PROPERTIES OF BLACK OILS - Petroleum Reservoir Fluid Property Correlations - page 74

The Witte and McCain-Hill procedures are modifications of
Standing's original set of correlation equations. 29 Witte modified the
Standing equation, which determines the density difference due to
thermal expansion from 60ºF to reservoir temperature, Δρ T , because
Standing did not have sufficient data at the lower densities and higher
reservoir temperatures to properly determine the density difference in
that region. The Witte equation is given in the McCain-Hill paper. 30
McCain and Hill modified the calculation of the apparent liquid density
of the surface gas, ρ a .
Labedi and Sutton proposed procedures that are entirely different
than those proposed by Standing. 31
Witte used less than 10% of the data of table 3-13 to develop his
equation for Δρ T ; McCain and Hill used approximately 90% of these
data in developing their equation for ρ a . Standing, Labedi, Sutton, and
Hanafy et al. apparently did not use any of these data.
The data set described in table 3-14 was sorted and divided into
eight subsets of just less than 100 lines of data each for each of the
important independent variables. In addition, the data set was sliced on
reservoir oil density from the data set. The results are in figures 3-16
through 3-19.
The successive alterations to the original Standing equations did
produce some improvement; however, all three versions give good
results. The calculated values of reservoir oil densities using these
equations are approximately as precise as the underlying data.
The common wisdom that the Standing correlation equations do
not give adequate results at low reservoir oil densities and high reservoir
temperatures is not verified by figures 3-18 and 3-19.