Phase Behavior of Several CO2 West Texas Reservoir Oil Systems

Current interest in miscible enhanced oil recovery methods has led to the use of compositional simulators to understand and predict the performance of such processes. Fluid property considerations are highly important from two standpoints: 1. An essential part of such a simulator is a means of predicting the complex phase equilibria likely to be encountered in such EOR processes. While reliable equations of state have been developed to calculate phase behavior in these processes, most often parameter adjustments are required to properly describe the COZ-reservoir oil systems. These adjustments require experimental data on systems of interest. 2. The evaluation of the physics required in such a simulator depends upon an understanding of the fluid properties that will be encountered. The relative importance of viscous fingering, gravity override, physical dispersion and low interfacial tension effects must be assessed through interpretation of laboratory CO2 coreflood and pilot field studies. This requires an understanding of the phase equilibria encountered in such processes and the ability to make reliable predictions.