D罗辉双重低渗介质含启动压力梯度不定常渗流研究.docVIP

双重低渗介质含启动压力梯度不定常渗流研究 罗二辉1，王晓冬1，王建俊2 中国地质大学，北京 100083；2.中国石油大学，北京 102249) 基金项目：（国家科技重大专项2009ZX05009-004-03） 摘要：在双重低渗介质储层中建立了考虑启动压力梯度和动边界的交互作用影响的非达西不定常渗流模型；通过因变量变换新定义无量纲压力导数，从而线性化压力扩散方程，采用Laplace变换结合Stehfest数值反演算法求得井壁压力分布和动边界传播规律。通过对低渗双重介质中敏感参数(如启动压力梯度、弹性储容比、窜流系数等)分析表明：启动压力梯度对动边界传播规律、井壁压力及压力导数动态曲线有很大影响，启动压力梯度越大，动边界传播越慢、压力损失越大，并且井壁压力导数在后期有上翘特征。并运用Duhamel褶积建立了相应的现代试井分析典型曲线图版。 关键词：双重介质；启动压力梯度；动边界；低渗透；不定常渗流；非Darcy渗流 Study on the Fluid Transient Flow with Threshold Gradient in Dual-pore Low Permeability Porous Media LUO Er-hui1,WANG Xiao-dong1,WANG Jian-jun2 (1.China University of Geosciences, Beijing 100083,China；2.China University of Petroleum, Beijing 102249,China) （Important National Science Technology Specific Projects During the Eleventh Five-Year Plan Period: 2009ZX05009-004-03） Abstract: Taking threshold pressure gradient and moving boundary comprehensive effect into consideration, a Non-Darcy transient flow mathematic model in dual-pore low permeability media is set up. Pressure diffusion equation is linearized by new-defined dimensionless pressure derivative of dependent variable transformation. The solution of wellbore pressure and moving boundary propagation is solved with Laplace transform and Stehfest numerical reverse method, and the influence of sensitive parameters, such as threshold pressure gradient, storage ratio, inter porosity flow coefficient, is of great significance on moving boundary propagation, wellbore pressure and derivative type curve. It is shown that the greater threshold pressure gradient is, the slower the moving boundary runs, and the larger the pressure drops. As an effect of threshold pressure gradient and moving boundary, differential of wellbore pressure curve may be upwarp in the later stage of flow. Type curves for the modern well test analysis are obtained by means of Duhamel convolution theory. Keywords: dual-pore media, threshold pressure gradient, moving boundary, low permeability, transient flow, Non-Darcy flow 1 前言 大量研究表明，