Improved K-value correlation for UAE crude oil components at high pressures using PVT laboratory data☆

In this paper, 732 high-pressure K-values obtained from PVT analysis of 17 crude oil and gas samples from a number of petroleum reservoirs in the UAE are used. Material balance techniques are used to extract the K-values of crude oil and gas components from the constant volume depletion and differential liberation tests for the oil and gas samples, respectively. These K-values are then correlated and the resulting correlation compared with published correlations. Comparisons of results show that currently published correlations give poor estimates of K-values for non-hydrocarbon and hydrocarbon components, while the proposed new correlation improved significantly the average absolute deviation for non-hydrocarbon and hydrocarbon components. The average absolute error between experimental and predicted K-values for the new correlation was 20.5% compared with 76.1% for the Whitson and Torp correlation, 84.27% for the Wilson correlation, and 105.8 for the McWilliams correlation. Additionally, the bubble point and dew point pressures are calculated for these 17 samples and compared with experimental values. The average absolute error in the saturation pressures for the new correlation was 6.08% compared with 56.34% for the Wilson correlation, 57.84% for the Whitson and Torp correlation, and 9.28% for the Peng–Robinson equation of state with default parameters.