A study of improved recovery by vaporization/condensation process due to elevating temperatures in hydrocarbon reservoirs

A simulation of vaporization/condensation process was conducted to study the effect of the process on the gas enrichment and overall recovery of a low density crude oil.

The simulation begins with the identification of the most suitable equation of state model to characterize vaporization/condensation process. This was accomplished by simulating the constant volume depletion test and constant composition expansion test using three equation of state models and comparing the simulation results with the available experimental data. The equation of model, which predicted the constant volume depletion data most accurately, was selected to be used further in the study. The Peng-Robinson equation of state was found to be most accurate in predicting the experimental data.

The vaporization/condensation process was characterized by employing a combination of constant volume depletion test simulation and flash calculations using the selected equation of state. The entire characterization of vaporization/condensation process was performed on WinProp, a phase property program.

The vaporization/condensation process was found to be feasible as it was resulting in gas enrichment and increase in liquid saturation. These results were much more pronounced when conducted the vaporization/condensation at the high pressure and high vaporization temperature. Therefore, it was concluded that the vaporization/condensation may result in additional recovery if carried out at high reservoir pressure and high vaporization temperature.