The Optimization Technique of Enhancing Recovery Efficiency in Zhongyuan Oilfield

Field tests have been made on CO2 stimulation,N2 drive,air injection displacement,synthetic polymer flooding,cross-linked polymer flooding and microbial oil recovery successively.Normal tertiary oil recovery isn′t fit for Zhongyuan oilfield with high reservoir temperature and formation water salinity.The techniques of enhancing oil recovery in Zhongyuan oilfield are optimized,and geologic and development features and current recovery condition of different types of oil reservoirs of Zhongyuan oilfield are summed up.After the analysis of technique potential,it draws the conclusion that CO2 miscible flooding,natural gas immiscible flooding first and then chemical flooding are fit for Zhongyuan oilfield from the reservoir condition and oil nature.Research shows that recovery efficiency can be enhanced by 11.1percentage point to 40.5% in Zhongyuan oilfield by integrated waterflooding adjustment and gas drive.Among them,increased recoverable reserves are 3841×104t and enhanced oil recovery is 7.4 percentage point by integrated waterflooding adjustment,and improved oil recovery is 3.7 percentage point by tertiary oil recovery.The direction and thinking for enhancing oil recovery in Zhongyuan oilfield are summarized that enhancing oil recovery by water flooding is still the key of current development in Zhongyuan oilfield.In the future,the main direction include restructuring development layer series,strengthening development of bad layers,improving waterflooding recovery of reservoir,developing mating technology of water plugging and profile controlling,improving waterflooding control degree and gas driving.