Abstract The roughness of fractures may play an important role in affecting the migration and placement of proppants during hydraulic fracturing operations. A series of proppant flow experiments were conducted in attempt to compare the proppant transport mechanisms in rough fractures against those in smooth fractures. We examine the migration of proppants in rough and vertical fractures and then quantitatively reveal the effect of roughness on the instantaneous proppants transport and final proppants placement. The proppants-transport behavior in the rough and vertical fractures was observed to be totally different from that in the smooth and vertical fractures. The proppants in a rough vertical fracture do not progress like the regular sand bank that commonly occurs in the smooth fracture, but rather as an irregular-shape sand cluster with fractal characteristics. In the rough and vertical fracture, the phenomenon of proppants bridging is visually observed. The roughness of the fracture model not only affects how much of the fracture area is being occupied by the proppants, but also affects how tightly the proppants fill up the fracture.

中文翻译：

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粗糙垂直裂缝中支撑剂输运的可视化实验研究

摘要 水力压裂作业中，裂缝的粗糙度可能对支撑剂的运移和放置产生重要影响。进行了一系列支撑剂流动实验，试图将粗糙裂缝中的支撑剂输送机制与光滑裂缝中的支撑剂输送机制进行比较。我们检查了支撑剂在粗糙和垂直裂缝中的迁移，然后定量揭示了粗糙度对支撑剂瞬时传输和最终支撑剂放置的影响。观察到粗糙和垂直裂缝中的支撑剂输运行为与光滑和垂直裂缝中的完全不同。粗糙垂直裂缝中的支撑剂不像光滑裂缝中常见的规则砂堤那样前进，而是作为具有分形特征的不规则形状的沙簇。在粗糙和垂直的裂缝中，目视观察支撑剂架桥的现象。裂缝模型的粗糙度不仅影响有多少裂缝区域被支撑剂占据，而且影响支撑剂填充裂缝的紧密程度。