Near-Critical and Retrograde Phase Behavior of Gas Condensate Systems UsingEquations of State. Final Report, July 1991-February 1992

摘要

A large number of high pressure gas condensates and volatile oil reservoirs areinitially in the retrograde and near critical regions. The phase behavior predictions of such reservoir fluids using equations of state (EOS) is currently unreliable. The main goa of the research is to improve the predictive capability of EOS for reservoir gases. It has been learned that the interaction coefficient between the components decreases as the critical point is approached. Modeling such a decrease is the key to near-critical phase behavior calculations. In the study, the variation of the interaction coefficient is tied to phase compressibility. Such a model provides the desirable decrease in the liquid phase compressibility but increases the gas phase interaction coefficient as the critical point is approached. In future research, the deficiency should be overcome. On the whole, incorporation of the concept of interaction coefficient decrease (around the critical point) in phase behavior models will prove useful.