无限大双层越流油气藏井底压力的精确解

采用最大有效井径的概念，在考虑表皮效应和井筒储存影响的条件下，导出了一个具有层间越流的无限大双层越流油气藏井底压力的动态模型，通过拉氏变换，得到了拉氏空间下以Bessel函数表示的精确解。运用Crump数值反演方法，得到了实空间的解，分析了压力动态特征，计算结果表明：该模型不但适合于表皮系数为正的情况，也适合于表皮系数的为负的情形，而Burdet模型只适合于表皮系数为正的情况。由于解释模型参数集团化，更有利于绘制典型曲线，能够获得更加准确的地层参数。

Accurate Solution of Two-Layer Reservoir with Crossflow Including Wellbore Storage and Skin Effect

The maximum effective hole-diameter mathematical model describing flow of slightly compressible fluid through an infinite two-layer reservoir with corssflow is solved rigorously. The model considers all layers open to a single well in which the flow is at a constant total rate. The accurate solutions are expressed in terms of ordinary Bessel functions by using the method of Laplace transform. The numerical computation of these solutions is made by Crump numerical inversion method and the behavior of the system is studied as a function of various reservoir parameters. The new model is numerically stable when the skin is positive and negative,but Bourdet model is numerically stable only when the skin is positive. Because the curves explicitly include skin factor and other reservoir parameters, the techniques is expected to be more accurate than Bourdet model. The automatic history matching technique has made it possible to determine the individual layer properties and wellbore parameters accurately.