低渗透油藏大都具有边底水、油水过渡带较大，对储量及产量有重要影响。油气成藏与注水开发过程驱替机理不同，传统开发理论均没有考虑这些差异：一是油气成藏过程中驱替毛管力控制油水分布，注水开发过程（假设岩石亲水）吸吮毛管力控制油水分布；二是过渡带中毛管力和相对渗透率曲线与初始饱和度、驱替速度等有关，即过渡带中不同高度上毛管力和相对渗透率曲线不同，而传统计算只用初始饱和度下的毛管力及相对渗透率曲线，导致低渗透油藏数值模拟动态预测与实际差别较大。本课题创新性研究内容如下：(1)研制具有自主知识产权的地下驱替、吸吮毛管力曲线测试仪器；(2)研究地下不同渗透率岩心驱替毛管力曲线，不同渗透率、初始饱和度下的吸吮毛管力和相对渗透率曲线变化规律及特征；(3)研究驱替速度对毛管力曲线影响规律。构建考虑岩石渗透率、初始饱和度等因素影响的新型毛管力和相对渗透率曲线形式，为油藏数值模拟、油藏工程计算提供可靠数据支撑。

The oil-water transition zone can be huge in low permeabile reservoirs with edge/bottom water, and the oil reserve and production in which takes great part of the total oil reserve and prodution of the whole reservoir. Formation of the oil and gas reservoir holds a different mechanism from the water flooding developing process. The drainage capillary pressure curve controls the oil/water distribution when the reservoir formates, while in the water flooding process the capillary pressure curve controls the oil/water distribution (supposing the formation rock is water wet). In addition, the capillary pressure curves and the relative permeability curves in the transition zone is related to the initial water saturation and the drainage velocity, which differs in the shape of the traditional capillary and relative permeability curves.The traditional capillary and relative permeability curves(the beginning water saturation is initial water saturation Swc) are commonly uesd in numerical simulation calculaitons, which brings great influence to the OOIP and production calculation. The innovative research of this subject focuses on: (1) Developing the neotype instrument for determining underground drainage capillary pressrure curves and the imbibition capillary pressure curves. (2) Determining the oil–water drainage capillary pressrure curves, the imbibition capillary pressure curves and relative permeability curves with different initial water saturation in reservoir condition of low-permeabile reservoirs with different permeabilities. (3)To study the influence of the drainage velocity on the capillary pressure curves. The purpose for this study is to give accurate drainage capillary pressrure curves, the imbibition capillary pressure and relative permeability curves based on gas permeability and initial water saturation etc. for reservoir simulation and calculation.