Injection mode of CO_2 displacement in heavy oil reservoirs

摘要

CO_2 injection has been an important enhanced oil recovery method adopted at the later stage of oilfield development, and a series of studies and field experiments has been done in recent years. However, there are some problems in this process, such as viscous fingering, gravity override, channeling of CO_2 in heterogeneous reservoir. These challenging issues are closely related to the CO_2 injection ways. At present, it is at development stage and calls for more research on optimally choosing CO_2 injection methods to displace oil. This research mainly uses different CO_2 injection methods to displace oil, in order to optimally choose the CO_2 injection method that fit this experiment area, and does research on the effects and principles of CO_2 drive to enhance oil recovery. Compared with gas flooding and WAG, CO_2 foam greatly reduce the mobility of the injected gas and expand the sweep volume. This is consistently observed in the numerically simulated foam process at the field level.