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低渗透缝洞型油藏低孔,低渗,裂缝,溶洞结构发育,形成基质,溶洞,裂缝三重介质孔隙结构系统,非达西因子的影响及裂缝分布的复杂性,使得对其渗流规律的研究比较困难。因此本文引入分形理论,建立考虑低速非达西效应的分形三重介质缝洞型油藏数学模型,通过Laplace变换及Stehfest数值反演的方法求出井底压力解,借助Matlab编程绘制压力动态曲线,划分渗流阶段,分析渗流规律,进行非线性参数敏感性分析,最后结合实际算例,验证模型正确性。结果表明,分形三重介质油藏渗流过程分为早期纯井储,过渡流,缝洞窜流,拟径向流,基质与溶洞、裂缝窜流,总体径向流6个渗流阶段;低速非达西效应对渗流规律的影响随时间的推移逐渐增大;启动压力梯度越大,总径向流阶段压力动态曲线上翘幅度越大;分形系数影响整个渗流过程,随着分形系数的增大,裂缝迂曲程度随之增大,致使渗流阻力增加,引起压力动态曲线整体上移幅度增大。
The low porosity, low permeability, fractures and cave structure of low-permeability fractured-cave reservoirs develop, and the formation of matrix, karst cave and fracture triple porosity system, the influence of non-Darcy factor and the complexity of fracture distribution make the seepage regularity Research is more difficult. Therefore, fractal theory is introduced in this paper to establish mathematical model of fractured-tricolor fractured-cavity reservoir considering low-speed non-Darcy effect. Pressure solution of bottom hole is obtained by Laplace transform and Stehfest numerical inversion method. Pressure dynamic curve is drawn by Matlab, Dividing the seepage stage, analyzing the seepage law and conducting nonlinear parameter sensitivity analysis. Finally, with the actual examples, the correctness of the model is verified. The results show that the seepage process of fractal triple-medium reservoir can be divided into six stages: early pure well reservoir, transitional flow, fractured channel flow, quasi-radial flow, matrix and cave, fracturing channeling and total radial flow. The effect of the west effect on the seepage law gradually increases with the passage of time. The larger the starting pressure gradient, the greater the up-stress amplitude of the dynamic pressure curve in the total radial flow stage. The fractal coefficient affects the whole seepage process. With the increase of the fractal coefficient, As the degree of tortuosity increases, the seepage resistance increases, causing the overall upward pressure dynamic curve to increase.