Study On Enhanced Oil Recovery In Yong 8 Fault Block With Polymer Microspheres For In-depth Profile Modification

The matuared oilfield in high water cut stage are surferring increasing permeability heterogeneity with severely injected water channeling, leading faster decline in oilfield production. At this stage, the application of deep profile control to comprehensively improve the entire reservoir waterflood sweep volume is particularly urgent to reservoir recovery rate.Polymer technology for in-Depth Profile Modification reservoirs is far from matured, not mention that it is used for fault block reservoirs with not well-pattern networks. Here, however, polymer microspheres have achieved better effect in improving water-flooding performance and oil increasement in Yong 8 fault block in nearly three years..Based on analysis available data of coring and numerical simulation, remaining oil and distribution of underground presssure field of reservoirs after polymer flooding are well descriped.The distribution data of fluid field and presssure field allow the good judge of dominant channels,and provide a basis for overall plugging and pofile control. The D-2 and G-2 microspheres was evaluated and optimized for different permeable reservoirs in Yong 8 block of Dongxin Oil Production Plant by lab experiments including paralelled tube test, swollen test, and the selection of injection slug combination. The high concentration and small slug size of microspheres can obtain greater performance in profile control. The treatment process was well designed. The decrease of pressure drop and increase of fullness degree indicate success in treatment.This study open a way to enhance oil recovery for in-Depth Profile Modification fault block reservoir after waterflood heterogeneity, and provide experience and technical support in profile control for the same type of reservoir deep tone drive.