Page 578 - Petrophysics
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CHARACTERIZING NATURAL FXACTURES 545
100
.-
v)
a
i
.-
>
.-
.I-
Q
>
$ lo
rn
E
=I
u)
u)
22
n
1
0.01 0.1 1 10
Time, hr
Figure 8.32. Pressure derivative group plotted against shut-in time.
SOLUTION
l(a) Conventional method
From Figure 8.31: aP = 15 psi, m = 25 psiflog cycle and Atid =
0.22 hrs
1. The average permeability of the formation is estimated from the slope
of the semilog straight line. Using Equation 8.75 yields:
162.6qpB0 162.6 (17000) (0.47) (1.74)
k= - = 78.6 mD
-
mh (25)(1150)
2. Fluid storage coefficient is estimated using Equation 8.74:
The storage coefficient of 0.25 indicates that the fractures occupy 25%
of the total reservoir pore volume.
