Experimental study on feasibility of CO2 miscible flooding in offshore low permeability reservoirs
Lufeng Sag in the offshore Pearl River Mouth Basin is rich in low-permeability and ultra-low permeability reserves.It is difficult to develop by water flooding,and the demand for gas injection development is urgent.CO2 flooding is one of the main technologies to enhance oil recovery.However,there is little application in the comprehensive utilization of offshore CO2.Taking L oil reservoir in Lufeng Sag as an example,this paper conducts the CO2 flooding mechanism experiment with crude oil from the target reservoir and the CO2 flooding effect evaluation experiment with a long core.This paper focuses on analyzing the changes in crude oil phase characteristics before and after CO2 injection and researching the flooding effect of different development methods to provide a basis for the feasibility of CO2 flooding in target oil fields.The experimental results show that CO2 flooding can effectively improve the development effect of low permeability reservoirs,the enhanced oil recovery could be increased by 11.75％ compared with water flooding,and water alternating gas flooding can be used as a technical means for later CO2 flooding to prevent channeling and further enhance oil recovery.The experimental research results provide technical support for CO2 injection development of offshore low permeability reservoirs.
CO2low permeability reservoirenhanced oil recoveryinjection and production parameterswater alternation gas
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