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Best Practice forStand-alone Screens

Ian WattieCompletion Engineering Consultant

Yala Peak Limited

Sand Management Forum26th – 27th March 2014

Aberdeen

Stand-alone ScreensBest Practices

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Industry Worst Industry Average Industry Best

Com

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Failu

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Industry Completion Failure DataData for OH Completions with Stand-Alone Screens

Highest Failure Rate for Major Operator: 15 Failures/19 Wells

Average Failure Rate from Industry Database: 39 Failures/110 Wells

Lowest Failure Rate of Major Operators: 4 Failures/71 Wells

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Plugged Screen ()

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Oil rate (bbl/d)

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1. Sand control best practices for selection, design, manufacturing,installation & start-up mostly not followed

2. First wells had no sand control based on log-derived UCS3. Short length screens and large annular gap have much bigger

effect than other bad practices4. Very short screens will plug or erode sooner due to higher

rates/metre5. Very short (e.g. < 10 metres) screen mesh intervals are extremely

sensitive to anything less than ideal practice at every stage6. Screen mesh size too small; very large D10 sand size7. Screens run in brine > 250 NTU picking up debris8. Screens needed to be worked past shale picking up swelling shale9. Lower post-acid loss rate 0.5 bpm - did not clean off all filter cake10. Production declines are fines plugging formation or screen11. Sudden changes in production are wellbore collapse onto screen,

plugging the screen and reducing annulus permeability with re-sorted sand, shale and residual mud-cake

Field Case Causes of ProductionDecline/Disappointment

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Sand Control Best PracticesOutline

• Sand failure risk assessment• Sand control strategy selection• Sand screen selection method• Sand screen manufacturing QA & QC• Completion installation practices• Production start-up

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Sand Control Best Practice

• Sand failure risk assessment - risk of sandproduction– Strength characterisation– Stress characterisation– Formation failure modelling

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Comparison of Log Predicted UCS with Core Measured UCS

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Core Measured UCS, psi

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CS

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Field-1 SamplesField-2 SamplesField-3 SamplesField-4 SamplesUnit Slope Line

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Core Samples Used in UCS Testing

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Formation Strength CharacterizationUse of Core Data to Establish UCS Range

Example Formation Strength CharacterizationCore Measured Unconfined Compressive Strength vs. Depth

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Measured Depth, ft MDRKB

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essi

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th, p

si

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Formation Stress Characterization

Principle Stresses = Vertical, Hz-max, Hz-minAbsolute Stress = Total Stress Acting at DepthNet Stress = Absolute Stress - Pore PressureDepletion Forecast, so Net Stress increases over field

life

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History Matching with Field Data

Comparison of Field Sand Production Data with Model PredictionConventional Wells with Standard, Non-Stress Oriented, Perforations

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Sand Control Best Practice

• Select strategy for sand management– Produce sand to facilities, collect and dispose– Prevent formation failure (wellbore orientation,

fracture and perforation tactics, resin stabilisation,increase pressure, choke back well, shut-in well,redrill well)

– Screen out at sand face (stand-alone screen,gravel pack, frac-pack)

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Sand Control Best Practices• Select and design stand-alone sand control screen

– Select most likely screen type• mesh sizes around D10 from PSD• select maximum od screen size to minimise annulus (max 1”

less than nominal hole size drilled)– Sand screen mesh sizing by proven lab testing methods

• Plugging resistance test flow and return perms (screen & sandpack)

• Sand retention– RDIF selection by testing

• Drillability (inc. shale stability, loss control, rheology)• Completability (inc. formation damage, screen plugging)

– Clean-up treatment by testing• Screen coupon from production line mesh• Sand as per PSD• RDIF with drill solids (including shale)• Clean-up fluid at representative volume

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Formation Sand VariationSample Selection

Particle Size Distribution of Formation Sand Samples

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Grain Diameter (microns)

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High Perm Sand Low Perm Sand Worse Case

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Test Procedures forScreen Qualification

Gradual FormationFailure

• Flow at constant dP• Produced solids conc. and

particle size• Initial / final sand pack,

gravel and screen perms

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Reservoir Drill-In Fluid Selection

Fluid Loss Control

Bridging Agent PSDBridging Agent ConcPolymer/Starch Conc

RheologyPolymer Conc

ReactivityShale stability

Formation Damage

Filtrate / Solids InvasionFiltercake RestrictionDrill Solids Conc / Reactivity

Screen PluggingFiltercake Plugging

Performance Test Criteria

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• Integrated test of:– RDIF (with drill solids inc shales)– Clean-up fluid volume, circulation, pressure

and temperature, soak time– Flowback onto screen

• Screen plugging measurements:– flow initiation pressure– retained flow capacity– peak pressure

Clean-up System Testing

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Screen Plugging Tests

12.2 ppg OBMw/ Super Pickle + Mark II

12.2 ppg OBMw/ 7.5% HCL +25% EGMBE

12.2 ppg NaCL/KCL/NaBrWB DIF w/ EDTA

Filtercake

Formation Sand

12.2 ppg NaBr/KCL WB DIF #3w/ EDTA

Formation Sand

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Integrated System Testing

• Results graph of retained productivityCallanish & Brodgar Screen Plugging Test Results

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12.2 ppgEnviromul OBMSuperPickle +HDC MarkII

Fordacal/MilBarOBM # 2328

SuperPickle +HDC MarkII

KCOOH Fordacal# 2326 WBM

EDTA

Callanish(Halliburton) Brodgar(Baker)

% R

etai

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12.2 ppgEnviromul OBM

7.5% HCL ++25% EGMBE

12.2 ppg NaCL/KCL/NaBr WBM

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Fordacal/MilBarOBM # 23287.5% HCL +25% EGMBE

DIF/Screen/Clean-up Test Results

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WBM # 3w/ EDTA

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Sand Control Best Practices• Procurement

– Qualification testing (for specific screendesign & manufacturing location supplyingproject)• Corrosion testing weave (completion &

production fluids)• Bead testing mesh size• Burst & collapse full size joint• Assess assembly, inspection, repair and quality

control procedures– Manufacturing quality control

• Inspect records for satisfactory performance• Inspect screens for correct assembly and signs

of repair 23

Sand Control Best Practices• Field installation

– Drill reservoir with RDIF MBT < 5ppg (pit, not returns),drilled solids < 50% and < 30ppb

– Avoid too much steering which leaves ledges– Clean boats, rig piping, pumps, shakers and pits– Pickle running string and washpipe– Minimise time between TD and screens on bottom for shale

clock (3-4 days to do all the stiff wiper trip, casing clean-upand RIH practices)

– Circulate open hole to RDIF with zero solids (i.e. same shalestabilisers, same viscosity, same weight to keep holediameter)

– Clean casing to < 0.01% solids in brine returns (not justNTU)

– Make-up all screen using dope-free ideally, or 1” paint brushdoping pin-end only (screen, wash-pipe, work-string)

– Hold acid treatment against sand face to soak filter-cake byholding wellbore static with seals in sealbores 24

Solids Conc in Active System(Initial CaCO3 = 52 ppb; Dilution Rate = 0 bbl/ft)

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DIF Quality Control

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Impact of DIF Quality on Filtercake Cleanup

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Sand Control Best Practices• Production Start-up

– Limit drawdown– Gradual choke opening– Production or reservoir engineer witness

offshore to influence, observe, record andreact

– Repeat for re-starts following first fewproduction trips

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1. Sand control selection practices followed – 2. Sand control design practices followed – 3. Sand control manufacturing quality practices followed – 4. Sand control installation practices followed in procedure, and in

practice – 5. 60 - 80 metre screens will avoid plugging and erosion due to

lower rates/metre – 6. 60 - 80 metre screen mesh intervals are less sensitive than last

wells to anything less than ideal practice at every stage – 7. Annular gap minimised, which has much bigger effect than good

/ bad practices – 8. Screen mesh sized for very large D10 sand size – 9. Run screens in clean brine < 0.01% solids – 10.Avoid plugging screens by keeping shales from swelling – 11.Ensure acid treatment effective by testing, uncontaminated

filter-cake, good placement & exposure time to filter-cake –

Lessons Applied New Field

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Sand Control Best PracticesKey Points Summary

• Core samples for sand strength• Long screens, large OD screens• D10 particle size screen pre-selection & test• Soluble filter cake by lab testing & QC

during drilling & completion operations• Prevent shales swelling (RDIF shale

inhibitors, shale avoidance, exposure time)• Clean pits, pumps, pipes, shakers, brine

and pickle running string & wash-pipe29

Sand Control Best Practices

SPE 73772 An Evaluation for Screen-Only and Gravel-Pack CompletionsSPE 110082 Current State of the Premium Screen Industry: Buyer Beware ….SPE 135294 Comparison of Inflow Performance and Reliability OHGP and OHSAS Completions

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Industry Worst Industry Average Industry Best

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plet

ion

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Industry Completion Failure DataData for OH Completions with Stand-Alone Screens

Highest Failure Rate for Major Operator: 15 Failures/19 Wells

Average Failure Rate from Industry Database: 39 Failures/110 Wells

Lowest Failure Rate of Major Operators: 4 Failures/71 Wells

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