Compositional Streamline Simulation of CO2 Flooding in Low Permeability Reservoirs

Abstract

The theory of CO2 flooding is getting more matured and completed with mounting field practices of CO2 injection in China. CO2 flooding is not only useful to the development of low permeability reservoirs, heavy oil reservoirs, and tight sandstone reservoirs but also benefit for CO2 capture and geological storage, which mitigated the greenhouse effect. This paper presented the compositional streamline model of CO2 flooding based on CO2 displacement mechanism. The model adopted the accurate and fast streamline method to solve the numerical model according to the change of fluid compositions. The model was modified considering the influences of gravity, compressibility, and dynamic miscibility by introducing operator splitting-up theory, source–sink term, and blending factor. The reliability of the model was verified by comparing with Eclipse. Cai9 Xishanyao reservoir was selected as the application example, and the compositional streamline model was established. The streamline distribution and migration of CO2 flooding in the reservoir were described quantitatively, and the effect of CO2 EOR was evaluated. The study is worth popularizing in the development of CO2 flooding in China.