sand control

Sand Control

Copyright 2007,

, All rights reserved

Completions Type

Barefoot (Openhole) Slotted LinerCemented Casing/liner

Fracpack

Completion Type

Screen/ open hole

External GravelpackChemical Consolidation

Internal Gravelpack

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SAND PRODUCTION PROBLEMS AND PRODUCTIVITY EFFECTS

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Sandstone Reservoirmineral grainQuartz, SiO2

natural cementingCaCO3

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SAND PRODUCTION CONTROL AND PRODUCTIVITY EFFECTS

SAND PRODUCTION MECHANISM

As fluids flow through a porous material, drag forces are created along the path of flow. Depending on the degree of natural intergranular cementation, compaction, intergranular friction, and cohesion of particles making up the porous material, flowing fluid may carry with it considerable quantities of loose and friable sand grains.

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Sand Production

Once the destabilizing forces overcome the formation strength, the rock will fail.Sand production will follow if sand can be transported.

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Sand and Fines

Fines solids with 44 microns Fines are most probably produced in every well.

Fines are not controlled. They can be dissolved.Sand can not be dissolved. Needs to be controlled.

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SAND PRODUCTION CONTROL AND PRODUCTIVITY EFFECTS

PRODUCTIVITY EFFECTS

Erosion damage of surface and subsurface production equipment (eg.Casing/liner failures) Plugging of well and surface production facilities

Sand Disposal

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SAND PRODUCTION CONTROL AND PRODUCTIVITY EFFECTSSand production during a four-rate testSAND RATE CRITICAL OIL RATE

OIL

OIL RATE

SAND

TOLERABLE FINES

0Copyright 2007, , All rights reserved

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PRODUCTION TIME, MONTHS

FACTORS INCREASING SAND PRODUCTION

Decline of reservoir presssure (increase of overburden pressure) Cementing Material, Degree of Consolidation Fluid Viscosity, Production Velocity, Drag Forces Increasing water production (destroys intergranular cementing material) Formation damage (increases drawdown)Copyright 2007, , All rights reserved

Causes of Sand Production (I)

Time Dependence decreasing reservoir pressure increases the effective stress on the grains (overburden is constant)

Fluid Flow fluid velocity and viscosity contributes to the pressure drop near the wellbore (drag force) production induces stress on the formation sand induced stress > formation stress sand production

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Causes of Sand Production (II)

Geological Factors tertiary age reservoirs, usually shallow depths unconsolidated

Impairment on Natural Consolidation high compressive strength internal pore pressure supports the overburden

' - PCopyright 2007, , All rights reserved

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Causes of Sand Production (III)Mutiphase Flow

Water production may dissolve natural cementing materials weakening the intergranular bonds; Water production may mobilize fines resulting in plugging of the pore structure.

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Prediction of Sand Production

Experience Analogy Special Well Test Core Inspection and Testing

Measurements Log Interpretation Correlations

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MEASURES TO CONTROL SAND PRODUCTION

1. 2.

Reduce producing oil and gas rates below the critical rate for sand production. Prevent sand production mechanically by screen or gravel pack.

3.4.

Chemically consolidate the formation sand near the wellbore using resinous material.Inject resin-coated gravel into the perforations to pack and stabilize the perforations.

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MEASURES TO CONTROL SAND PRODUCTIONCONTROLLING PRODUCTION RATES

PrINFLOW BOTTOM HOLE FLOWING PRESSURE, Pwf

OUTFLOW (CONTROLLED)

CRITICAL DRAW-DOWN

CRITICAL SAND FREE OIL RATE0 0FLOW RATE, Q

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Methods for Sand Control

Screnless

With Screen

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Screenless Methods for Sand ControlIn-situ consolidation

Use of resins to consolidate formations.

Resin-Coated Gravel

Injection of pre-coated gravel., All rights reserved

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Methods for Sand Control using Screen

Gravel Pack Natural Sand Pack (NSP)

Frac & Pack (Frac-n-Pack, Frac-Pack, StimPAC*)

* - mark of SchlumbergerCopyright 2007, , All rights reserved

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MEASURES TO CONTROL SAND PRODUCTION (GRAVEL PACK)MECHANISMS OF MECHANICAL RETENTIONBRIDGING FILTER-SIZE RETENTION

SANDGRAVEL GRAVEL

SAND

THE WHOLE IDEA BEHIND GRAVEL PACKING IS THAT THE GRAVEL MAY BE SIZED TO EFFECTIVELY RETAIN THE FORMATION SAND AND THE SCREEN MAY BE SIZED TO RETAIN THE GRAVEL

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MEASURES TO CONTROL SAND PRODUCTIONMECHANICAL SAND RETENTION INSIDE CASING GRAVEL PACK UNDERREAMED CASING GRAVEL PACK SCREEN LINER IN OPEN HOLE OPEN HOLE GRAVEL PACK UNDERREAMED OPEN HOLE GRAVEL PACK

Copyright 2007,


PERMEABILITY REDUCTION AS A FUNCTION OF RATIO OF GRAVEL SIZE TO FORMATION GRAIN SIZE (After Saucier)

1.0RULE OF THUMB

0.8 K/Ki 0.6 0.4 0.2 0 0 2 4

dG50(optimum) = 5 or 6dR50

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dG50/dR50Copyright 2007, , All rights reserved

Gravel PackSand - Gravel - Screen

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FORMATION GRAIN SIZE STATISTICAL DISTRIBUTION (Sieve Analysis)

RETAINED WEIGHT, PERCENTAGE

40

3020

100 0.010.001 0.0001

PARTICLE SIZE, INCHESCopyright 2007, , All rights reserved

FORMATION GRAIN SIZE DISTRIBUTION (Sieve Analysis Results)100 90 80 70 60 50 40 30 20 10 0 1.0

CUMULATIVE PERCENTAGE BY WEIGHT

DG50(optimum) = 5DR50

DR50 0.1 0.01 0.001 0.0001

GRAIN DIAMETER, INCHESCopyright 2007, , All rights reserved

OPTIMUM GRAVEL SIZE DIAMETER AND OPTIMUM SCREEN SIZE

(*) 100 90 80 70 60 50 40 30 20 10 0 1.0 (*)CUMULATIVE PERCENTAGE BY WEIGHT

DG50(optimum) = 5DR50

DLINER SLOT = 0.5DGmin

COMMERCIAL GRAVEL RESERVOIR

DGminDR50 DG50

0.1

0.01

0.001

0.0001

Copyright 2007,


FOR SCREEN LINER IN OPEN HOLE DLINER SLOT = 2xDR10 FOR NONUNIFORM SAND AND = DR10 FOR UNIFORM SAND

GRAIN DIAMETER, INCHES

MEASURES TO ACHIEVE PROPER INSIDE CASING GRAVEL PACK

1. PROPERLY SIZED GRAVEL AND SCREEN LINER.2. SHOOTING LARGE DIAMETER PERFORATIONS TO ALLOW EFFECTIVE PLACEMENT OF GRAVEL.

3. CLEANING AND WASHING THE PERFORATIONS TO REMOVE DEBRIS FROM THE PERFORATIONS.4. EFFECTIVE TRANSPORT AND PLACEMENT OF THE GRAVEL IN THE PERFORATIONS. 5. PRESSURIZING AND SQUEEZING GRAVEL IN THE PERFORATIONS. 6. MAINTAINING CLEAN WELLBORE FLUIDS THROUGHOUT THE GRAVEL PACKING OPERATION.Copyright 2007, , All rights reserved

COMMERCIAL GRAVEL DATA____________________________________________________________________________________________________ Aprox. G=bkG-a Sand/Gravel US Mesh Median Porosity Permeability ________________________ Size(in.) Size Dia.(in.) (%) (mD) a b ____________________________________________________________________________________________________ 0.006 ----- 0.017 40/100 0.012 0.008 0.017 40/70 0.013 0.010 0.017 40/60 0.014 32-39 1.2x105-1.7x105 1.6 2.12x1012 0.017 0.033 20/40 0.025 35-40 1.54 2.12x1012 0.023 0.047 16/30 0.035 0.033 0.066 12/20 0.050 0.039 0.066 12/18 0.053 0.043 0.079 10/20 0.056 32-40 5x105-6.5x105 1.34 8.4x1011 0.047 0.079 10/16 0.063 35-40 17x105-20x105 0.066 0.094 8/12 0.080 36-40 17x1051.24 5.31x1011 0.079 0.132 6/16 0.106 -42 ____________________________________________________________________________________________________

By convention, 20-40 mesh commercial gravel passes through a 20 mesh sieve and is retained by a 40 mesh sieve

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PROCEDURES TO COLLECT SAMPLES OF FORMATION SAND

1. RUBBER-SLEEVES CORES 2. CONVENTIONAL CORES 3. SIDEWALL CORES 4. PRODUCED SAND FROM THE SEPARATOR OR SAND TRAPNot recommended

5. SAND BAILERS

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Sampling

per layer critical for gravel size determination

full core samples are best bail samples are not representative because of loss of high and low ends of particle distribution

sidewall cores are acceptable frequent sampling heterogeneous formation - 1 ft uniform formations - 5, 10, 20 ft spacing

shale-shaker representative, if collection is accurate

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Sample collection

size

% cumulative

%

size (log)

bail sample (high end) core sample bail sample (low end)

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GRAVEL PACK PLACEMENT

(Washpipe raised)

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GRAVEL PACK EVALUATION

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EXERCISEWell X4 is to be gravel packed. A sidewall sample was available and a sieve analysis was made. Results of the analysis are shown in the following table:_________________________________________________________________ U.S.sieve Grain Weight Cumulative Number diameter retained Weight weight (mesh) (in.) (gm) percent percent _________________________________________________________________ 8 0.0930 12 0.0661 16 0.0469 20 0.0331 30 0.0232 0.25 1.4 1.4 40 0.0165 50 0.0117 0.79 4.3 5.7 100 0.0059 2.81 15.4 21.1 140 0.0041 3.25 17.8 38.9 200 0.0029 4.10 22.5 61.4 270 0.0021 325 0.0017 4.52 24.8 86.2 Pan 2.52 13.8 100.0 Totals 18.24 _________________________________________________________________

solutionCopyright 2007,

Suggest gravel and screen for gravel pack design for the well., All rights reserved

First Selections

1st: select fluid system least damaging, economical, efficient

2nd: select gravel and screen or slotted liner size and type

3rd: NODAL analysis: evaluate effect on well productivity

4th: Re-select fluids and gravel if necessary

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Gravel Pack PreparationAlways

In OH, clean mud cake prior running screen

In CH, ensure that all perforations are open and cleanClean tubing prior to any pumping

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Internal gravel packCased Hole ConsiderationsReliable drilling and completion methodologies Requires efficient perforation system Isolate production from undesirable zones

Poor perforation pack may lead to low productivity

Easier workover compared to EGP

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External gravel packOpen Hole ConsiderationsCan be Underreamed, increasing wellbore area No damage due to poor perforation pack efficiency

Hole stability is a concern while drilling and completion

Water production control may become impractical

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Circulation system - IGP

Fluid may leak to the formation, may be circulate back to the surface or both.

When pumping slurry, gravel will be placed inside perforation tunnels and annular casingscreen.

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Circulation system - EGP

Fluid may leak to the formation, may be circulate back to the surface or both.

When pumping slurry, gravel will be placed in the annular formation-screen.Accessories : Lower and Upper Telltale.

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Squeeze system - IGP

Fluid may leak only to the formation. Fluid may travel through inside the screen. When pumping slurry, gravel will be placed inside perforation tunnels and annular casingscreen.

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Formation Analysis

Lithology, definition of fluids Granulometry, selection of gravel size

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Fluids Compatibility

potential damage by fines migration (clays) formation cores are often unavailable

inference from lab studies on similar formationsrequires comprehensive clays analysis of the samples

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Clay Chemistry

Montmorillonite swelling clays sensitive to fluids with low NaCl content

Kaolinite, illite and chlorite dispersed by fluid movement NaCl increases the sensitivity of the clays CaCl2 is normally used instead of NaCl

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Clays

In Gravel Packing, potential clay problems merits serious consideration when clay content equals or exceeds 5%. As a prevention, a clay stabilizer should be add to the carrier fluid.

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Acid clean-up prior to gravel pack

HCl dissolves calcium scale and improves injectivity Fluoboric Acid - controls swelling and movement of clays and fines (dissolves most and stabilizes the remain) Maximum operational flexibility Increased leak-off rate during GP

Do not overflow the well after treatment

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Filtration

All fluids must be filtered preferably at well site; avoid contamination in tanks and transports

Brines must be filtered at 2 Gels must be filtered at 10 15/64 in to 3/8 in choke at 500 psi estimate 10% reduction in viscosity

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Damage caused by solids

500 A (2.5 ppm) (A) Bay Water Filtered Through 2um Cotton Filer (B) Bay Water Through 5um Cotton Filter (C) Produced Water Untreated C (94 ppm) D (436 ppm) 10 (D) Bay Water Untreated

Permeability (md)

100B (26 ppm)

50

0

0.02

0.04

0.06

0.08

0.10

Volume Injected (gal/perf)

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Sizing Criteria

Saucier Method: median grain for gravel is 5 or 6 times median grain size for sand formation (D50)g = 5 or 6 x (D50)f Coberly Method: uniform sands. Gravel too large to prevent fines.

Stein Method: uniform sand.Schwartz Method: reduces probability of fines

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Screen, blank pipe & wash pipeScreen length: 5 ft above and 5 ft below perforations minimum gap Screen OD: gap of 1-in per side screen 1-in Wash pipe OD: very close to screen ID Blank pipe OD: slightly less than screen Blank pipe ID: same as screenblank pipe

wash-pipe

screen

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Liners or Screens ?Slotted Linerslow cost robust

Wire Wrapped Screensenhanced control large flow area un-restricted flow

small fluid area pressure loss across slots slots erosion primary control onlyCopyright 2007, , All rights reserved

cost can be high welding might corrode

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The ideal gravel packComplete packing with a properly sized highpermeability gravel. Clear interface between the formation sand and gravel. No invasion of the matrix with damaging material. No reduced-permeability section between the formation sand and the gravel pack. No residuals from the carrier fluid and/or fluidloss pills.Copyright 2007, , All rights reserved

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Poor gravel pack placementPerforation Potential for production loss Open Hole Potential for production loss and/or screen failure (erosion)

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Poor interface Gravel / SandReduced pack permeability Potential for production loss

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Matrix damageInvasion of the matrix by treatment/completion fluids Potential for production loss

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Damage zone

Perforation Crushed Zone Potential for production loss Open Hole Filter Cake Potential for production loss

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Gravel pack damageResiduals from the treatment fluid Potential for production loss

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Multi-zone treatment0 5 10 15 2012840

1

10

1 00

1 000

12840

Pressure (psi)

SP1286012860

ILD

12880

12880

12900

1 2 9 00

10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 0

16

Rate or Conc. (bpm or ppa)

14

Surface Pressure Rate

12 10 8 6 4

Conc.10 20 30 40 50 60

2 0

12920

12920

Time (minutes)

12940

12940

8000 7500

190 180 170 160

Temperature (Deg F)

Pressure (psi)

12960

12960

7000 6500 6000 5500 5000

12980

12980

Temp. Lower Gauge BHP Upper and Lower Temp. Upper Gauge

150 140 130

13000

1 3 000

13020

1 3 02 0

4500 0 10 20 30 40 50 60 Time (minutes)

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Multi-zone treatment

Benefits Interval between zones 6 feet Single trip in hole Single pump stage Simple

Completions Gravel Pack-Frac / Pack 15 jobs to date for PRISA 1 job with 3 zones (2 x MZ)

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Two zones (lower wet)

0 1 0360

50

1 00

1 50

0. 1

1

10

1 00

10360Well Pressure (p si)

6000 5000 4000 3000 2000 1000 0

30Rate (bpm) Co nc (p pa)

1 0380

10380 10400 10420 10440 10460 10480 10500 10520 10540

25 20 15 10 5 0 20 40 Time (min) 60

1 0400

1 0420

1 0440

1 0460

1 0480

1 0500

1 0520

Wet Sand 0

1 0540

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Multi-zones results

Complete Packs of All Zones Significant Completion Cost Savings Elimination of Kill Pills Better Production

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sand control

Documents

inside perforation

sand production

control sand

water production

sand control

sand production

gravel packing

grain diameter