Page 210 - Petrophysics
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PERMEAFHLITY-POROSITY REIATIONSHIPS 183
following equation is used to calculate permeability:
WBo
k = 162.6- (3.130)
mh
where: k = formation permeability, mD
q = flow rate, STB/D
m = fluid viscosity, CP
Bo = formation volume factor, bbl/STB
h = formation thickness
m = slope of the straight line, psiflog cycle
Other parameters obtainable from these type of tests are: degree of
formation damage around the wellbore, number and type of reservoir
boundaries, and degree of connectivity to other wells. A modern
technique for analyzing pressure data is based on the log-log plot
of pressure derivative (t*Ap’) versus time, as shown in Figure 3.56.
Using the Tiub’s Direct Synthesis technique the permeability is obtained
from [61]:
10000
al
.-
>
U
.-
Q
>
:
L
1000
2
3
u)
u)
2
n
m
100
2
a
u)
u)
2
n
10
0.01 0.1 1 10 100
Time
Figure 3.56. Pressure derivative plot showing infinite acting radialpow regime.
