Connotation,mechanism,and practice of"3+2"significantly enhanced oil recovery technology in mature oilfields
Traditional chemical flooding projects typically adopt the"2 + 3"combination,which involves adjusting the water flood-ing well pattern before implementing chemical flooding.Due to the limitation in understanding and predicting residual oil,this method often leads to some low-yield and inefficient wells,and the low water cut period of chemical flooding is short,resulting in limited improvement in oil recovery.To address this,Shengli Oilfield innovatively proposed the"3 + 2"technology for signifi-cantly improving oil recovery through fundamental research and exploratory practice.This technique involves using the oil displace-ment system more effectively during chemical flooding to expand the swept volume,increase the displacement efficiency,and ad-just the dynamic heterogeneity.It actively cultivates and enlarges the dynamic remaining oil enrichment area("oil wall"),adjusts well pattern on time,reconstructs flow fields,balances injection and production,and efficiently produces the"oil wall".This maxi-mizes the extension of the low water cut period of the chemical flooding,achieving synergistic efficiency in tertiary and secondary oil recovery("3 + 2")and significantly enhancing oil recovery.Through extensive physical and numerical simulation studies,the suitability optimization mechanism of"well pattern-oil displacement agent-remaining oil"to enhance oil recovery was clarified.The technology was applied in Ed35 of District 2 in Shengtuo Oilfield.It is predicted that the low water cut period will extend from three years to eight years,and the final oil recovery will reach 60.5%,which is 7.5 percent higher than the original plan by optimizing the"3 + 2"well pattern adjustment,oil displacement system,injection parameters,etc.This technology is critical to significantly im-proving oil recovery in mature oilfields and can provide guidance and reference for similar reservoirs in China and abroad to extend the peak oil production rate period during chemical flooding.
chemical floodingdynamic optimization adjustmentpeak oil production rate periodcollaborative efficiency en-hancementsignificantly enhanced oil recovery
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