通道压裂裂缝导流能力数值模拟研究

Numerical Simulation for Flow Conductivity in Channeling Fractures

为了计算通道压裂裂缝在实际条件下的导流能力并分析影响导流能力的因素,在分析通道压裂砂堤分布规律的基础上,建立了裂缝内流体流动模型,利用数值模拟方法模拟了某一通道压裂气井裂缝内流体的流动规律和压力分布规律,并计算了裂缝的导流能力。结果表明:通道压裂裂缝的导流能力基本不随井底流压、气体密度和气体黏度变化;通道压裂裂缝内空隙通道的结构和分布是影响裂缝导流能力的主要因素,如果通道压裂裂缝内没有形成连续的大通道或大通道坍缩形成离散分布的空隙结构,则裂缝内流体的流动阻力会增大,从而导致通道压裂裂缝导流能力较预期有大幅度降低。该研究结果可为提高通道压裂裂缝的导流能力提供理论依据。

To determine the conductivity of channeling fractures under field conditions and to identify factors that may affect such conductivity, a fluid flow model has been established in accordance with distribution of fractured sand bars. In addition, a numerical simulation has been performed to determine flow patterns of fluids in certain fracture and to calculate conductivity of such fractures. Research results showed that structures and distribution of pore channels in channeling fractures were key factors that might affect the conductivity of fractures. In the case that no continuous large channels were generated, or such major channels collapsed to generate dispersedly distributed pore structures, fluids in the fracture might encounter significant flow resistance. Under such circumstances, conductivities of channeling fractures might be reduced significantly. Relevant research results might provide a solid foundation to enhance conductivity of channeling fractures.