双渗四重介质压力动态分析

Analysis of dynamic pressure for the dual-permeability quadruple-media reservoirs

针对碳酸盐岩油藏复杂储层特征,建立大裂缝、微裂缝、溶蚀孔洞和基岩双渗四重介质数学模型。采用Laplace变换和特征参数分析法对模型进行求解,得到Laplace空间的解。采用Stehfest方法对Laplace空间解进行数值反演得到实空间的井底压力。分析表明:双渗四重介质中井底压力导数曲线出现了三个"凹子","凹子"的数量与大小主要由介质间的窜流系数、弹性储容比以及渗透率比共同来决定,这些参数的取值对压力导数曲线形态的影响较为敏感。含有微裂缝和大裂缝双渗的缝洞型模型更适合复杂碳酸盐岩储层的试井解释。

The mathematical model of the dual-permeability quadruple-media with largescale fractures,micro-fractures,vugs and matrix was established for the complex reservoir characteristics of the carbonate oil reservoirs.The Laplace transformation and characteristic parameter analysis were used to solve the model,and the solution of the Laplace space was obtained.To get the bottom hole pressure in the real space,the Stehfest method was used to inverse the Laplace space solution.The result showed that three concaves tended to be pre-sent in the pressure derivative curve of the dual-permeability quardrule-media reservoir,and the number and size of concaves were mainly determined the crossflow coefficient of the media,storativity ratio of the media and the permeability ratio,and the value of these pa-rameters were more sensitive to the influence of the shape of the pressure derivative curve.It was more suitable for the well test interpretation of complex carbonate reservoirs with the dual-permeability model of the large-scale fractures and the micro-fractures.