低渗两区复合油藏注水井试井解释模型

为了更加准确地描述注水开发的低渗透油藏动态特征,得到尽可能多的关于储层和测试井的可靠信息,建立了综合考虑井筒储存效应、表皮效应、启动压力梯度、渗透率非均质性等影响因素的低渗两区复合油藏注水井试井解释数学模型,应用贝塞尔函数和格林函数法求出井底压力的Laplace空间解,采用Stehfest数值反演算法得到实空间的解,并对模型的相关参数进行敏感性分析,绘制了井底压降、压力导数与时间的双对数关系曲线。结果表明,外区渗透率相对较低的复合油藏中,井储系数、内区渗透率、外区渗透率、内区半径是敏感因素;表皮因子和启动压力梯度不是敏感因素。

Well-test Interpretation Model for Water Injection Wells in Tow-regional Low Permeability Composite Reservoirs

In order to more precisely describe the behavioral characteristics of water flooded low permeability reservoirs,and obtain more dependable information about the reservoirs and the testing wells,a well test interpretation model was established for tow-regional low permeability composite reservoirs,which considered the factors of wellbore storage,skin effect,starting pressure gradient,permeability heterogeneity,and so on.Bassel Function and Green Function were deployed to gain bottom hole pressure in Laplace space.The method of Stehfest inversion was deployed to gain real space solution.The model parametric sensitivity was analyzed for drafting pressure drawdown and derivative curves.The research results indicate that wellbore storage,inside permeability and outside zone permeability,and interlayer radius are the sensitivity factors,but skin effect and starting pressure gradient are not.