Page 135 - A Practical Companion to Reservoir Stimulation

PRACTICAL COMPANION TO RESERVOIR STIMULATION

EXAMPLE 1-3
whereas the dimensionless fracture conductivity is
Calculation of Effective Fracture Length
-. -
and Dimensionless Fracture Conductivity h7n
FCD = (0.2) (150) = 22 (for pnf = 1000 psi) (1-9)
A fracture with an actual length of 150 ft is in a highly
anisotropic medium where k,/k, = 0.05. Calculate the effec- and
tive fracture length and the dimensionless fracture conduc- 5800
=
tivity using the results of Example 1-2 and a reservoir permea- FCD = (0.2) (150) = 190(for~,,:~ 3000psi). (1-10)
bility equal to 0.2 md.
It is evident that acid fractures should be used in higher
Solution (Ref. Section 18-1) permea%ility reservoirs where length is less important than
The effective fracture half-length can be estimated from fracture conductivity. In low-permeability carbonate reser-
Eq. 18-41 voirs, propped fractures, with their much longer lengths, are
Xr = 150 (0.05)”4 = 71 ft, ‘ (1-8) indicated in spite of the solubility of the rock. This will be
demonstrated in later examples.

1-2