裂缝性油藏注水井压降试井解释方法及应用

摘要

为了更加准确地描述裂缝性油藏注水井的动态特征,得到更多关于地层和测试井的可靠信息,基于Buckley-Leverrett饱和度分布方程,建立了裂缝性油藏注水井压降试井解释模型,并对模型进行了数值求解,获得了裂缝性油藏注水井压降试井典型拟合图版.根据压降导数曲线特征,将流动过程划分为7个流动段:井筒储集效应阶段、表皮效应阶段、基质向裂缝窜流阶段、水区径向流阶段、油水两相区响应阶段、总系统径向流阶段和边界响应阶段.油、水黏度差异会导致双对数曲线上翘建立的试井解释模型可计算注水前缘的位置,分析注水井周围地层信息及边界情况.研究结果对注水井的动态评价、注水方案的设计具有重要意义.%In order to describe the fractured reservoir dynamic characteristics of injection well more accurately and get more reliable information about formation and test wells,the interpretation model for pressure fall-off test of water injection well was presented and numerically solved by Bucklev-Leverrett saturation,and typical fitting chart was obtained.According to the characteristics of pressure fall-off curve,seven distinct flow phases can be divided:wellbore storage effect,skin effect,matrix crack channeling,water radial flow,response of oil-water,radial flow of total system,and boundary response phases.The viscosity difference between oil and water would lead to the upward of the double logarithmic curve.The model can be used for calculating the position of the injection front,aud analyzing the stratigraphic information and boundary conditions around the injection wells.The research results provide a practical reference for the dynamic evaluation and design of iujection wells.