Imbibition Displacement Efficiency of Chang 6 Reservoir in Yanchang Oilfield
Water injection development is the main technology to improve recovery rate of the ultra-low 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 Yan-chang Oilfield as the research object,heavy water and no water kerosene as the experimental medi-um,the study uses nuclear magnetic resonance technology to carry out spontaneous imbibition,imbi-bition 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 in-creases,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 de-creasing,the final oil-driven efficiency is 37.73%;the static contribution rate of spontaneous imbi-bition 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 signifi-cant in improving the recovery rate of water-driven oil in ultra-low permeability reservoirs.
ultra-low permeability reservoirspontaneous imbibitionwater-driven oilnuclear magnetic T2 spectrum
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