水力压裂过程中,支撑剂在裂缝内的运移和铺置情况对油田产能具有重要影响。前人的研究大多没有考虑流体滤失对支撑剂在裂缝中的影响。本文基于Cross本构方程和Eular-granular多相流模型,在考虑了裂缝壁面流体滤失的情况下,对裂缝内的携砂流动进行了数值模拟,并且采用自主设计的裂缝试验装置对模型进行实验验证。结果表明,对于Cross流体,随着壁面滤失速率的提高,裂缝内支撑剂体积分数逐渐降低,砂堤高度同时降低。采用低砂比、低密度、小粒径的支撑剂有利于裂缝内携砂平衡高度的降低,有利于延长入口与支撑剂平衡高度之间的铺置距离,减小砂堵风险,支撑剂铺置更靠近裂缝远端。

The transport and placement of proppant within fractures in the process of hydraulic fracturing significantly impact oilfield productivity. Many previous studies have overlooked the influence of fluid filtration loss on proppant behavior within fractures. In this study, by using the Cross constitutive equation and the Eulerian-granular multiphase flow model, we conducted numerical simulations of sand-carrying flow within fractures with considering fluid filtration loss along the fracture wall. The model was experimentally validated using a custom-designed fracture test facility. The results indicate that, for Cross fluid, an increase in wall filtration loss rate leads to a gradual reduction in the volume fraction of proppant within the fracture, accompanied by a decrease in sand bank height although the overall difference is small. The utilization of proppant with a low sand ratio, low density, and small particle size proves advantageous in reducing the sand-carrying equilibrium height within the fracture. This, in turn, contributes to extending the spreading distance between the inlet and the proppant equilibrium height, thereby reducing the risk of sand plugging and enhancing the sand-carrying capacity of the fracturing fluid.

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