各向异性天然裂缝油藏裂缝方位的确定

在天然裂缝油藏中，裂缝的主方向决定了主渗透率的方向，确定裂缝方位对于天然裂缝油藏开发和注水方案的设计具有重要的意义。基于Ｗａｒｅｎ和Ｒｏｏｔ提出的双孔隙度模型建立了各向异性天然裂缝油藏的数学模型，通过坐标变换和Ｌａｐｌａｃｅ变换，求出了该模型在Ｌａｐｌａｃｅ空间的分析解，用Ｓｔｅｆｅｓｔ数值反演方法求出该模型在实空间的解。同时给出了用最小二乘法对多井干扰试井的压力数据拟合确定裂缝方位的方法。

DETERMINATION OF ORIENTATION OF THE FRACTURES IN AN ANISOTROPIC NATURALLY FRACTURED RESERVOIR

The principal direction of the fracture can be used to determine the direction of principal permeability in a nature fracture reservoir. Determination of fracture orientation is very important for the design of reservoir development and waterflooding. This paper presents a mathematical model based on the double porosity model proposed by Warren and Root for an anisotropic naturally fractured reservoir. The analytical solution in Laplace space is obtained by coordinate transform and Laplace transform. The solution of the model in real space is calculated by the use of Stefest Laplace inversion transform. Depending on the result, a method is presented to determine the fracture orientation by fitting the pressure data from multiple well interference testing with least square method.