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