Page 200 - Petrophysics

PERMEABILITY-POROSITY WLATIONSHIPS 173

Figure 3.48. LPykstra-Parsons Coeflcient for well HBK5 (Homogeneous Reservoir).

This formation is slightly heterogeneous, but it can be treated as
homogeneous for reservoir simulation purposes.

Average Porosity
Amp, Bass, and Whiting 1171 showed that the histogram distribution
is also an excellent representation of porosity data obtained from core
analysis. Most porosity histograms are symmetrical about the mean value,
as shown in Figure 3.49. For classified data, i.e., arranged in increasing
or decreasing order, the arithmetic mean porosity is given by:

(3.128)

where:

Cpi = porosity at the midpoint of range, fraction
fi = frequency for porosity range, fraction
n = number of porosity ranges

For unclassified data, the arithmetic mean porosity is:

(3.129)
n
i=l