变形三重介质低渗透油藏垂直裂缝井的非线性流动分析

The Non-Linear Flow Analysis of Finite Conductivity Vertically Fractured Wells in the Low Permeability Reservoir with Deformed Triple Porosity Medium

不仅考虑低渗透油藏具有启动压力梯度的渗流特征,还考虑应力敏感地层中介质的变形;发展了Cinco-Ley H.提出的有限导流垂直裂缝井双线性流理论,将流体在垂直裂缝与地层中形成的流动划分为两个区域—垂直裂缝中的线性流区域和变形三重介质低渗透油藏中的非线性流区域;由此建立了变形三重介质低渗透油藏有限导流垂直裂缝井的非线性流动模型。鉴于该模型的强非线性,采用稳定的有限差分格式求得其数值解,并将数值结果绘制成试井样板曲线。将数值结果与以往模型进行对比验证了本文模型研究的必要性。另外,还讨论了垂直裂缝井无因次导流能力、无因次启动压力梯度、变形系数、三重介质参数、井筒储集系数对无因次井底压力及压力导数的敏感性影响。

The flow characteristic that there existed a start-up pressure gradient in the low permeability reservoir and the deformation of the medium in the stress-sensitive formation were both considered.Developing Cinco-Ley H.＇s bilinear flow theory of finite conductivity vertically fractured wells,the fluid flow in the vertical fracture and formation was divided into two regions-the linear flow region in the vertical fracture and the non-linear flow region in the low permeability reservoir with deformed triple-porosity medium.As a result,the non-linear flow model of finite conductivity vertically fractured wells in the low permeability reservoir with deformed triple porosity medium was constructed.Due to the model＇s strong nonlinearity,stable finite difference schemes were adopted to obtain its numerical values.Typical west test curves were plotted by using these numerical results.Comparison of the numerical results with previous model verifies the research necessity of the proposed model in this paper.Besides,the sensitive effects of dimensionless conductivity of vertically fractured wells,dimensionless start-up pressure gradient,deformation factor,parameters of triple-porosity medium and coefficients of wellbore storage towards the dimensionless wellbore pressure and its derivative were discussed.