延长油田长6储层渗吸驱油效率实验研究

Imbibition Displacement Efficiency of Chang 6 Reservoir in Yanchang Oilfield

注水开发是特低渗油藏提高采收率的主要技术,水驱油过程中渗吸作用对水驱油效率贡献大小,对有效提高水驱油效率并最终提高原油采收率至关重要。以延长油田长6组油藏真实岩心为研究对象,重水和无水煤油为实验介质,采用核磁共振技术,分别开展了自发渗吸、渗吸驱替、驱替实验研究,并定量描述了渗吸作用对水驱油效率的贡献值。结果表明:静态条件下,随自发渗吸时间增加,驱油效率逐渐增大,最高达到37.11%;渗吸后再以不同驱替速度进行驱替,增大驱替速度,有效增加了驱替过程对水驱油效率的贡献,驱替速度0.06 mL/min时,最终驱油效率为45.68%;在岩心饱和油状态下直接驱替时,随注入速度的增大,驱油效率呈现出先增大后减小的趋势,最终的驱油效率为37.73%;自发渗吸静态贡献率最大为37.11%,动态贡献率最小为7.95%,不同条件下驱油的自发渗吸平均贡献率为22.53%。该研究成果对于特低渗油藏水驱油提高采收率具有借鉴意义。

Water injection development is the main technology to improve recovery rate of the ultralow permeability reservoir,and the water-driven oil imbibition effect contributes to the efficiency of water-driven oil,which is very important in effectively improving the efficiency of water-driven oil and the ultimate recovery rate of crude oil.Taking the real core of Chang 6 Oil Reservoir in Yanchang Oilfield as the research object,heavy water and no water kerosene as the experimental medium,the study uses nuclear magnetic resonance technology to carry out spontaneous imbibition,imbibition displacement,and displacement experimental research,as well as the quantitative description of the effect of imbibition on the efficiency of water-driven oil.The results show that under static conditions,with the increase of spontaneous imbibition time,the fuel-driven efficiency gradually increases,reaching 37.11%at the most;after imbibition ingests,the drive-off speed is increased,the drive-off process is effectively increased,and the final oil-removal efficiency is 45.68%when the drive-off speed is 0.06 mL/min;when directly driven under the state of core saturation oil,with the increase of injection speed,the efficiency of the oil drive shows the trend of increasing and then decreasing,the final oil-driven efficiency is 37.73%;the static contribution rate of spontaneous imbibition is 37.11%,the dynamic contribution rate is 7.95%at the least,and the average contribution rate of spontaneous imbibition under different conditions is 22.53%.The research results are significant in improving the recovery rate of water-driven oil in ultra-low permeability reservoirs.