低渗透油藏CO_2驱注入方式优化

Injection optimization in CO_2 flooding for low permeability reservoir

根据吉林油田某低渗透区块的油藏条件,运用数值模拟方法研究不同驱替方式下的驱油效果。数模结果显示,交替驱替方式优于注水方式和连续气驱方式,能大幅度提高原油采收率。在交替驱过程中,气段塞和水段塞的先后顺序对采收率有显著的影响,气水交替驱优于水气交替驱,随着注气速度的增加,采收率的差值也逐渐增加。气水交替驱注入CO2能够和原油充分接触,越早注入CO2,对提高原油采收率越有利。该研究不仅为低渗透油田CO2驱油技术提供了理论基础,而且对于国家下一步进行CO2驱油和埋存潜力评价及规划具有重要的借鉴意义。

The displacement efficiency of different scenarios has been studied through numerical simulation based on the conditions of a low permeability reservoir in Jillin oilfield.The simulation results indicate that alternating flooding can significantly improve oil recovery compared with water flooding and continuous gas flooding.In the process of alternating flooding,the order of gas and water slugs has a notable impact on oil recovery.Gas-alternating-water flooding is superior to water-alternating-gas flooding.The recovery factor increases with the increasing of gas injection rate.In gas-alternating-water process,CO2 can fully contact with crude oil,and the earlier CO2 is injected,the more favorable for enhanced oil recovery.The research has provided theoretical basis for CO2 flooding in low permeability reservoirs as well as meaningful reference in evaluating and planning of CO2 underground storage in China.