Page 510 - Petrophysics

478 PETROPHYSICS: RESERVOIR ROCK PROPERTIES

1490 ft 30 ft 2.5 ft

15 mD

200 mD
4 mD

Figure 7.19. A system of 3 radial segments in series.

SOLUTION

Figure 7.19 is a schematic diagram of the drainage system, where r, =
0.5 ft and re = (43,560 x 160/.n)0.5 = 1,490 ft. The average permeability
of this system is calculated from Equation 7.163:

This example illustrates how the beneficial effect of a successful acidizing
job is counteracted by the negative effect of improper well completion,
and how important it is to calculate accurately the average permeability
of reservoirs. If the well was completed properly without zonal damage,
the average permeability would have been:

/1.490\

or nearly double the permeability of the formation prior to acidizing and
well completion.