Page 209 - Petrophysics 2E

182 PETROPHYSICS: RESERVOIR ROCK PROPERTIES

Practical information obtained from well testing includes permeability
along with porosity, reservoir shape, average reservoir pressure, and
the location of the reservoir boundaries, such as sealing faults, in the
vicinity of the well. The most common method for obtaining permeability
consists of plotting pressure data versus time on a semi-log graph paper
(e.g. Figure 3.54 for pressure drawdown test, and Figure 3.55 for pressure
buildup test). Upon determining the slope of the straight line, the

31 00

3000

2900
.-
u)
P
f 2800
n
2700

2600

2500
0.1 1 10
Time, t, hr

Figure 3.54. Semilog plot of pressure drawdown test.

850

800

-R 750
s
700

650

600
10000 1000 100 10 1
(t,+At)/At, h r

Figure 3.55. Semilog plot ofpressure buildup test (Hornetplot).