低渗透双重介质垂直裂缝井产能分析

DELIVERABILITY ANALYSIS OF VERTICAL FRACTURE WELLS IN LOW PERMEABILITY DUAL POROSITY RESERVOIR

针对低渗透双重介质地层进行水力压裂后形成的有限导流垂直裂缝,结合沃伦-鲁特模型,利用质量守恒和椭圆流法建立了低渗透双重介质油藏椭圆流数学模型,并应用拉普拉斯变换,求得了低渗透双重介质有限导流垂直裂缝井无因次产量表达式。运用Stefest数值反演,绘制了无因次产量随时间变化的双对数特征曲线图,对影响低渗透双重介质油藏有限导流垂直裂缝井井底压力动态的诸多影响因素进行了分析。分析结果表明,随着生产时间推移,启动压力梯度对产能影响越来越显著。

According to finite conductivity vertical fractures derived from hydraulic fractured in low permeability dual porosity reservoir,based on the Warant-Root model in dual Porosity,elliptical flow model of finite conductivity fracture in low permeability dual porosity reservoir is built by using mass conservation equation and elliptical flow method.Furthermore,based on the model,through Laplace Transform,the formula of dimensionless rate in Laplace Space to finite conductivity vertical fracture model in dual porosity reservoir can be obtained.By using Stefest Numerical Inversion of Laplace Transform,the type curves of dimensionless rate change as time can be drawn and the dynamic and influence factors can be discussed.It is shown that the effect of threshold pressure gradient on dimensionless rate will increase as time goes.