Block H1 is a general heavy oil block,and after carrying out several rounds of profile control and oil placement,it has obvious effect on enhancing oil recovery.With the injection of large dosage of oil placement profile control agent,the pressure is maintained at a high level in the late stage,the water content continues to rise,while the water absorption capacity of the injected wells decreases,the liquid production capacity of the wells decreases,the production decreases,and there is an urgent need for the effective development of the replacement technology.In order to further improve the development status quo,the indoor experiments were designed to inject viscosity reducer to further improve the recovery rate after the deep profile control and oil displacement.Through a large number of indoor experiments,the viscosity reduction agent JN-1 with good viscosity reduction and interfacial activity was screened out,the viscosity reduction rate was up to 82.0%,the oil-water interfacial tension decreased to 4.72×10-3 mN·m-1 when the mass fraction reached 0.2%.Indoor physical modeling experiments showed that,after injecting 0.3 PV oil placement profile control agent,continuing to inject 0.2% viscosity reducing agent of 0.3 PV,the residual oil could be fully activated,and the recovery rate could be further increased by 16.8%.Pilot test was carried out in 4 well groups on site,designed inject viscosity reducer mass fraction was 0.2% and the inject slug was 0.14 PV,the average daily oil increase of a single well was 0.8 t after injection,and the comprehensive water content decreased by 6%.
关键词
普通稠油油藏/调驱/降黏/提高采收率
Key words
Common thick oil reservoir/Profile control and oil displacement/Viscosity reduction/Enhanced oil recovery
维普
万方数据