Page 43 - A Practical Companion to Reservoir Stimulation

PRACTICAL COMPANION TO RESERVOIR STIMULATION

EXAMPLE C-2
As can be seen, the compressibility coefficient for an oil
Calculation of Total Leakoff Coefficient well can be a very effective means of leakoff control; for a gas
well it is not.
Assuming that the filter-cake leakoff coefficient is Cw, = 0.001 The total leakoff coefficient can be considered as a series
ft/6 and using the data in Table C-1, calculate the total of resistances, and thus
leakoff coefficient for both the gas-well and the oilwell data.
1 1 1 I
Solution (Ref. Section 5-7) CL - 0.001 +-+- 0.113’ (C-9)
0.01
From Eq. 5- 16, the viscosity control coefficient can be calcu-
C,, = 0.0469 {T
lated (this is the same for both the oil and the gas well): leading. to CL = 9 x for the gas well. For the oil well a
similar calculation leads to CL = 7.7 x

I k = lrnd I
= 0.01 ft I &n. Ap = 4000psi
~
~
From Eq. 5- 17, the compressibility control coefficient can = 0.12
be calculated. f$
For the gas well, I ct = 1.2 x 10-4 psi (gas well) I
C,. = (0.0374) (4000) I c, = 10-5 psi (oil well) I
,u = 0.025 cp (gas well)
(0.001) (0.12) (1.2 x
= 0.1 13. (C-7) p = 1 cp (oil well)
0.025
fiL = 1ocp
For the oil well,
Table C-1-Reservoir and fluid data for Example C-2.
{ (0.001) (0.12)
C,. = (0.0374) (4000)
1

= 0.005.

c-4