PROPERTIES OF BLACK OILS - Petroleum Reservoir Fluid Property Correlations - page 72

The second derivative on the right-hand side of equation (3.17c) was
obtained using equation (3.19d).

(3.17f)

The third derivative on the right-hand side of equation (3.17c) was
obtained using equation (3.19f).

(3.17g)

where

(3.17h)

.

Values of oil formation volume factors, B o , for use in equation (3.16a)
can be obtained with either equation (3.21a) or (3.21b) as appropriate.
Values of gas formation volume factors, B g , for use in equation (3.16a)
may be calculated with equation (2.12) with z-factors, z , obtained with
equations (2.4)-(2.8). This procedure requires values of the specific
gravities of the reservoir gas, γ gR , which can be estimated at pressures of
interest using equation (3.25).

Densities of Reservoir Oils

There is a change in slope at the bubblepoint pressure of a plot of
reservoir oil density versus reservoir pressure. This slope is negative
for pressures less than bubblepoint pressure and positive for pressures
greater than bubblepoint pressure. A set of correlation equations will
be used for estimating values of this property at pressures less than
bubblepoint pressure. An equation based on the definition of the