A Case Study of Black oil PVT Modelling with Differential Liberation Expansion (DLE) Analysis and Standing Correlations

Abstract

This study investigates the Pressure, Volume, and Temperature (PVT) modeling of black oil using Differential Liberation Expansion (DLE) analysis and Standing correlations. Black oil, characterized by its complex fluid properties, presents significant challenges in reservoir management and production optimization. Black oil samples were collected for analysis. The PVT analysis was carried out at Reservoir Fluid Laboratory, Port Harcourt. Oil samples were collected from the Q oil field. The PVT analysis results were correlated to validate the bubble point pressure (Pb), oil isothermal compressibility, (Co), oil formation volume factor (Bo), and the oil viscosity (mo. The PVT report gives Po = 2000 psi while the Standing Correlation gives Pb = 1934.271 psi a difference of 65.7 psi, i.e. 3.3% and solution gas/oil ratio 647.3 SCF/STB while the Standing Correlation gives 671.03 SCF/STB a difference of 3.5%, oil formation volume factor (Bo) of 1.456 reses. Bbl/STB while standing correlations give (Bo) of 1.0675 res bbl/STB a difference of 3.6%. The isothermal compressibility of the oil ranges from 10.12 x 10-6 psi-1 at P < Pb (at 4500 psi) to 4.1309 x 1018 cp at 15 psi. The conclusion is that Gas began evolving at 2000 psig and increased as the pressure decreased. Also, it was noticed that at a high pressure of 4500 psig the black oil viscosity was low at 0.54 cp while at a lower pressure of 15 psi the viscosity recorded was higher (1.38 cp). The crude is of high viscosity, with an average absolute error = 3.5% (0.035). The reservoir contains heavy crude oil with an API rating of 30.