Method for Visualizing Fractures Induced by Laboratory-Based Hydraulic Fracturing and Its Application to Shale Samples
Method for Visualizing Fractures Induced by Laboratory-Based Hydraulic Fracturing and Its Application to Shale Samples
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DOI：
10.3390/en11081976
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发表时间：
2018-07
期刊：
影响因子：
3.2
通讯作者：
Youqing Chen;M. Naoi;Yuto Tomonaga;Takashi Akai;Hiroyuki Tanaka;S. Takagi;T. Ishida
中科院分区：
文献类型：
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作者：
Youqing Chen;M. Naoi;Yuto Tomonaga;Takashi Akai;Hiroyuki Tanaka;S. Takagi;T. Ishida
更好地理解页岩油气藏中水力压裂增产的过程对于提高资源生产率是必要的。然而，直接观察包括诱导裂缝的水力刺激区域是困难的。在本研究中，我们开发了一种新的方法，直接可视化区域的页岩试样浸渍的流体在水力压裂。所提出的实验室方法使用与荧光物质混合的热固性树脂作为压裂液。破裂后，通过加热将树脂固定在样品内，然后在紫外光下观察切割部分。根据亮度，我们可以区分诱导裂缝及其周围的区域浸渍的流体从其他地区没有达到的流体。偏光显微镜观察清楚地揭示了微米尺度上曲折或分支裂缝的详细结构以及裂缝与组成矿物之间的相互作用。该实验观测方法有助于了解水力压裂增产过程及其与岩石微观特征的关系，对页岩油气资源开发中压裂设计优化具有重要意义。
A better understanding of the process of stimulation by hydraulic fracturing in shale gas and oil reservoirs is necessary for improving resource productivity. However, direct observation of hydraulically stimulated regions including induced fractures has been difficult. In the present study, we develop a new approach for directly visualizing regions of shale specimens impregnated by fluid during hydraulic fracturing. The proposed laboratory method uses a thermosetting resin mixed with a fluorescent substance as a fracturing fluid. After fracturing, the resin is fixed within the specimens by heating, and the cut sections are then observed under ultraviolet light. Based on brightness, we can then distinguish induced fractures and their surrounding regions impregnated by the fluid from other regions not reached by the fluid. Polarization microscope observation clearly reveals the detailed structures of tortuous or branched fractures on the micron scale and interactions between fractures and constituent minerals. The proposed experimental and observation method is useful for understanding the process of stimulation by hydraulic fracturing and its relationship with microscopic rock characteristics, which is important for fracturing design optimization in shale gas and oil resource development.