Application of a regression-based EOS PVT program to laboratory data

An equation-of-state (EOS) based PVT program was applied in matching laboratory PVT data for three published and nine additional reservoir fluid samples. The paper includes laboratory test data for the nine samples. The paper describes PVT program features, especially regression, which the authors find conducive to rapid determination of EOS parameter values necessary in matching data. With regression, both the Peng-Robinson and Zudkevitch-Joffe Redlich-Kwong EOS give comparable and generally good agreement with laboratory data. Without regression or significant adjustment of EOS parameters, neither EOS adequately predicts observed reservoir fluid PVT behavior. The EOS tuning approach described and illustrated here utilizes a small degree of C7+ fraction splitting. The agreement of these EOS results with data compares favorably with that obtained in previously published studies which utilized extensive, tuned C7+ splitting.