Perforating Design for HTHP Completion: Rigorous Perforating Design for HTHP Completion: Rigorous Testing to Maximize Well ProductivityTesting to Maximize Well Productivity

Alex Procyk, ConocoPhillips, David Atwood, Schlumberger

Presented at the 2012 International Perforating Symposium

Amsterdam

Nov 8-9, 2012

SPE 159920Optimized Cased and Perforated Completion Designs Through The Use of API RP-

19B Laboratory Testing to Maximize Well Productivity

Typical Field CharacteristicsTypical Field Characteristics

Retrograde gas condensateRetrograde gas condensate Initial reservoir pressure ~ 11000-12000 psiInitial reservoir pressure ~ 11000-12000 psi ~ 14,000 ft TVDSS~ 14,000 ft TVDSS 350-375350-375F - F - HNSHNS Sandstone - Relatively high rock strengthSandstone - Relatively high rock strength 20-30 mD Permeability20-30 mD Permeability

Proposed Well Configuration

Cased & Perforated Completion

Why are we looking into the perforating process so Why are we looking into the perforating process so closely?.....closely?.....

…………A real world example from a similar field, with similar A real world example from a similar field, with similar completion design and similar conditionscompletion design and similar conditions

2003 PLT 2008 PLT

Additional Perfs Oct 2005

Initial Perf job:

• Perforated 1000 psi overbalanced in oil based mud

• Poor Well Response from first perfJob Compared to Benchmark well perforated underbalanced

Well 4

Low PLT Response across High Perm zones

Reperf Job:

• 3 years after first perf job

• UB (live well)

• During the perforating operations the shut-in tubing pressure increased from 3,649 to 5,001 psi.

?

2003 PLT 2008 PLT

Additional Perfs Oct 2005

Initial Perf job:

• Perforated 1000 psi overbalanced in oil based mud

• Poor Well Response from first perfJob Compared to Benchmark well perforated underbalanced

Well 4

Low PLT Response across High Perm zones

Reperf Job:

• 3 years after first perf job

• UB (live well)

• During the perforating operations the shut-in tubing pressure increased from 3,649 to 5,001 psi.

?

Perforating Design GoalPerforating Design Goal

Design perfs to achieve desired skin, the Design perfs to achieve desired skin, the first time!first time!

Get full production across entire perforated Get full production across entire perforated zone zone

Perforating RequirementsPerforating Requirements

• Perforation FillPerforation Fill• Crushed Zone PermeabilityCrushed Zone Permeability

Perforation Damage:Perforation Damage:

Perforation Geometry:Perforation Geometry:• Density• Phasing• Diameter• Length

Perforating RequirementsPerforating Requirements

What perforation length do we need?What perforation length do we need?

WHAT PERFORATION LENGTH DO WE NEED? Slide 9

Increasing perforation length provides more skin improvement than increasing shot density

5” Lp: 12 spf/6 spf = 1, 5”/10” = 1.5

Evaluation of Perforation Geometry and Damage EffectsKh=10 md, Kh/Kv=1, H=500 ft TVT, b=Hp/H=1, Incl=0 deg, Kmf/Kr=0.5, rmf=rw+1 ft and rw=0.354 ft for all cases

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Perforation Length, inches

Dar

cy S

kin

SPF=6, Dp=0.25",Phasing=60 deg and Kc/K=0.02 for OB Perforating in High Density Mud

SPF=6, Dp=0.25",Phasing=60 deg and Kc/K=0.12 for OB Perforating in Filtered Brine

SPF=6, Dp=0.25",Phasing=60 deg and Kc/K=0.20 for UB Perforating in Filtered Brine

SPF=6, Dp=0.25",Phasing=60 deg and Kc/K=0.40 for UB Perforating with Best Practices

Target: Best Practices

Beware!Beware!Core Penetration Length Variability

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Test: Rock Penetration Prediction: RockPenetration

Section 1: ConcretePenetration

Co

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en

etr

ati

on

Le

ng

th (

in.)

2-7/8" gun, 4500 psi UCS rock strength, 7150 psi apparent effective stress

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Perforating RequirementsPerforating Requirements

How should we perforate?How should we perforate?

• OverbalancedOverbalanced

• UnderbalancedUnderbalanced

• In Mud?In Mud?

• In Brine?In Brine?

What perforation conditions do we need?What perforation conditions do we need?

Perforating Damage—PerformancePerforating Damage—Performance

Sand debris

Reduced permeability crushed zone, Kc

Damaged zone, Kd Undamaged formation, KDmg depth

Penetration, P

Sand debris

Reduced permeability crushed zone, Kc

Damaged zone, Kd Undamaged formation, KDmg depthDmg depth

Penetration, P

S a n d d e b r i s

D a m a g e d z o n e , K d U n d a m a g e d f o r m a t i o n , KD m g d e p t h

P e n e t r a t i o n , P

S a n d d e b r i s

D a m a g e d z o n e , K d U n d a m a g e d f o r m a t i o n , KD m g d e p t hD m g d e p t h

P e n e t r a t i o n , P

Damaged zone, Kd Undamaged formation, KDmg depth

Penetration, P

Damaged zone, Kd Undamaged formation, KDmg depthDmg depth

Penetration, P

Poor skin

Good skin

Fair skin

Perforation Design: Competing InterestsPerforation Design: Competing Interests

Best Practice for CompletionsBest Practice for Completions Perforate Underbalanced in filtered brinePerforate Underbalanced in filtered brine Run as large guns as possible – 3.5”Run as large guns as possible – 3.5”

Can the Two Competing Interests meet?Can the Two Competing Interests meet?

Best Practice for Operations Perforate overbalanced in mudPerforate overbalanced in mudRun 2-7/8” gunRun 2-7/8” gun

Test all ScenariosTest all Scenarios

UnderbalancedUnderbalanced Static underbalance: Static underbalance: 1500 psi1500 psi Dynamic underbalance: Dynamic underbalance: 3500 psi3500 psi

OverbalancedOverbalanced 500 psi500 psi

In mud (per fluid)In mud (per fluid) In base oilIn base oil 3-1/8” gun3-1/8” gun

1. Flow Tests (skin):

2. Penetration Tests (length)2-7/8” gun2-7/8” gun3-1/8” gun3-1/8” gun

1. Flow Test1. Flow Test “Section 4”

Crushed Zone Permeability MeasurementCrushed Zone Permeability Measurement

Section 4 test not rated for actual conditions

Confinement: 5800 psia (13000 psia)

Pore Pressure: 4500 psia (11700 psia)

Wellbore Pressure: 3000-5000 psia

Temperature: 200F (350F)

Core Fluid: Mineral Spirits (condensate)

Test Scenarios

Scenario A: Shoot overbalanced with mud, no DUB, kill

Scenario B: Shoot overbalanced with mud, 3500 psi DUB, kill

Scenario C: Shoot 1500 psi underbalanced in base oil, no DUB

Scenario D: Shoot balanced in base oil, 3500 psi DUB

Number of Type of Fluid Static Wellbore Pressure Dynamic Underbalance Post-PerforationPerforation Tests In Wellbore Prior to Perforating Applied During Test Well Kill Performed

2 Tests 16.5 ppg OBM 500 psi Overbalance 3500 psi Dynamic Underbalance Kill with OBM/Hold for 72 hrs2 Tests 7.0 ppg Base Oil 50 psi Underbalance 3500 psi Dynamic Underbalance Kill with Base Oil/No Hold1 Test 7.0 ppg Base Oil 1500 psi Underbalance No Dynamic Underbalance Kill with Base Oil/No Hold1 Test 16.5 ppg OBM 500 psi Overbalance No Dynamic Underbalance Kill with OBM/Hold for 72 hrs

no

SECTION 4 TEST PROGRAM RESULTS

SECTION 4 TEST PROGRAM RESULTS

SECTION 4 TEST PROGRAM RESULTS

Slide 21

159920• Optimized Cased and Perforated Completion Designs• Alexander Procyk

Test 3: Base Oil, 1500 psi Static Underbalance, no Dynamic Underbalance, Base Oil kill

Slide 22

159920• Optimized Cased and Perforated Completion Designs• Alexander Procyk

SECTION 4 TEST PROGRAM RESULTS

Test 5: Base Oil, 50 PSI Underbalanced, Dynamic Underbalance, Base Oil kill

SECTION 4 TEST PROGRAM RESULTS Slide 23

CFE Comparison

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70

500 psi SOB, 3500 psiDUB, Mud

50 psi SUB, 3500 psi DUB,Base oil

500 psi SOB, 3500 psiDUB, mud (repeat test 1)

50 psi SUB, 3500 psi DUB,base oil (test 2 repeat)

1500 psi SUB, no DUB,base oil

500 psi OB, no SUB, NoDUB, mud

Test

1Te

st 2

Test

4Te

st 5

Test

3Te

st 6

CFE

No underbalance

1500 psi SUB

3500 psi DUB

FEA Method

SECTION 4 TEST PROGRAM RESULTS Slide 24

Kc/K Summary

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80

500 psi SOB, 3500 psi DUB,Mud

50 psi SUB, 3500 psi DUB,Base oil

500 psi SOB, 3500 psi DUB,mud (repeat test 1)

50 psi SUB, 3500 psi DUB,base oil (test 2 repeat)

1500 psi SUB, no DUB, baseoil

500 psi OB, no SUB, NoDUB, mud

Test

1Te

st 2

Test

4Te

st 5

Test

3Te

st 6

Kc/K

Crush zone thickness = rscrubbed - rjet; djet = 0.15"

3500 psi DUB

no underbalance

1500 psi SUB

Flow ResultsFlow Results Perforating in mud without underbalance Perforating in mud without underbalance

very badvery badno surpriseno surprise

Dynamic underbalance most important Dynamic underbalance most important moderate surprisemoderate surprise

Perforating and killing in mud with Perforating and killing in mud with dynamic underbalance is OKdynamic underbalance is OKSurprise to us!Surprise to us!

Round 1 to OperationsRound 1 to Operations

2. Core Penetration Tests2. Core Penetration Tests

Perform tests at realistic conditionsPerform tests at realistic conditions

Compare against predictionsCompare against predictions

Select deepest penetrating chargeSelect deepest penetrating charge

Confirm Actual Penetration with TestingConfirm Actual Penetration with Testing

PV-40 MOD’D SECTION 2 TEST SYSTEM DESCRIPTION Slide 28

Pore Pressure:

11700 psi

Confinement pressure: 13000 psi

Wellbore pressure:

12000 psi

Temperature:

350 F

Net stress: 1300 psi

Apparent net stress: ~9000 psi

Rock UCS = 7000 psi

Net Stress (psi)

Perf Length – High ExpectationsPerf Length – High Expectations

Expected apparent net stress

Apparent Net Stress = c - Pp

MODIFIED SECTION 2 TEST PROGRAM RESULTS

Perforation Created By 23 g HNS Charge At HPHT Conditions

Slide 30

no

SECTION 4 TEST PROGRAM RESULTS

Apparent net stress = 4400 psi

MODIFIED SECTION 2 TEST PROGRAM RESULTS

Perforation Created By 19 g HNS Charge At HPHT Conditions

Slide 32

Test Core 6B = 4.6 inchTest Core 3T = 5.2 inch

Test Core 7T = 5.81 inchTest Core 2B = 6.75 inch

Test Core 4B = 6.38 inch

Test Core 5T = 6.56 inch

Post Shot - Perf Test Photo’s Post Shot - Perf Test Photo’s

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Solid: PredictedShaded: Actual

Core Penetration: Predicted vs. Actual

Company

2-7/8" gun, 4500 psi UCS rock strength, 7150 psi apparent net stress

REVISED RESULTS USING SECTION 2 AND 4 RESULTS Slide 35

Skin Evaluation Incorporating Section-2 and Section-4 Test Results

Kh=10 md, Kh/Kv=10, H=500 ft TVT, b=Hp/H=1, Incl=0 deg, rmf=rw+1 ft and rw=0.354 ft for all cases

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Perforation Length, inches

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kin:

Sto

tal=

S+D

*Q w

ith Q

=100

MM

SC

FD

. Initial Screening Case: SPF=6, Dp=0.25",Phasing=60 deg and Kc/K=0.4 for UB Perforating with Kmf=0.50

Modified Screening Case: SPF=6, Dp=0.25",Phasing=60 deg and Kc/K=0.4 for UB Best Practices with Kmf=0.75

Design Case with Section-2 and Section-4 Results: SPF=6, Dp=0.85",Phasing=60 deg and Kc/K=0.4 for DUB with Kmf=0.75

Best Laboratory Test Case: SPF=6, Dp=0.85",Phasing=60 deg and Kc/K=0.7 for DUB with Kmf=0.75

Initial Skin = +1.9 with

Lp=12" and Dp=0.25"

Final Skin = +1.0 with Lp=6.75" and Dp=0.85"

Expected skin @ 12” penetration, 0.25” diameter

Perf Geometry much different than expected, but yields roughly the same skin due to huge diameter (= flow area)

Some things to think aboutSome things to think about

• Perforation characteristics : - “Carrot Shape” Perforation characteristics : - “Carrot Shape” (Short & Dumpy) – (Short & Dumpy) –

• Is this an HNS artifact?Is this an HNS artifact?

• What effect does the saturating fluid play?What effect does the saturating fluid play?

• Is the carrot shape indicative to the lower rock Is the carrot shape indicative to the lower rock strength only. What happens in higher rock strength?strength only. What happens in higher rock strength?

Is Short and Fat still acceptable with a low perm mud filtrate invaded zone?

Pushing Testing FurtherPushing Testing Further

• How do we encourage the industry to cut larger ID How do we encourage the industry to cut larger ID core in actual HPHT rock to advance testing core in actual HPHT rock to advance testing further……..(UK & Norway) are the main user of this further……..(UK & Norway) are the main user of this HPHT perf technology..HPHT perf technology..

• How do we improve analogue rock selection, is How do we improve analogue rock selection, is synthetic rock a option? where are we with this synthetic rock a option? where are we with this technology? technology?

• Testing in Brine. Tests resulted in vastly improved Testing in Brine. Tests resulted in vastly improved penetration. "Reality" future testing requires penetration. "Reality" future testing requires accurate saturation of the core to demonstrate if accurate saturation of the core to demonstrate if improvement associated with rock saturation.improvement associated with rock saturation.

• Gun design for 2 7/8" HPHT Guns (Central Gun design for 2 7/8" HPHT Guns (Central Grabben Type Formation use 2 7/8“ due to 5” Grabben Type Formation use 2 7/8“ due to 5” Tubing /Liners ) has Tubing /Liners ) has probablyprobably reached its limit. reached its limit. There has to be quantum leap in technology to There has to be quantum leap in technology to make any difference and this does not seem to make any difference and this does not seem to be available today. be available today.

• DUB: Cannot actually measure the event in DUB: Cannot actually measure the event in real time due to limitations of gauge real time due to limitations of gauge technology (temp) both in the lab and in the technology (temp) both in the lab and in the field. field.

Pushing Equipment FurtherPushing Equipment Further

Acknowledgements / Thank You / Questions

Paper # • Paper Title • Presenter Name

The authors wish to thank the management of both ConocoPhillips Company and Schlumberger for permission to publish this work. The authors also wish to thank the PERF Lab engineers and technicians involved in this work for their diligence in performing these tests to ensure meaningful and consistent test results.

Slide 39

Perf Length Test ResultsPerf Length Test Results

Charges shot shorter than expected in HPHT Charges shot shorter than expected in HPHT TestsTests

Charges had larger perforation diameters in Charges had larger perforation diameters in HPHT TestsHPHT Tests

3-1/8” did not shoot significantly deeper than3-1/8” did not shoot significantly deeper than

2-7/8”, at least settling that argument2-7/8”, at least settling that argument

Perf Length Test ResultsPerf Length Test Results

Charges shot shorter than expected in HPHT TestsCharges shot shorter than expected in HPHT Tests

Charges had larger perforation diameters in HPHT TestsCharges had larger perforation diameters in HPHT Tests

Perf Geometry depended upon saturating fluid (OMS vs Perf Geometry depended upon saturating fluid (OMS vs brine)brine)

3-1/8” did not shoot significantly deeper than3-1/8” did not shoot significantly deeper than 2-7/8”, at least settling that argument2-7/8”, at least settling that argument

DUB and perf geometry should be sufficient for our skin DUB and perf geometry should be sufficient for our skin goals (stay tuned)goals (stay tuned)

4” perf length

8” perf length

14” perf length

Length vs Total Skin

Well 3

Additional Perfs Oct

2006

2003 PLT

Low PLT Response across High Perm zones

Initial Perf job:

• Perforated overbalanced in oil based mud

• Poor Well Response from first perf Job Compared to Benchmark well perforated underbalanced

Reperf Job:

• 3 years after first perf job

• UB (live well)

J03 Backpressure Plot

1.0E+05

1.0E+06

1.0E+07

1.0E+08

1 10 100

Rate (mmscf/d)

P*^

2 -

Pw

f^2

(psi

a^2

)

2002-2004

2005-2006

2007-2009

2010

Data in IPR Graph

Production Model, S = 12.5

Well 3 Backpressure PlotWell 3 Backpressure Plot

Original Completion

After Reperf