Page 44 - A Practical Companion to Reservoir Stimulation

FRACTURING FLUIDS AND PROPPANTS

EXAMPLE C-3
coefficient is halved if C, is halved and is doubled if C,, is
Leakoff Control Comparisons
doubled.
If the leakoff viscosity is 1 cp (0.1 of the value used in
Compare the total leakoff coefficient and control of it for Example C-2), then the viscosity control coefficient is equal
Example C-2 assuming that the wall coefficient is halved (5 x to 0.032 (as in Eq. C-6) and the total leakoff coefficient is
or doubled (2 x Repeat the calculation by equal to 9.6 x 10-4(a 7% increase from the value in Example
changing the leakoff viscosity from 10 cp to 1 cp and 100 cp. c-2).
Use the data for the oil well only. If the leakoff viscosity is 100 cp (10 times the value in
Solution (Ref. Section 5-7) Example C-2), then the viscosity control coefficient is equal
to 0.0032 and the total leakoff coefficient is equal to 7.6 X
The total leakoff coefficient, using the results from Eqs. C-6 10-4(.a 15% decrease from the value in Example C-2).
and C-8 and calculating it as in Eq. C-9, is equal to 4.7 x Thus, leakoff control is far more effective using a wall
(for C, = 5 x and 1.6 x (for C, = 2 x filter cake than by any other mechanism.
This is a substantial change from the leabff coeffi-
cient calculated in Example C-2. Essentially, the total leakoff

C-5