILLIN

G R

ATE (

ft/ h

r)

7-7/8 TRICONE BIT7-7/8 TRICONE BIT30,000 lbs. WOB30,000 lbs. WOB60 RPM60 RPM

pp

bp

DIFFERENTIAL PRESSURE (psi)

Increased Drilling RateIncreased Drilling RateEffect of Differential Effect of Differential

PressurePressure

Harold Vance Department of Petroleum Engineering

Page 46: Under-Balanced Drilling Fluids

-500 0 +500 +1000

Drilling Rate-UBDrilling Rate-UBEffect of Differential Effect of Differential

PressurePressure

Bit Bit FlounderFlounder

Perfect Perfect CleaningCleaning

Harold Vance Department of Petroleum Engineering

DR

ILLIN

G R

ATE (

ft/ h

r)

DIFFERENTIAL PRESSURE (psi)

p

pb

p

Page 47: Under-Balanced Drilling Fluids

Hard Rock & Crooked Hard Rock & Crooked HoleHole

• Air Hammer.Air Hammer.• Pendulum.Pendulum.

Harold Vance Department of Petroleum Engineering

Page 48: Under-Balanced Drilling Fluids

Differential Pressure Differential Pressure StickingSticking

DRILL PIPEDRILL PIPE

FILTER CAKEFILTER CAKE

DRILL COLLARDRILL COLLAR

, K, K

PPff

PHPH

PH > PPH > Pff

Harold Vance Department of Petroleum Engineering

Page 49: Under-Balanced Drilling Fluids

Limited WaterLimited Water

Desert & Semi-Arid RegionsDesert & Semi-Arid RegionsAlgeriaAlgeriaSouth YemenSouth YemenLibyaLibyaSW United StatesSW United States

Harold Vance Department of Petroleum Engineering

Page 50: Under-Balanced Drilling Fluids

UB Drilling Applications UB Drilling Applications (2)(2)

• Formation damage avoidance.Formation damage avoidance.Skin damage.Skin damage.Fluid-fluid sensitivity.Fluid-fluid sensitivity.Fluid-formation sensitivity.Fluid-formation sensitivity.Depleted zones.Depleted zones.

Harold Vance Department of Petroleum Engineering

Page 51: Under-Balanced Drilling Fluids

Formation DamageFormation Damage

Harold Vance Department of Petroleum Engineering

Page 52: Under-Balanced Drilling Fluids

• Slow drilling rate.Slow drilling rate.• Lost returns.Lost returns.• Differential pressure Differential pressure

sticking.sticking.• Reservoir damage.Reservoir damage.

Depleted ZonesDepleted Zones

Harold Vance Department of Petroleum Engineering

Page 53: Under-Balanced Drilling Fluids

Skin DamageSkin Damage

Harold Vance Department of Petroleum Engineering

Reservoir Reservoir CoreCore

Filter CakeFilter Cake

Page 54: Under-Balanced Drilling Fluids

Skin Damage Due to Skin Damage Due to Filter Cake and Mud SolidsFilter Cake and Mud Solids

10 micron 10 micron pore throatpore throat1-3 micron 1-3 micron solidssolids

10 micron pore 10 micron pore throatthroat1 micron & 1 micron & smaller solidssmaller solids

10 micron pore 10 micron pore throatthroat10 micron 10 micron solids & somesolids & somesmaller solidssmaller solids

Effective Effective ExternalExternal

Filtrate SealFiltrate Seal

Internal Internal PlugginPluggin

gg

Ineffective Ineffective ExternalExternalSeal for Seal for

SmallSmallFines & Fines & FiltrateFiltrate

10u10u

Harold Vance Department of Petroleum Engineering

Page 55: Under-Balanced Drilling Fluids

Skin DamageSkin DamageAvoidance TechniquesAvoidance Techniques

•UB DrillingUB Drilling•Non-Invasive Mud CakeNon-Invasive Mud Cake•Ultra Clean Drill-in FluidUltra Clean Drill-in Fluid

Harold Vance Department of Petroleum Engineering

Page 56: Under-Balanced Drilling Fluids

Fluid Fluid

SensitivitySensitivity1.1. Fluid-Formation Reaction (Shale Instability) Fluid-Formation Reaction (Shale Instability)

Fluid-Fluid Reaction Fluid-Fluid Reaction (Emulsions)(Emulsions)

2.2.

Harold Vance Department of Petroleum Engineering

Page 57: Under-Balanced Drilling Fluids

Mechanism for Formation Mechanism for Formation BlockingBlocking(Bennion, 1995)(Bennion, 1995)

Non Non WettingWettingPhasePhase

Non Non WettinWettin

gg

Non Non WettingWettingPhasePhase

FinesFinesWettingWettingPhasePhase

Case 1 Non-Wetting

phase in motion-

minimal fines migration

Case 2 Case 2 Wetting phaseWetting phase

in motion -in motion -potential for fines potential for fines

migrationmigration

Harold Vance Department of Petroleum Engineering

Page 58: Under-Balanced Drilling Fluids

FormationFormation Damage - Fractured Formations Damage - Fractured Formations

Fracture PluggingFracture Plugging

Harold Vance Department of Petroleum Engineering

Page 59: Under-Balanced Drilling Fluids

UB Drilling in Fractured UB Drilling in Fractured ReservoirsReservoirs

GravityGravityDisplacementDisplacement

Fluid Fluid BalanceBalanceor Micro or Micro FractureFracture

21 Drilling FluidDrilling FluidProduced FluidProduced Fluid

No Invasion of“Top” FracturesWhile Underbalanced

Harold Vance Department of Petroleum Engineering

Page 60: Under-Balanced Drilling Fluids

Potential Formation DamagePotential Formation Damage Mechanism in Different Sand Reservoir Mechanism in Different Sand Reservoir

TypesTypes

DamageMechanism F

luid

-Flu

idIn

com

pati

bilit

y

Rock-F

luid

Incom

pati

bilit

y

Solid

sIn

vasio

n

Ph

ase

Tra

pp

ing

Ch

em

ical

Ad

sorp

tion

Fin

es

Mig

rati

on

Bio

log

ical

Dam

ag

e

Eff

ect

of

Hig

hO

verb

ala

nced

HomogenousSand-Clean

HomogenousSand-Dirty

LaminatedSand-Clean

LaminatedSand-Dirty

UnconsolidatedSand

Fractured SandPerm-Matrix

Probable Possible Probable Possible Unlikely Unlikely Harold Vance Department of Petroleum Engineering

Page 61: Under-Balanced Drilling Fluids

DamageMechanism F

luid

-Flu

idIn

com

pati

bilit

y

Rock-F

luid

Incom

pati

bilit

y

Solid

sIn

vasio

n

Ph

ase

Tra

pp

ing

Ch

em

ical

Ad

sorp

tion

Fin

es

Mig

rati

on

Bio

log

ical

Dam

ag

e

Eff

ect

of

Hig

hO

verb

ala

nced

HomogenousCarbonate

Fractured CarbonateImpermeable Matrix

VugularCarbonate

Fractured CarbonatePermeable Matrix

Harold Vance Department of Petroleum Engineering

Potential Formation DamagePotential Formation Damage Mechanism in Different Sand Reservoir Mechanism in Different Sand Reservoir

TypesTypes

Probable Possible Probable Possible Unlikely Unlikely

Fractured SandLow Perm Matrix

Page 62: Under-Balanced Drilling Fluids

Underbalanced Drilling Underbalanced Drilling LimitationsLimitations

Candidate SelectionCandidate Selection

Harold Vance Department of Petroleum Engineering

Page 63: Under-Balanced Drilling Fluids

UB LimitsUB Limits

• UB is not an UB is not an enhancement technique.enhancement technique.

• Mud column pressure is Mud column pressure is not a seal against:not a seal against: Well kick.Well kick. Broken or fractured formation.Broken or fractured formation. Weak formations.Weak formations. Heaving shale.Heaving shale.

Harold Vance Department of Petroleum Engineering

Page 64: Under-Balanced Drilling Fluids

Underbalanced Underbalanced ProblemProblem

ROTATING BOPs

SOLID/LIQUID/GASSEPARATION

COMPRESSOR / N2

COST

CORROSION

VIBRATIONS

HYDRAULIC CALCULATIONS

CUTTINGS LIFTING

FLUID INFLUX

BOREHOLESTABILITY

MWD TRANSMISSION

HIGH TORQUE/DRAG

UNDERBALANCEDCOMPLETION

FIRE/EXPLOSIONS

Harold Vance Department of Petroleum Engineering

Page 65: Under-Balanced Drilling Fluids

If a reservoir will If a reservoir will

not produce not produce

without fracturing without fracturing

it is probably a it is probably a

poor UB prospect.poor UB prospect.

Harold Vance Department of Petroleum Engineering

Page 66: Under-Balanced Drilling Fluids

WarningWarning

A poor prospect can prove failure. You must gamble with a well that can succeed.

Harold Vance Department of Petroleum Engineering

Page 67: Under-Balanced Drilling Fluids

The “Absolute” Rule for The “Absolute” Rule for UB OperationsUB Operations

……IT’S NOT WHAT YOU KNOW IT’S NOT WHAT YOU KNOW THAT HURTS YOU.THAT HURTS YOU.

……IT’S WHAT YOU KNOW THAT’S IT’S WHAT YOU KNOW THAT’S NOT TRUE!NOT TRUE!

Harold Vance Department of Petroleum Engineering

Page 68: Under-Balanced Drilling Fluids

The No-Go ScreenThe No-Go ScreenThe No-Go ScreenThe No-Go Screen

If the following occurs within the If the following occurs within the open hole section:open hole section:

DON’T DRILL UNDERBALANCEDDON’T DRILL UNDERBALANCED

1. Geopressured shales1. Geopressured shales2. Steeply dipping fractured 2. Steeply dipping fractured formationsformations3. Thick broken coals 3. Thick broken coals 4. What about sands? - not 4. What about sands? - not sandstonesandstone

Harold Vance Department of Petroleum Engineering

Page 69: Under-Balanced Drilling Fluids

Primary Cause of Well Primary Cause of Well Bore CollapseBore Collapse

Primary Cause of Well Primary Cause of Well Bore CollapseBore Collapse

• NATURAL CAUSESNATURAL CAUSESFractured or Faulted ZonesFractured or Faulted ZonesHigh Pore Pressure High Pore Pressure

(Geopressure)(Geopressure)Weak, Low Strength RocksWeak, Low Strength RocksHigh in Situ StressesHigh in Situ Stresses

Harold Vance Department of Petroleum Engineering

Page 70: Under-Balanced Drilling Fluids

Primary Causes of Well Primary Causes of Well Bore CollapseBore Collapse

INDUCED PROBLEMSINDUCED PROBLEMSPressure SurgesPressure SurgesWetted ShalesWetted Shales

Harold Vance Department of Petroleum Engineering

Page 71: Under-Balanced Drilling Fluids

WELLSTAB - MEI Wellbore Stability ModelMechanical/Chemical Stability Design

Multi-Depth AnalysisMicrosoft Office Report

Harold Vance Department of Petroleum Engineering

Page 72: Under-Balanced Drilling Fluids

ENDEND

Harold Vance Department of Petroleum Engineering