Page 302 - Geology and Geochemistry of Oil and Gas

MODELS OF DYNAMIC GEOLOGIC SYSTEMS 263
rock properties using the following equations:

Porosity f ¼ f Z 1 (11.97)
o
4
Permeability k ¼ k o ðZ 1 Þ (11.98)
Density g ¼ g ð1 f Z 1 Þ (11.99)
ma o
where f and k o are, respectively, the initial values of porosity and permeability
o
before compaction of sediments, g ma is the density of matrix of consolidated rocks,
and Z 1 is equal to:

n ," n !#
Y Y
Z 1 ¼ x i 1 f o 1 x i ¼ Z=½1 f ð1 Zފ (11.100)
o
i¼1 i¼1
is the relative change in porosity: f=f .
o
The results of the numerical simulation show that the modeling coefficients x i
represent adequately the influence of many geological factors on the petrophysical
properties of rocks (Fig. 11.30).

Fig. 11.30. Results of numerical simulation of Mesozoic reservoir-rock properties. (a) Porosity, (b) per-
meability, (c) density. 1 – Average curve, 2 – confidence limits. (After Buryakovsky, 1993.)