Work Process1. Estimate Stresses and
Pressures
2. Determine Fcd and FOI (Evaluate Various Proppants and
Frac Lengths)
3. Preliminary Proppant
Selection
4. Estimate Fracture
Geometrya) Young’s’Modulus
b) Sand/Shale σ
5. Fluid Loss – ‘C’ and Spurt
Loss
6. Fluid Selection –a) Apparent Viscosity (cps)
b) Basic Chemistry / Additives
7. Calibrate Model –Diagnosticsa) Fracturing Pressure
b) Temperature/RA Logs
c) Microseismic
8. Final Treatment Pump
Schedule
9. Operations / Perforating
FRACTURE DESIGN VARIABLESFLUID LOSS
H , E , C , KIc m , Q
Fluid Loss Mechanisms3 Fluid Loss Coefficients
Linear Flow ASSUMPTION
Viscosity Control, CI (or CV)
(Effect of Viscous “Bank”)
Reservoir Control, CII
Filter Cake Control, CIII (or CW)
)(
2
At
dACQLoss
C/t --> Low Loss Near Well
1020304050
0.05
0.10
0.15
0.20
0.2
0.4
0.6
0.8
TIME (min)
Q-Loss (bpm/100 sq. ft)C = 0.003 ft/min
V-Loss (bbl/100 sq. ft)
Fluid Loss
Matrix Fluid Loss “Behavior”
Most of
Fluid Loss
Near
Fracture
Tip
x (ft)
Q-L
oss (
bp
m/1
00 s
q.
ft)
20 40 60 80 100 120 140 160 180
0.05
0.10
0.15
C = 0.002 ft/mint = 30 min
Xf = 200 feet
1/2 the TotalFluid Loss
Fluid Loss Into Formation
CI , CII , & CIII
Lab Test For CW
8/22/2014Provided by Constien & Associates, Inc.
Dynamic Fluid Loss Cell
Formation
Filtrate
CW + “Spurt” Loss
Time (min)
Volume Lost/Unit Area Spurt Loss
Spurt Time
Lab Test Data For Cw
Slope --> Cw
Typical CW Values
0.0010.0020.0030.005 0.01 0.020.030.05 0.10.0001
0.0002
0.0003
0.0005
0.001
0.002
0.003
0.005
0.01
Permeability, k (md)
Wall Building Fluid Loss Coefficient C or C (ft/
min)III
WTypical Lab C Values - 150 °FW
Crosslink Cellulose
X-Link Guar Gum
Polymer Emulsion
X-Link Guar Gum + 5% Diesel
Combined Fluid Loss , CT
f
rI
pkC
m
0015.0
m
CtkpCII 0012.0
)( datalabfromCC wallIII
IIIIIIT CCCC
1111 BUT
Spurt Loss
• Strange Behavior
• “0” for low permeability (small pore
throat diameter) cases
• Increases with k
• Returns to “0” for high k formations
Behavior somewhat “statistical in nature
Spurt Loss Lab Data
0.10.20.5125102050
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
Permeability (md)
Spurt (gal/sq. foot)20 ppt (lb/M-Gal)
50
60
80 ppt (lb/M-Gal) gel
40
HPGX-Link Gel---------------125 deg F
Effect of Temperature on Cw
100150200250300
1
2
3
Temperature (deg F)
Temperature Effect on Cw
Water Base Fluids
Test at 80 deg F
Test at 125 deg F
Effect of Temperature on Cw
100150200250300
0.002
0.004
0.006
0.008
0.01
Temperature (deg F)
Cw (ft/min̂1/2) HPG Titinate X-Link Gel 30 lb gel data 40 lb gel data 50 lb gel data
Solid Lines = Cw (at 80 deg F) X (m)-1/2
W
Fluid Loss Additives
ONLY Two Types
- Solid
- Liquid (3 to 5% hydrocarbon)
Solids
- Used to reduce or eliminate spurt loss and
allow a wall cake to build
- Do NOT Reduce CW or CT
- Many flavors !
Liquids
- Used to reduce CW
- Wall cake MUST from first
Solid FLA --> Reduce Spurt
10 20 30 40
0.0005
0.001
0.002
0.003
0.005
0.01
FLA Concentration(lb or gal/M-Gal))
C Polymer-Resin Silica Flour Polymer-Silica-Clay Diesel (0.1 - 10 md)W
Solid FLA Guidelines
Particles sizes:
If > 1/2 of pore throat, solids will quickly bridge on the
face of the formation face
If < 1/3 of pore throat, solids will invade and will
probably cause fracture face damage
If < 1/7 of pore throat, solids will invade but will
probably not cause damage
For sandstones:
Pore throat in microns (est):
• Pt = permeability 0.5 (md)
Do Frc_Skl 1 7
Do Frc_Skl 1 8
•Use a Net Pressure (Pn) of 300 psi
•ΔP = (Pc+Pn) – Pr
•Diesel Concentration = 2%
Typical CW Values
Crosslink Cellulose Derivative
Crosslink Guar Derivative
Polymer EmulsionCrosslink Guar Derivative + Hydrocarbon
0.001 0.01 0.10.0001
0.001
0.01
Permeability, k (md)
Wall B
uild
ing
Lo
ss C
oeff
icie
nt
C (
ft /
m
in)
III
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