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Copyright 2007, , All rights reserved
Sand Control
Copyright 2007, , All rights reserved
Completions Type
Slotted Liner
Fracpack
ExternalGravelpack
ChemicalConsolidation
InternalGravelpack
Screen/open hole
CementedCasing/liner
Barefoot(Openhole)
CompletionType
Copyright 2007, , All rights reserved
SAND PRODUCTION PROBLEMS AND
PRODUCTIVITY EFFECTS
Copyright 2007, , All rights reserved 4
Sandstone Reservoir
natural cementingCaCO3
mineral grainQuartz, SiO2
Copyright 2007, , All rights reserved
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.
SAND PRODUCTION CONTROL AND PRODUCTIVITY EFFECTS
Copyright 2007, , All rights reserved 6
Sand Production
Once the destabilizing forces overcome the formation strength, the rock will fail.
Sand production will follow if sand can be transported.
Copyright 2007, , All rights reserved 7
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.
Copyright 2007, , All rights reserved
PRODUCTIVITY EFFECTS
• Erosion damage of surface and subsurface production equipment (eg.Casing/liner failures)
• Plugging of well and surface production facilities
• Sand Disposal
SAND PRODUCTION CONTROL AND PRODUCTIVITY EFFECTS
Copyright 2007, , All rights reserved
Sand production during a four-rate test
0 1 2 3 4 5 6 7
PRODUCTION TIME, MONTHS
OIL
RAT
E
CRITICAL OIL RATE
SAND
OIL
“TOLERABLE”FINES
SAND PRODUCTION CONTROL AND PRODUCTIVITY EFFECTS
SAND RATE
Copyright 2007, , All rights reserved
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 11
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
Copyright 2007, , All rights reserved 12
Causes of Sand Production (II)
Geological Factors– tertiary age reservoirs, usually shallow depths
Þunconsolidated Impairment on Natural Consolidation
– high compressive strength– internal pore pressure supports the overburden
P-'
Copyright 2007, , All rights reserved 13
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.
Copyright 2007, , All rights reserved 14
Prediction of Sand Production
ExperienceAnalogySpecial Well TestCore Inspection and Testing
MeasurementsLog InterpretationCorrelations
Copyright 2007, , All rights reserved
MEASURES TO CONTROL SAND PRODUCTION
1. Reduce producing oil and gas rates below the critical rate for sand production.
2. Prevent sand production mechanically by screen or gravel pack.
3. Chemically consolidate the formation sand near the wellbore using resinous material.
4. Inject resin-coated gravel into the perforations to pack and stabilize the perforations.
Copyright 2007, , All rights reserved
FLOW RATE, Q
BOTT
OM
HO
LE F
LOW
ING
PRE
SSUR
E, P
wf
Pr
00
CRITICAL SAND FREE OIL RATE
OUTFLOW(CONTROLLED)INFLOW
CONTROLLING PRODUCTION RATES
CRITICALDRAW-DOWN
MEASURES TO CONTROL SAND PRODUCTION
Copyright 2007, , All rights reserved 17
Methods for Sand Control
Screnless
With Screen
Copyright 2007, , All rights reserved 18
Screenless Methods for Sand Control
In-situ consolidation Use of resins to consolidate formations.
Resin-Coated Gravel Injection of pre-coated gravel.
Copyright 2007, , All rights reserved 19
Methods for Sand Control using Screen
Gravel Pack Natural Sand Pack (NSP) Frac & Pack (Frac-n-Pack, Frac-Pack, StimPAC*)
* - mark of Schlumberger
Copyright 2007, , All rights reserved
MECHANISMS OF MECHANICAL RETENTION
GRAVEL
SAND
GRAVEL
SAND
BRIDGING FILTER-SIZE RETENTION
THE WHOLE IDEA BEHIND GRAVEL PACKING IS THAT THE GRAVEL MAY BE SIZED TO EFFECTIVELYRETAIN THE FORMATION SAND AND THE SCREEN MAY BE SIZED TO RETAIN THE GRAVEL
MEASURES TO CONTROL SAND PRODUCTION(GRAVEL PACK)
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MECHANICAL SAND RETENTIONMEASURES TO CONTROL SAND PRODUCTION
INSIDE CASINGGRAVEL PACK
OPEN HOLEGRAVEL PACK
UNDERREAMEDOPEN HOLE
GRAVEL PACK
UNDERREAMED CASING
GRAVEL PACKSCREEN LINERIN OPEN HOLE
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PERMEABILITY REDUCTION AS A FUNCTION OF RATIO OF GRAVEL SIZETO FORMATION GRAIN SIZE (After Saucier)
dG50/dR50
K/Ki
0.2
0.4
0
0.6
0.8
1.0
14121086420 1816 20
dG50(optimum) = 5 or 6dR50
RULE
OF
THUM
B
Copyright 2007, , All rights reserved 23
Gravel Pack
Sand - Gravel - Screen
Copyright 2007, , All rights reserved
FORMATION GRAIN SIZE STATISTICAL DISTRIBUTION(Sieve Analysis)
0.01 0.001 0.00010
20
40
PARTICLE SIZE, INCHES
RETA
INED
WEI
GHT
, PER
CENT
AGE
10
30
Copyright 2007, , All rights reserved
FORMATION GRAIN SIZE DISTRIBUTION(Sieve Analysis Results)
1.0 0.1 0.01 0.001 0.0001
100
2030405060708090
100
GRAIN DIAMETER, INCHES
CUM
ULAT
IVE
PERC
ENTA
GE
BY W
EIG
HT
DR50
DG50(optimum) = 5DR50
Copyright 2007, , All rights reserved
OPTIMUM GRAVEL SIZE DIAMETER AND OPTIMUM SCREEN SIZE
DG50(optimum) = 5DR50
1.0 0.1 0.01 0.001 0.0001
100
2030405060708090
100
GRAIN DIAMETER, INCHES
CUM
ULAT
IVE
PERC
ENTA
GE
BY W
EIG
HT
DR50
RESERVOIR
COMMERCIALGRAVEL
DG50
DGmin
DLINER SLOT = 0.5DGmin(*)
(*) FOR SCREEN LINER IN OPEN HOLE DLINER SLOT = 2xDR10 FOR NONUNIFORM SANDAND = DR10 FOR UNIFORM SAND
Copyright 2007, , All rights reserved
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. βG=bkG
-a
Sand/Gravel US Mesh Median Porosity Permeability ________________________Size(in.) Size Dia.(in.) (%) (mD) a b____________________________________________________________________________________________________0.006 ----- 0.017 40/100 0.0120.008 0.017 40/70 0.0130.010 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 0.0350.033 0.066 12/20 0.0500.039 0.066 12/18 0.0530.043 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 17x105- 1.24 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
Copyright 2007, , All rights reserved
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 TRAP
5. SAND BAILERSNot recommended
Copyright 2007, , All rights reserved 30
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
Copyright 2007, , All rights reserved 31
Sample collection
size
%
size (log)%
cum
ulat
ive
bail sample (high end)core samplebail sample (low end)
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GRAVEL PACK PLACEMENT
(Washpipe raised)
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GRAVEL PACK EVALUATION
Copyright 2007, , All rights reserved
EXERCISE
solution
_________________________________________________________________U.S.sieve Grain Weight
CumulativeNumber diameter retained Weight weight(mesh) (in.) (gm) percent percent_________________________________________________________________8 0.093012 0.066116 0.046920 0.033130 0.0232 0.25 1.4 1.4
40 0.016550 0.0117 0.79 4.3 5.7100 0.0059 2.81 15.4 21.1
140 0.0041 3.25 17.8 38.9200 0.0029 4.10 22.5 61.4270 0.0021325 0.0017 4.52 24.8 86.2Pan 2.52 13.8 100.0
Totals 18.24_________________________________________________________________
Well 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:
Suggest gravel and screen for gravel pack design for the well.
Copyright 2007, , All rights reserved 35
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
Copyright 2007, , All rights reserved 36
Gravel Pack Preparation
Always In OH, clean mud cake prior running screen In CH, ensure that all perforations are open and clean Clean tubing prior to any pumping
Copyright 2007, , All rights reserved 37
Internal gravel pack
Reliable drilling and completion methodologies
Requires efficient perforation system
Easier workover compared to EGP
Isolate production from undesirable zones
Poor perforation pack may lead to low productivity
Cased Hole Considerations
Copyright 2007, , All rights reserved 38
External gravel pack
Open Hole Considerations
Can 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
Copyright 2007, , All rights reserved 39
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 casing-screen.
Copyright 2007, , All rights reserved 40
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.
Copyright 2007, , All rights reserved 41
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 casing-screen.
Copyright 2007, , All rights reserved 42
Formation Analysis
Lithology, definition of fluids Granulometry, selection of gravel size
Copyright 2007, , All rights reserved 43
Fluids Compatibility
potential damage by fines migration (clays) formation cores are often unavailable inference from lab studies on similar formations requires comprehensive clays analysis of the samples
Copyright 2007, , All rights reserved 44
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
Copyright 2007, , All rights reserved 45
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.
Copyright 2007, , All rights reserved 46
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
Copyright 2007, , All rights reserved 47
Filtration
All fluids must be filtered– preferably at well site; avoid contamination in tanks and
transports Brines must be filtered at 2 μ Gels must be filtered at 10 μ
– 15/64 in to 3/8 in choke at 500 psi – estimate 10% reduction in viscosity
Copyright 2007, , All rights reserved 48
Damage caused by solids
A (2.5 ppm)
C (94 ppm)
D (436 ppm)
Per
mea
bili
ty (
md)
Volume Injected (gal/perf)
500
100
50
100 0.02 0.04 0.06 0.08 0.10
(A) Bay Water FilteredThrough 2um Cotton Filer
(B) Bay Water Through 5um Cotton Filter
(C) Produced Water Untreated
(D) Bay Water Untreated
B (26 ppm)
Copyright 2007, , All rights reserved 49
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
Copyright 2007, , All rights reserved 50
Screen, blank pipe & wash pipe
Screen length: 5 ft above and 5 ft below perforationsScreen OD: gap of 1-in per sideWash pipe OD: very close to screen IDBlank pipe OD: slightly less than screenBlank pipe ID: same as screen
1-in
wash-pipescreen minimum gap
blank pipe
screen
Copyright 2007, , All rights reserved 51
Liners or Screens ?
primary control onlyslots erosion
welding might corrodepressure loss across slots
cost can be highsmall fluid area
large flow areaun-restricted flow
robustenhanced control low cost
Wire Wrapped Screens
Slotted Liners
Copyright 2007, , All rights reserved 52
The ideal gravel pack
Complete packing with a properly sized high-permeability 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 fluid-loss pills.
Copyright 2007, , All rights reserved 53
Poor gravel pack placement
PerforationPotential for
production lossOpen Hole
Potential for production loss and/or screen failure (erosion)
Copyright 2007, , All rights reserved 54
Poor interface Gravel / Sand
Reduced pack permeabilityPotential for production
loss
Copyright 2007, , All rights reserved 55
Matrix damage
Invasion of the matrix by treatment/completion fluids
Potential for production loss
Copyright 2007, , All rights reserved 56
Damage zone
Perforation Crushed ZonePotential for
production lossOpen Hole Filter Cake
Potential for production loss
Copyright 2007, , All rights reserved 57
Gravel pack damage
Residuals from the treatment fluidPotential for production
loss
Copyright 2007, , All rights reserved 58
Multi-zone treatment
12840
12860
12880
12900
12920
12940
12960
12980
13000
13020
0 5 10 15 20
12840
12860
12880
12900
12920
12940
12960
12980
13000
13020
1 10 100 1000
0100020003000400050006000700080009000
10000
0 10 20 30 40 50 60
Time (minutes) P
ress
ure
(psi
)
0
2
4
6
8
10
12
14
16
Rate or C
onc. (bpm or ppa)
Surface Pressure
Rate
Conc.
4500
5000
5500
6000
6500
7000
7500
8000
0 10 20 30 40 50 60
Time (minutes)
P
ress
ure
(psi
)
130
140
150
160
170
180
190
Temperature (D
eg F) BHP Upper and Lower
Temp. Upper Gauge
Temp. Lower Gauge
Copyright 2007, , All rights reserved 59
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)
Copyright 2007, , All rights reserved 60
Two zones (lower wet)
1 0360
1 0380
1 0400
1 0420
1 0440
1 0460
1 0480
1 0500
1 0520
1 0540
0 50 1 00 1 50
10360
10380
10400
10420
10440
10460
10480
10500
10520
10540
0.1 1 1 0 1 00
Wet Sand
0
1000
2000
3000
4000
5000
6000
0 20 40 60
Time (min)W
ell P
ress
ure
(psi
)
0
5
10
15
20
25
30
Rate (bpm) Conc (ppa)
Copyright 2007, , All rights reserved 61
Multi-zones results
Complete Packs of All Zones Significant Completion Cost
Savings Elimination of Kill Pills Better Production
27 f t
0.7 in.
140 lbs/ f t
Recommended