IPS 14-23 Best Practices for Plug and Perf in Acid ... · Best Practices for Plug and Perf in Acid...

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blicAbdallah Mulhim, Jon Hansen, Saudi Aramco

Zouhir Zaouali, Alan Salsman, Schlumberger

IPS 2014

Best Practices for Plug and Perf in

Acid Fractured Stimulation Wells,

Completed in Tight Gas Carbonate

Reservoir

12 May 2014, 2

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IPS 2014Presenter: Zouhir ZAOUALI

Agenda

• Why Cemented Liner Plug & Perf in TightCarbonate Gas

• Plug & Perf Workflow in Tight Gas Carbonate

• Case Study

• Results and Recommendations

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Why Cemented Liner Plug & Perf?

Current Practice: Open Hole Completion

• Loss of Isolation - Acid Dissolving Rock BehindPacker

• Short Isolation length (<20 ft)• Limited number of Fracs

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Solution: Cemented Liner – Multiple Perf Clusters

• Cement Ensuring Zonal Isolation• Long isolation length (> 80 ft between

stages)• Fracturing all stages

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0

500

1,000

1,500

2,000

2,500

3,000

3,500

0 500 1000 1500 2000

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Mscf

Time, days

For all permeabilities cumulative production is

decreasing in the following order:

1. Cased Hole, Plug & Perf, 16 fractures

2. Open Hole, MSF completion, 4 fractures

3. Cased Hole, Plug & Perf, 4 fractures

4. Open Hole, No stimulation

But the difference between them is decreasing

with increasing of permeability

+26%k = 0.01 mD

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

0 500 1000 1500 2000

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Time, days

+14%k = 0.1 mD

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

0 500 1000 1500 2000

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Time, days

Only +2%k = 1 mD

OH_no fracs OH MSF_4 fracs

Cased Hole_4 fracs P&P_4stgs x 4 fracs


Production Simulation

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Cemented Liner Plug & Perf Completion

Workflow

Perforate Stage 1 on Tractor/CT

Injectivity Test

Pc, Pr, Frac Gradient, transmissibility

…

Acid Frac

Perforate Stages 2 with Pump Down

Tractor as a contingency (non injectivity)

Milling Plugs with CT

Multi-finger Caliper/Cement Bond Log

Assess the production casing

Stages & Clusters Selection

OH logs, Caliper, Geomechanic, CBL, well trajectory,

completion, ….

Flow Test

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Well A: Clusters/Stages Selection

St 1St 2St 3St 4St 5

PermCementQualityLithoCaliper

Target high perm zones

Avoid tight dolomite strikes

Sonic & Geomechanic datahave to be considered.

Washout may cause poorcement quality (Caliper)

Keep at least 2 collarsbetween 2 stages

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Well A: Perforation System & Conveyance


Tractor

HSD Guns(3 x 2ft)

Reduced Operating Time compared to CT.

Accurate and more efficient depth correlation

Better reach than CT:– Bidirectional and high speed Tractor.

– Large pull and push forces.

Tractor

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Fd

3-4 times faster

Cost Effective (no need forCT/Tractor)

Minimal complexity

Flexibility to adjustperforation clustercompared to CT

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Depth Of Penetration is important to getbeyond the damaged zone.

Perf friction is proportional to EH Diameter ^4. 48% difference in EH (Conv ch1) becomes

369% difference in perf friction compared to169% for Premium charges, where EH differonly by 28%.

SPAN Rock

2 7/8” HSD ConventionalCharges 12 7/8” HSD ConventionalCharges 22 7/8” HSD Premium Charges

Deepest Penetration and optimum EH makes frac jobs more effective bylowering the breakdown pressures, lowering treatment pressures and

improving treatment rates

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Well A: Injection Test & Acid Fracturing

Job

Injection test

Extremely high frac gradient

5 acid frac stages successfully pumped in 5 operating days

Main Job

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Well A: Milling Attempts

Deep, off-center irregular marks on 3 ¼ LIB

Top plug not accessible for recommended 3 ½” mill


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13262-13382ftWell A: Multi-Finger Caliper

Liner Burst/Oval - ratingnot suitable for fracpressures experienced

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Wells A & B: Completion Suitability for High

FG/ Low P res Environment

4 ½”, 13.5 lbf C95 Pipe BodyInternal Yield Pressure

Industry RecommendedMaximum Pressure (4 ½”, 13.5

lbf C95 )

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Results

All stages (5) were completed successfully

Initial Production was 30 MMSCPD and declined with increasingthe choke to 5 MMSCFPD (Fracture close due to High drawdownor short frac length?).

The initial production is higher compared to OH MSF techniques.But this is too early to conclude, due to high reservoirheterogeneity.

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Recommendations for Future JobsPerforating and Formation Breakdown

Use the new engineered Frac Gun (homogeneous EH holes/highpenetration low perf friction)

If formation doesn’t break down and to preserve a planned stage,add more clusters/perforations.

Acid spearhead after perforating stage 1 to lower formationbreakdown pressures

If difficulties rise while pumping the guns (limitation on WHP), bleedof for few hours and add heavier Tungsten weight bars to the gunstring.

Completion

Production Liner upgrade to 4.5”,15.1 lbf, Q125 (higher collapseresist.)

Maintain minimum net pressure (1000-1,500 psi) just above thefracture closure pressure and Limit BHP to safe liner operatingenvelope.

Use flow-through frac plugs instead of full-bore ones

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Recommendations for Future Jobs

Reservoir Evaluation & Geomechanic

Better understand lateral wellbore heterogeneity to optimize thenumber of Clusters/Frac stages by Acquiring:

• Reservoir pore pressure (StethoScope, MDT)

• Natural fractures occurrence (FMI)

• Mineralogy profile (Stingray-ECS)

Determine optimum well placement (Stresses from Sonic Data)

Perform cement evaluation with rig

IPS 14-23 Best Practices for Plug and Perf in Acid ... · Best Practices for Plug and Perf in Acid...

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