Comparative Analysis of Laboratory Measured and PVTP Software Data

Abstract

Cubic Equations of State (EOS), including the Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) models, are foundational in petroleum engineering for modeling the thermodynamic behavior of hydrocarbon systems. These EOS are widely used to predict phase behavior and Pressure-Volume-Temperature (PVT) properties, which are crucial for reservoir simulation, production forecasting, and enhanced oil recovery. However, their predictive accuracy diminishes when applied to complex fluids under High-Pressure, High-Temperature (HPHT) conditions or in the presence of heavy components. This study aims to evaluate the predictive performance of the PR and SRK EOS using PVTP software by comparing their simulation results with laboratory-measured PVT data from Nigerian crude oil samples. Key reservoir conditions, such as temperature, pressure, and fluid composition, were maintained consistently to ensure a reliable comparison. Simulations were conducted for key properties including bubble point pressure, oil formation volume factor (Bo), Gas-Oil Ratio (GOR), gas formation volume factor (Bg), and viscosity. Results show both EOS models performed adequately in predicting bubble point pressure, Bo, and GOR, especially near saturation conditions. However, significant deviations were observed in viscosity and Bg predictions, particularly at low pressures. In conclusion, while PVTP software provides reasonable estimates for most volumetric properties, its predictions for gas-phase parameters require further refinement for complex fluid systems.