Abstract:

In view of the characteristics and challenges in developing the eastern mature oilfields of Sinopec， the study focuses on major progress made in research of enhancing oil recovery （EOR） technologies such as water flooding， chemical flooding， thermal recovery of heavy oil and CO₂ flooding， and introduces the application effects. For water flooding， focus is put on improvement of local injection-recovery relation， being combined with separate intelligent separate-layer injection and production technology， and pressurized water injection experiment is carried out in ultra-low permeability reservoirs. For chemical flooding， the binary surfactant/polymer flooding and the heterogeneous phase combination flooding （HPCF） have been developed and applied， with calcium/magnesium-tolerant agents developed for oil reservoirs with high temperature and high salinity. In terms of heavy oil reservoirs， compound viscosity-reducing flooding has been implemented in reservoirs with low displacement efficiency， H（horizontal well）+D（viscosity reducer）+C（CO₂）+S（steam） technology in deep ultra-heavy oil reservoirs， H （horizontal well）+D（viscosity reducer）+N（N₂）+S（steam） technology in shallow ultra-heavy oil reservoirs， chemical steam flooding in deep heavy oil reservoirs. As for CO₂ flooding， long-effect soaking and large slug injection technology has been put into effect in high-permeability reservoirs with high water cut； high-pressure and low-rate injection and alternate injection of water and gas from different wells in low permeability/ultra-low permeability reservoirs； and asynchronous cyclic injection and production in tight reservoirs. Analysis of the progress mentioned above serves for indicating the development direction of EOR promotion in different types of reservoirs.

Key words: ultra-high water cut, high temperature and high salinity, chemical flooding, thermal recovery of heavy oil, CO₂ flooding and storage, enhanced oil recovery （EOR）