Advanced Compositional Simulation of Carbon Dioxide Processes

Compositional simulators have become essential modelling tools for CO2 processes in the Petroleum Industry. Their evolution has enabled the models to represent an ever increasing number of physical and chemical phenomena applied to discretized grid meshes that approach the cell-size used in geological modelling. The advances in computational power encourage the development of meaningful improvements and refinements that could not be possible in a recent past.;This research work has identified some important needs related to the increased efficiency and accuracy necessary for the design of enhanced oil recovery projects using CO2 and for the sequestration of CO 2 into saline aquifers. Both problems represent major concerns worldwide.;The improvements achieved in this research span across different modelling aspects. The numerical efficiency of the solution of compositional problems has been addressed. In doing so, three IMPSAT solution techniques are proposed and analyzed. The phase behaviour of hydrocarbon mixtures in the presence of CO2 has been enriched to take full account of the possible existence of two oleic phases in thermodynamic equilibrium with a gaseous phase inside the porous media. Improvements are also made in the characterization of brine in the presence of CO2. As a result, a new viscosity correlation is developed and tested. Improvements are also achieved in the assessment of CO2 solubility in brine.;The developments and implementations that resulted from the present research are verified with regards to applicability into two important problems of interest to the Petroleum Industry. The new developments and implementations indicated gains in the modeling capabilities of CO2 sequestration into saline formations. Similarly, these improvements are verified when applied to improved oil recovery with the injection of CO2. Both applications confirm the capability of current compositional simulators, enhanced with developments of this research, to properly model CO2 processes as required nowadays.