Page 474 - Petrophysics

442 PETROPHYSICS: RESERVOIR ROCK PROPERTIES

Figure 7.7. Skin zone.

wellbore damage) or the pressure increase (due to stimulation), Aps,
Aps = ( qscpBo >.
from the (pe - p,) or (p - p,) terms, where:

0.00708kh (7.72)

or by replacing the wellbore radius term, r,, by an effective or apparent
wellbore radius, rwa, which is estimated from [24]:

rwa = rWe-+ (7.73)

For example, ifthe well is damaged or stimulated, Equation 7.67 becomes:

0.00708kh(p - pw - Aps)
qsc = (7.74)
pBo(ln (re/rw) - 0.75 + 0.25f)

or:
O.O0708kh(P - pw)
4sc = (7.75)
pBo(ln (re/rwa) - 0.75 + 0.25f)

or, because In (re/rwa) = In (re/rw) + S:

(7.76)