Insights on equation of state modeling PVT experiments for deep volatile oil reservoir

AbstractAbstractAccurate prediction of the PVT properties and phase behavior plays an important role in developing volatile oil reservoirs. The objective of this study is to characterize volatile oil sample using our improved Perturbation from n-Alkane (PnA) method and validate the results by use of high-quality PVT experimental data from GT1 well through detailed PVT simulation. We implemented PnA method for reservoir fluid characterization and simulated all PVT experiments through an in-house programming package. We compared the modeling results to the experimental data and found that the equation of state (EOS) parameters characterized by the PnA method is able to describe the PVT properties and phase behavior of volatile oil very well. According to the PVT modeling results, we suggested that (1) constant volume depletion test for GT1 volatile oil can be replaced by differential liberation experiment, combined with the data obtained from reliable EOS calculations; (2) the amount of surface-produced condensate for a volatile oil reservoir is up to 4.5% OOIP depending on reservoir abandonment pressure. Therefore, for GT1 volatile oil, condensate production should be carefully evaluated throughout the entire development life-cycle in order to make an optimum design of surface processing facilities for condensate recovery.Keywords: equation of statephase behaviorPnA fluid characterizationPVT experimentvolatile oil AcknowledgmentsThe authors would like to gratefully acknowledge the financial support from the Prospective and Fundamental Science and Technology Project, PetroChina, ‘Study on Seepage Law Through Multi-Scale Media under Strong Stress in Deep/Ultra-Deep Reservoirs (Grant No. 2021DJ1002)’. We thank Research Institute of Petroleum Exploration and Development, PetroChina for permission to publish this paper. The support from the Department of Offshore Oil & Gas Engineering and CMG-CUP Joint Numerical Reservoir Simulation Laboratory at China University of Petroleum (Beijing) is also acknowledged.