Thermodynamic Behavior Description of a Reservoir Fluid by Using Cubic Equations of State

Reservoir fluid properties are important data in the calculation of many aspects of production and reservoir engineering. These properties are critical for efficient reservoir management throughout the life of the reservoir, from discovery to abandonment. Basically, the sequence followed in fluid modeling begins with collecting the samples from the reservoir, analyzing the samples and then developing the mathematical models that describe the thermodynamic behavior of the fluid. This study is interested in estimating the physical properties and prediction of the phase behavior of a reservoir fluid. The prediction was done by using Winprop of CMG® software which has a regression technique to tune the pressure-volume-temperature (PVT) data and phase behavior of the reservoir fluid. Two types of cubic equation of state (EOS) were used in this study. The results of this study showed that Peng‒Robinson (PR) equation was more accurate than Soave‒Redlich‒Kwong (SRK) equation in predicting the phase behavior of the fluid although the calibration process by SRK model was better in most of the experiments than PR model by observing the extent of convergence between the real (experimental) data and the data obtained from the simulation.