双重介质有限导流垂直裂缝井压力动态分析

Analysis of Pressure Behavior of Well in Double-Porosity Reservoir with Finite Conductivity Vertical Fractures

低渗透双重介质地层压裂后可形成有限导流垂直裂缝。结合沃伦-鲁特模型,利用质量守恒和椭圆流法建立了双重介质油藏椭圆流新模型,求得在拉普拉斯空间的井底压力表达式,并对井底压力动态的主要影响因素进行了分析。研究表明,其压力动态最显著的影响因素是井筒储集系数、裂缝表皮系数和无因次导流能力,井筒储集系数还极大地影响基岩向裂缝窜流出现的时间,并对碳酸盐岩油藏一口垂直裂缝井进行了实例解释。

The well with finite conductivity vertical fractures would be formed after fracturing in double-porosity reservoir. Based on the Warren-Root model, the mathematical model for well with finite conductivity vertical fractures in double-porosity reservoir is developed using mass conservation law and elliptical flow method. The equation for bottom-hole pressure of vertical fractured well is obtained using Laplace transform, and the main affecting factors to the bottom-hole pressure behavior are analyzed. The results indicates that wellbore storage factor, skin factor and fracture conductivity are the most obvious affecting factors to it, and the time of interporosity flow from matrix to natural fracture is affected strikingly by wellbore storage factor. Also, the buildup test result from a vertical fractured well in carbonate reservoir is .explained.