EVALUATION OF EMPIRICAL PVT CORRELATIONS AND EOS TUNING TO MODEL LIBYAN CRUDE OIL PROPERTIES USING PVTi SOFTWARE

Abstract

 Understanding the PVT properties is very important to many kinds of petroleum determinations such as calculations of reservoir fluid properties, expect the future performance, selection of enhanced oil recovery methods, and production facilities design. Predict forecasting the reservoir fluid properties through empirical models have been increased during the last decade by knowing reservoir pressure and temperature, oil API gravity, and gas gravity. Correlations are used whenever experimentally derived PVT data are not available and data from local regions are expected to give better approximation to estimated PVT values. In this paper, complete PVT lab experiments were done and then evaluate the most frequently used empirical black oil PVT correlations for application in the Middle East. Empirical PVT Correlations for Middle East crude oil have been compared as a function of commonly available PVT data. Correlations have been compared for: bubble point pressure; solution gas oil ratio, oil formation volume factor, and oil viscosity. After evaluating the Empirical correlations the crude sample was characterized using different EOS to arrive at one EOS model that accurately describes the PVT behavior of crude oil produced. The multi-sample characterization method is used to arrive at one consistent model for crude oil for the whole reservoir. The fluid sample is first analyzed for consistency to make sure that they are representative of oil produced, and then it is used to obtain parameters for EOS model. The tuning procedure for the EOS is done systematically by matching the volumetric and phase behavior results with laboratory results. Results showed some correlations give good results and can be used with Libyan oil and some give high percentage of error. For EOS all of them need tuning because mismatching with lab data but after regression a very good match of PVT properties predicted are getting.