wft ubd dti 020416

7/27/2019 WFT UBD DTI 020416

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© 2002 Weatherford. All rights reserved.

Weatherford U nder Balanced S ervices

General Underbalance Presentation

to the DTI M.O.S.T.

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Presentation Content

– Underbalance Overview

– Candidate Selection – Reservoir Effects & Flow Potential

– Ultimate Recovery Factor

– Compressible Fluids

– Underbalance Equipment and Technology

– Environment & Safety

– QHSE - Systems and Processes

– Developing Technology

– Summary

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E&P Business Drivers and Value Creation

E&P DRIVERS CREATE VALUEWITH UBS

• Increase Productivity

• Enhance Well Evaluation

• Increase Reserves: (Add andRecovery/Well)

• Improve NPV (EarlyProduction)

• Reduce Drilling Cost (ROP,Fluid Losses, Diff. Sticking)

• Increase BOE Production

• Improve Cashflow - AdvanceTime

• Reduce Life Time Cost

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UB - Global Market Players

UB Market in 2002 = $500 million?

HAL

<5%

<5%

<5%

WFT

40%

50%

60%2002(est.)

Northland

40%

30%

20% 5%

~

Slb (MI)

2000

2001

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Weatherford U nder Balanced S ervicesOrganization and Foundations

INTERNATIONAL

INS

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26GLOBAL UBSGLOBAL UBS


Click to edit Master title style

USA

• Corporate Office with

Center Team (10)

• Offices: Houston, Casper,Farmington, Midland

• Engrs: 10

• Total Staff: 100

• Tech. Sales In: Houston,

Casper, Farmington, Midland• Logistics Center: Houston

• Offices: Caracas, Rio, Buenos Aires, Bogota

• Engrs: 10


• Tech. Sales In: Colombia, Venezuela,

Brazil, Argentina, Mexico

Latin America

WFT UBS Global Infrastructure - 2002

N. America

Canada

• Offices: Calgary,Nisku

• Engrs: 10

• Total Staff: 100• Tech. Sales In: Calgary,Nisku

Eastern Hemisphere

• Office: Dubai

• Engrs: 20


• Tech. Sales In: UK, Europe,Algeria, Dubai, Jakarta, Lithuania

• Logistics Center: Dubai

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Underbalanced TeamBlends Software and Hardware

CompressedGases

UBSTeam

ProjectEngineering

Planning andExecution

WellControl

CompressibleFluids and

Chemistry

SpecialtyServices

Well FlowDynamics

Simulation

Real TimeData

Acquisition

SeparationSystems andWell Testing

INFORMATIONAL

MECHANICAL

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Underbalance Overview

Where, When, Why?

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1992 - present

• 10 Variations of UBD have developed

– Air and natural gas drilling

– Flow Drilling to atmosphere (flare) – Flow Drilling to Closed System

– Mist Drilling

– Foam Drilling

– Aerated Fluid Drilling

– Mud-Cap Drilling – Snub Drilling

– Production Drilling

– Offshore use of UBD tools and technology

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Impact Of Innovation

EstimatedReduction of

Development

Costs ($/b)

TechnologyYear broadly

accepted

3D Seismic 1990 30%

DirectionalDrilling

1995 50%

Underbalanced TBD 75%

Pre-3D Seismic 0%

+20%

+25%

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WHERE• Hard Rock Formations

• Areas of Loss Circulation

• Depleted Reservoirs and Zones

• Deviation Control

• Water Sensitive Zones

• Application is Not Necessarily Just for Pay Zones

WHERE NOT

• Excessive Water Flows

• Highly Unconsolidated Formations

• Plastic Flowing Salts

• Tectonically Stressed Shales

Underbalanced Drilling

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BENEFITS - MORE OIL & GASIncrease Well Productivity

Increase Well InjectivityReduce Formation Damage

Reduce Well Stimulation

Reservoir Fluid Sensitivity

Reduce Well Costs

Potential to Reduce Porosity cut-off,leading to increased recoverable andbookable reserves

UBD can only solve skin damage and fracture plugging, it cannot change the

reservoir properties

Fracture Plugging

Pore Plugging Skin Damage

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Formation Damage

Overbalanced Drilling

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Underbalanced Drilling- HORIZONTAL

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Real Time Reservoir Investigation

• Underbalanced drilling can assist in locating andidentifying geologic features such as: fractures; tightzones; pinch outs; discontinuities; water zones; etc.

• This information can be used to determine:

– degree of reservoir heterogeneity

– optimum horizontal wellbore length

– number and orientation of future development wells

– anticipated production rates

– optimum lateral length

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0

0.25

0.5

0.75

1

1.25

1.5

1.75

2

4000 4500 5000 5500 6000 6500 7000Measured Depth (ft)

G a s P r o d u c

t i o n ( M M s c f d )

3300

3350

3400

3450

3500

3550

3600

3650

3700

T V D

( f t )

Gas Inflow

True Vertical Depth

Real-Time Inflow Mapping

Gas Production & True Vertical Depth vs. Measured Depth

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0

2

4

6

8

10

12

3700 4000 4300 4600 4900 5200 5500 5800 6100 6400Measured Depth (ft)

G

a s P r o d u c t

i o n ( M M s c f

d )

3690

3700

3710

3720

3730

3740

3750

T V

D ( f t )

Indicators of Fracture-Related Gas Inflow

Cumulative Gas Inflow

True Vertical Depth

Identification of Fracture Inflow

Gas Production & True Vertical Depth vs. Measured Depth

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• Increase Drilling Efficiency Through

Higher Rates of Penetration

• Reduce Well Costs

• Less Bit Trips

• Extends Bit Life

• Differential Sticking

• Reduce Mud Bills


BENEFITS - DRILL FASTER

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Effect of Differential Pressure on Drilling Rate

70

60

50

40

30

20

10

0

-50 0 +150

AUSTIN CHALK

MANCOS SHALE

COLTON SANDSTONE

7-7/8 TRICONE BIT30,000 # WOB

60 RPM

p p

b

p

R a

t e f t / h r

Differential Pressure PSI

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Candidate Reservoirs

• High-permeability (>1000 md) lithified sands andcarbonates

• High-permeability unconsolidated or poorly-consolidated

sands

• Macro- or micro-fractured reservoirs

• Highly-depleted reservoirs• Reservoirs prone to wetting-phase reversal

• Reservoirs with hydratable clay minerals

• Reservoirs bearing fluids that may form precipitates or emulsions

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Po

tentia lF

orm

ation

Damag e

Mech an

ism

s

(after

Benno

in,19

96)

DamageMechanism

FormationType

F l u i d - F l u i d

I n c o

m p a t i b i l i t y

R o

c k - F l u i d

I n c o

m p a t i b i l i t y

S o l i d s

I n

v a s i o n

P h a s e

T

r a p p i n g

C h e m i c a l

A b

s o r p t i o n

F i n e s

M

i g r a t i o n

B i o l o g i c a l

D

a m a g e

E f f e

c t O f H i g h

O v e r b a l a n c e

Homogeneous Sand -Clean Π Π Π Π Π Ο Π ΠHomogeneous Sand -Dirty Π Ρ Π Π Ρ Ρ Π ΠLaminated Sand - Clean Π Π Π Π Π Ο Π ΠLaminated Sand - Dirty Π Ρ Π Π Ρ Ρ Π ΠUnconsolidated Sand Π Π Ρ Ο Π Π Π ΡFractured SandPermeable Matrix Π Π Ρ Π Π Π Π ΡFractured SandLow Permeability Matrix Π Ο Ρ Π Π Ο Π ΡHomogeneous Carbonate Ρ Ο Π Ρ Π Ο Π ΠFractured Carbonate

Impermeable Matrix Ρ Ο Ρ Π Ο Ο Π ΡFractured CarbonatePermeable Matrix Ρ Ο Ρ Π Π Ο Π ΡVugular Carbonate Ρ Ο Ρ Ο Ο Ο Π Ρ

Ρ - Probable damagemechanism under most

conditions

Π - Possible damagemechanism under specific

conditions

Ο - Unlikely damagemechanism under majority

of conditions

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Reservoir Effects and Flow Potential

Overbalanced Rate + >50%?

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Skin Damage

k Permeability - md 25h Height - ft 25Pr Reservoir Pressure - psia 2500Pwf Flowing Well Pressure - psia 1200u Viscosity - cp .95r e Drainage Radius - ft 1500r w Wellbore Radius - ft .26

B Formation Volume Factor 1.5

UBD OBD OBD

S Skin Factor 0 +5 +1

Q STB/Day 510 312 22$/day Incremental Loss @ $25/BO 0 -$4,950 -$7,12

Skin

Formation Damage

Skin

Formation Damage

7.08 X 10-3 kh (Pr -Pwf )uB (ln r e /r w - 0.75 + S)

q =

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Effect of Skin Damage on Production Rates

0

200

400

600

800

1,000

BOPD

5 10-2 0 15-3 -1

Flow Efficiency = 8/(8+S)

SKIN (S)

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••

•

Skin Damage Effect on Productivity & CashFlow

• Difference between Skin of 0 & 30 = $150mm!!!!

• Typically Conventionally drilled wells are in the +/-10 range at best,this still equates to +/- $100mm left in the ground.

• Can we afford to leave this much value behind?

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The Key Underbalanced Benefit - Adding Value to the Well

2 4,900 $220 mm $20 mmUBS Well

BBL /Day

6,500

3,100

1,900

LostValue

--

$90 mm

$150 mm

SKINFACTOR

0

10

30

TypicalRangefor Over-BalancedWells

NPV

$240 mm

$150 mm

$90 mm

Based on a North Sea well -

Oil Price $18 / BBL, Lifting Cost $1/BBL

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Ultimate Recovery Factor

Overbalanced Value + >20%?

Increase Rf (Recovery factor)?

Porosity cut off and impact on reserves

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Increase Rate and Economics

Time >>>

Q , R a t e ( B O P D o r M C F / D ) > >

>

Simplified Reservoir Recovery

Maximum Rate - Reservoir Damage

Damaged Reservoir,

S = >0

Maximum Rate - NO Reservoir Damage

Undamaged Reservoir,S = <0

Incremental Rate

Incremental Time/OpEX

{

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If the results or potential are thisgood why isn’t the industry readily

embracing the technology now ?

THE DECISION MAKER

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THE DECISION MAKER - ENABLER/BLOCKER PYRAMID

Blockers / IssuesDecision MakersEnablers / Drivers

$$$s Public Benefit

NPV Energy Security↑ ProductionShare PriceReduced CostsAffordable Energy

↑ ProductivityPotential ↑ Rf

Access to Depleted Reservoirs↑ Field Life

↓ Lifting Costs

↑ ProductionFaster Drilling

Enhanced Performance

Reduced Costs

OPERATIONS

PRODUCTION MANAGERS, PRODUCTION ENGINEERS

DRILLING MANAGERS, DRILLING ENGINEERS ETC

RESERVOIR ENGINEERS

PRODUCTION TECHNOLOGISTSCOMPLETION ENGINEERS

GEOLOGISTS AND GEOPHYSICISTS

CEOsOWNERS

INVESTORSASSET MANAGERS

GOVERNMENT/AGENCIES

Cost Appreciation of Value

Safety, ↑ RiskLack of AwarenessDamage to CareersHigh Age of Decision Makers, TooClose to Retirement - No Changes

↓ Belief, No Time for New IdeasDifficult to Model ResultsCreates Attitude of ‘We can’t…’Difficult to Predict Productivity

Challenge to Basic FundamentalsSafety, Costs, EducationTraining,↑Complex, RiskLittle or no Steer FromAbove, Buried in Work,

No Time for New Design

E di th UBD M k t

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Expanding the UBD Market

Economic withconventionaltechniques

Knownhydrocarbonresources Economic with

Hydraulic Fracturing

ExpandedUBD

Market

KnownUBDPlays

More risk Less risk

Performance of Shell

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North Sea Field Horizontal Wells(overbalanced )

0

1000

2000

3000

4000

5000

A B C D E F G H I J K L M

Well Name

O

i l P r o d u c t i o n

b / d

Forecast

Ac tual

• Actual results 14% higher than initial forecasts

• Only 8 out of 13 producerswith actual results within±50% of the forecasts

• Random nature of theerrors:

– well F expected to be5th best of 13, is the

worst producer

– well J expected to rank11th of 13, is the bestproducer

Ref: SPE 30745, D. Beliveau, Heterogeneity, Geostatistics, Horizontal

Wells, and Blackjack Poker,

1995 SPE Annual Technical Conference and Exhibition,

Dallas. Oct 22-25

Performance of early Weyburn

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Performance of early WeyburnHorizontal wells

0

100

200

300

400

500

600

1 1 H z

- 0 2

0 1 H z

- 1 4

1 2 H z

- 1 1

0 3 H z

- 1 3

1 5 H z

- 2 1

0 9 H z

- 0 7

1 1 H z

- 1 0

0 3 H z

- 1 0

1 3 H z

- 1 1

0 5 H z

- 0 7

1 1 H z

- 0 1

0 7 H z

- 1 2

0 1 H z

- 2 3

0 9 H z

- 1 4

0 7 H z

- 2 4

A v e r a g

e

Well Name

O

i l P

r o d u c t i o n b

/ d

Forecast

Actual

• 100% “accuracy” over thetotal program : coincidenceand hazard

• Average error of 47% on anindividual Weyburn H-well

• Only 16 out of 29 producerswith actual results within±50% of the forecasts

Ref: SPE 30745, D. Beliveau, Heterogeneity, Geostatistics, Horizontal

Wells, and Blackjack Poker,

1995 SPE Annual Technical Conference and Exhibition,

Dallas. Oct 22-25

Many fields or plays exhibit a

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y p ylog-normal distribution of well productivity

F r e q u e

n c y

( n u m b e r o f w e l l s )

Field average (“mean”)

Most likely (“mode”)

Well production rateÆ

Non-productive

wellsProductive wells

“The laws of well productivity”

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The laws of well productivity

F r e q u e

n c y

( n u m b e r o f w e l l s )

Field average(“mean”)

Most likely (“mode”)

Well production rateÆ

Non-productive

wells

Marginal or

sub-economic wellsThe 20% to 30% of wells that make the field economic

1. 20% to 30% of wells will

make the field economic

2. The chances of the first well

being “above average” is 1/3or less.

3. Statistically, any single well

has a 60+% chance of being

below average or non-productive

4. You need 5+ wells to achieve

the average.

Implications for Underbalance of

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Implications for Underbalance of “The laws of well productivity”

• A good first well does not prove the viability of the play;conversely, a bad first well does not condemn it.

• On average, it takes several wells to prove/disprove a concept.

• Underbalance Industry’s challenge is to – Participate in projects that will prove/disprove the concept

with the least expenditure and lowest risk

– Help operators create a well-thought out plan to get the bestresults from the least expenditure

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Basic Operational Aspects and Systems

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G I j ti M th d

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Gas Injection Methods

Drillpipe Parasite String Concentric String

Degrees of Complexity - Underbalanced Operations

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HIGHMIDLOW

Operations

Compression Air

Nitrogen Membrane

Foam / Chemicals

4 Phase Separation /Data Acquisition

EquipmentRotating Control Heads

Deployment ValveWL Retrievable Float

PersonnelWellsite Supervision

Corrosion

OTHER

Low Complexity

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p y

Pr

SH

Yellow - Monitoring

Red - Safety Shut-Down

BOOSTER

COMPRESSION

High Complexity

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RCD

UBDCHOKE

MANIFOLD

WATER & OILMEASUREMENT

DRILL CUTTINGS DISPOSAL

RETURN MUD to PITS

DRILL CUTTINGS PROCESSING

GASMEASUREMENT

Yellow - Monitoring

Red - Safety Shut-Down

LIQUID NITROGEN

BOOSTERS

NITROGENMEMBRANES

4 PHASE

SEPARTOR

OIL / WATERPROCESSING

FACILITIES

COMPRESSORS

Rotating Control Heads

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Rotating Control Heads

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Compressible Fluids

Dynamic Area of New Research

Base Fluids Selection (Medley et al., 1995)

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ROTATING DIVERTER

SEPARATION

SOLID/LIQUID/GAS

COMPRESSOR / N2

COST

CORROSION

VIBRATIONS

HYDRAULIC CALCULATIONS

CUTTINGS LIFTING

FLUID INFLUX

COMPLETION

BOREHOLESTABILITY MWD TRANSMISSION

HIGH TORQUE/DRAG

UNDERBALANCEDFIRE/

EXPLOSIONS

Range of Available Drilling Fluids

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Range of Available Drilling Fluids

Compressible Fluids Technology

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Compressible Fluids Technology

• UBS Fluid Types:

– Recyclable FoamSystems

– Non-emulsifyingFoaming Agents

– CorrosionChemicals

– PotassiumFormate Drillingand CompletionFluids

– Non-aqueousFoams

– Stable 2-φ DrillingMedia99% - 100% 96% - 99% 55% - 99%< 55%

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QHSE - UBS PROCESSES &SYSTEMS

•Industry Organizationsand Regulatory Input

UB Technology Provides Additional Well C l

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Control

• Surface equipment required for UBD can be tested andcapability verified prior to drilling.

• UB wells are generally more thoroughly planned withcontingency plans in place.

• Formation influx is expected, eliminating the element of surprise.

• BOP stacks are tested more thoroughly because they areused more frequently when drilling UB.

• Redundant barrier protection can be achieved with dualstripper models of rotating control heads.

• Primary barrier of well control is not just a fluid column.

IADC

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IADC

• Underbalanced Operations Committee was formed in 1999

• Issues UBD Daily Tour Report to accompany daily rig

report• Defines Risk Levels and Classifications of UBD

• Setting up IADC WellCap™ accredited Well Control

School for underbalanced drilling

IADC UBO Committee Classification System for Underbalanced Wells

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U de ba a ced e s

• Level 0: Performance enhancement only; no hydrocarbon containing zones.

• Level 1: Well capable of natural flow to surface. Well is “inherently stable” and is low level risk

from a well control point of view.

• Level 2: Well capable of natural flow to surface but enabling conventional well kill methods and

limited consequences in case of catastrophic equipment failure.

• Level 3: Geothermal & non-hydrocarbon production. Maximum shut-in pressures less than UBD

equipment operating pressure rating. Catastrophic failure has immediate serious consequences.

• Level 4: Hydrocarbon production. Maximum shut-in pressures less than UBD equipmentoperating pressure rating. Catastrophic failure has immediate serious consequences.

• Level 5: Maximum projected surface pressures exceed UBO operating pressure rating but are

below BOP stack rating. Catastrophic failure has immediate serious consequences.

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Management System Compatibility

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WeatherfordHSE Management

System

HSE

HSG 65

&

NPD

E&P

Forum

• Leadership & Commitment• Policy Strategy & Objectives• Organisation• Hazard & Effects Management• Planning & Procedures• Implementation & Monitoring• Audits

SEPCo• Leadership & Accountability• Risk assessment and management• People, Training and behaviours• Working with contractors• Operations and Maintenance• Management of Change• Customers and products• Community and stakeholder awareness• Crisis & emergency management

• Incidents , analysis and prevention• Assessment, assurance & improvement

Bp

ISO 14001

ISO 9001:2000OHSAS

18001

Engineering Planning

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g g g

• Flow Modeling

• Environmental Impact

• Conceptual Well Design

• Conceptual Basis of Design for Surface Equipment

• Conceptual Basis of Design for Sub Surface Equipment• Well Control / Barrier Philosophy

• Flaring Versus Re - Injection

Documentation

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• Project Execution Plan

• Risk Register

• HAZID• Quality Plan

• Equipment Integrity Assurance Scheme

• Detailed Well Program

• Manufacturing Schedule

• Certificates of Approval of Equipment

• Manuals / Procedures / Process

• Operations HAZOP

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Brief Summary of a comparativecase study of successful underbalanced drilling operations

Location - Western Lithuania,Operator - Minijos Nafta

Underbalanced Drilling SuccessUnderbalanced Drilling Success

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gg

• Onshore Multiple Well Project

• Gargzdai License

• Western Lithuania

• Cambrian Sandstone Reservoir

Underbalanced Drilling Operations

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Garg11 -1981.70

Garg12 -1939.10

Garg13 -2083.40

Garg14 -1964.40

Garg16 -1997.10

Garg17 -1983.60

Garg18 -1937.29

Garg4 -1991.70

Garg6 -1938.10

Garg7 -1940.83

-1938.53

-1933.53

-1937.50

PS1

-1929.70

PS2

PS3

PS4

6160000 6160000

6161000 6161000

6162000 6162000

6163000 6163000

6164000 6164000

6165000 6165000

6166000 6166000

4

5 2 6 0 0 0

4 5 2 6 0 0 0

4

5 2 7 0 0 0

4 5 2 7 0 0 0

4

5 2 8 0 0 0

4 5 2 8 0 0 0

4

5 2 9 0 0 0

4 5 2 9 0 0 0

4

5 3 0 0 0 0

4 5 3 0 0 0 0

4

5 3 1 0 0 0

4 5 3 1 0 0 0

Location Map Top Cambrian Structure Map.

Reservoir Details

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• Reservoir Formation: Middle Cambrian Sandstone.

• Reservoir Thickness: 70 -80m

• Ave. Reservoir Depth: 1940-2010m TVD.

• Initial Pressure: 3200 psi

• H2S+CO2: None.• BHT: 191 degF

• Porosity: 1 - 12 %

• Permeability: Over 0.1 mD (Range 0.1-0.5 mD).

• Viscosity: 0.63 cP in situ, 1.44 cP Dead (on surface).

Summary of - Region History

P t i ith d ti ll i thi h

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• Past experience with production wells in this area has

indicated high skin factors and reduced productivity, which hasbeen attributed to near well bore formation damage - using theconventional drilling method.

• Physical invasion of suspended mud solids duringoverbalanced drilling, completion, or kill operations resulting innear well bore plugging.

• The reservoir appears to be relatively sensitive to formation

damage effects associated with conventional overbalanceddrilling operations.

• The highly pressure depleted condition of the formation,combined with high mud weights utilised in the past, resultedin significant overbalanced pressures being exerted in thenear well bore matrix area. This problem will be greatlyexacerbated if conventional drilling practices is to be used infuture planned drilling operations.

• Skin Factor Range: 70-100+

Historical Overbalanced Drilling Problems &Issues

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Issues

Skin

Conclusion:- High skin factors are induced when drilling Overbalanced.

Example : While drilling well PS 1 the skin factor reached a value of 78- Where the first underbalanced well, PS 2 drilled, the skin factor was at avalue of -1.155

Production

While drilling well PS 1 overbalanced the completed well flowed atonly (10m3/day or 63 SBBL/Day)

The first underbalanced well Weatherford UBS drilled in the samefield came up to more than 30 fold that amount per day

(551.3m3/day or 3468 SBBL/Day)

PS2 PS3 PS4 Case Histories

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Underbalanced Completed Wells

PS 2 Case History PS 2 Case History

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• Close offset overbalanced well: G-7 Drilled in 1970’s using Soviet technology100m from PS-2&3 PAD.

• G-7 currently producing 130 bbl/DAY. Maximum initial production was +/- 400bbl/DAY

• PS-2 drilled overbalanced to 7” shoe set just above reservoir section

• Well displaced from water based drilling fluid to dead crude oil from nearby G-7tank battery.

• 6” hole drilled underbalanced into upper reservoir section - not expected to beproducing

• Drilling suspended due to large influx of oil

• Decided to run completions due to testing

while drilling capability of separation package

• Production initially tested to +/- 4000bbl/DAY

-30 fold increase in productivity

• Production declining but still around 2400 bbl/DAY- 18 fold increase over G-7

Productivity Productivity - - OBD Vs UBD WellsOBD Vs UBD Wells

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0

100

200

300

400

500

600

0 50 100 150

Time in Days

P r o d u c t i o n m 3 / d a

y

4000

3000

2000

1000

500

3 UBD Wells

3 OBD WellsPS 2

PS 3

PS 4

S B B L / D a y

Well - ANSENAI Well No : 1 (AS-1)Overbalanced vs. Underbalanced Leg

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g

Overbalanced Leg.

• 1st Leg Drilled Overbalanced through reservoir.

• Low invasion Carbonate based “Blockador” type drilling fluid(Ground carbonate in suspension).

• Drilled through reservoir at +/- 45 deg. Inclination.

• Open hole drill stem test.

• Across entire reservoir section (25m at +/- 45º inclination

• DST Summary “ Suggests start of hydrocarbon producinginterval”.

AS-1 Drill Stem Results - Overbalanced Leg

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• DST ( sequence No T4 - 5 )

– Calculated Liquid Rate : 6.1 - 8.2 m3 / Day

( 38 - 52 BBL / Day ) – Rates calculated from liquid level increase of S.G of 1.18.

– Transmissivity determined to be 3mDm. – Permeability calculated to be 0.1mD ( across 25m zone)

– Simplest model with radial flow assumption used.

– PWF = 16.219 Bar

– PI = 0.0319 m3 / D / Bar

Results of Underbalanced Leg

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• Plugged overbalanced leg with cement plug AS-1 (ST)• Oriented 180º from overbalanced leg Azimuth & sidetracked well

• Drilled horizontally into reservoir section.

• Tracking top reservoir using MWD to steer and flow response -“Production Steering”.

• Produced (1811 BBL) (288 m3)on the 16th April including Bit Trip.

• Well choked back ( 950 PSI on manifold ).

• Production whilst drilling 8 - 10 m3 / hr (51 - 63BBL / HR)

• Production whilst tripping 20-23 m3 / hr (126- 145 BBL/HR)

• Estimated Production - before completion.

Open Flow = 500m3 / Day = 3145 BBL / Day

Lithuania UB OperationsLithuania UB Operations - - ConclusionsConclusions

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• Minijos Nafta increased production on a horizontal UB well by17-30 fold.

• Underbalanced Technology has dramatically improved

productivity in mature reservoirs.

• Operator has more than doubled daily production of 5 fieldswith 4 new wells.

• The UBD technique has proven to be of value in mature tightsandstone reservoirs.

• Underbalanced technology works well in low

porosity/permeability formations.• Efficient management systems have resulted in a safe UBD

operation.

In Summary...

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• Underbalanced Drilling technology can – improve well performance by reducing or eliminating

wellbore damage

– improve rate of penetration – eliminate drilling fluid losses

– eliminate and/or reduce stimulation costs

– provide real-time reservoir analysis & flow test while drilling(potential to generate revenue while drilling)

– greatly reduce environmental impact

– reduce wellbore construction costs

• Leading to improved NPV, IRR, etc. in a safe and efficient

manner with risk managed ALARP

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Conclusions, Questions & Answers

wft ubd dti 020416

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