Primary and secondary drive oil production mechanisms are coming short in meeting the ever increasing global oil demand. Currently, many tertiary recovery-EOR projects are in the design or implementation stage in many parts of the world to help meeting this extra global oil demand. Good number of these projects involves certain kinds of CO2 gas injection. To help match the technical results of these projects and their economic viability under the current oil prices, the industry should learn from the lessons of the available global field, pilot and laboratory technical evaluation experiences. This is to avoid unnecessary losses in time and money and to make the best incremental oil recovery possible.
To master the performance of CO2 flooding and provide accurate data for designing an oil development plan, a comprehensive investigation of CO2 flooding phase behavior and mechanisms based on laboratory study needs to be conducted. This is a challending prospect technically and economically. The results of a large number of CO2 gas injection laboratory technical evaluations have been reported in the literature. This paper tries to give a serious and comprehensive review of the past global experience of laboratory CO2-EOR flooding, and reports the best practices of laboratory technical evaluations and to highlight the uncertainties and limitations of these evaluations.
A large number of technical papers were reviewed to describe the laboratory experiments that are most performed for CO2 flooding evaluation. The main issues that could be addressed using laboratory technical evaluation are covered including PVT properties of different CO2-Oil mixtures, effect of Rock Pore Structure on CO2 Miscible Displacment, effect of WAG and Wettability on CO2-EOR Flooding, assessement of Asphaltene Deposition, and effect of Slug Size on Oil Recovery by CO2 Miscible Flooding and finally CO2 flooding in naturally fractured reservoirs. Finally, the paper reports on the proper utilization of any attainable laboratory data and its limitations.