Abstract：As a kind of green and renewable resources，the scale and efficient development of hot dry rock(HDR) geothermal energy has always been a worldwide research hotspot. In order to solve the problems of small heat exchange volume and poor heat exchange effect in the development of intact HDR geothermal by Enhanced Geothermal System(EGS)，the fracture distribution characteristics of natural deep HDR body were studied. Through field observation，it was found that structural fractures in deep granite bodies were universally filled by hydrothermal fluid or magma，forming fractured-subsequently-filled granite. Through micro-observation test，it is concluded that under the influence of high temperature action of backfill，changes in the number of thermal-cracking fractures of fractured-subsequently-filled granite versus the distance from the cementation interface can be divided into a zone in which the number of fractures fluctuates gently，a zone showing a sharp increase in the number of fractures，and a zone in which the fluctuation in the number of fractures decreases. The fractured-subsequently-filled granite mainly produces micro-fractures with length＞50 μm and length＞100 μm，and the position of the maximum number of thermal-cracking fractures with different length scales is located in the parent rock at a certain distance away from the cementation interface. When the fracture backfill thickness is 3.4cm，the unilateral influence range of the high temperature action of the fracture backfill is about 1 m. The widespread fracture backfill result in the formation of a huge weak-plane structure in the granite parent rock. Through hydraulic fracturing test，it is concluded that the weak-plane structure can be used as fracture channels to construct artificial reservoir through hydraulic fracturing，and can greatly reduce the breakdown pressure，so as to achieve large-scale and efficient construction of HDR artificial reservoirs. On this basis，the research on new technology of artificial reservoir construction in HDR geothermal exploitation constitutes a new research direction for HDR geothermal development.
阴伟涛. 裂缝后期充填花岗岩体裂缝分布特征研究[J]. 岩石力学与工程学报, 2023, 42(9): 2203-2211.
YIN Weitao. Experimental research on the fracture distribution characteristics of fractured-subsequently-filled granite. , 2023, 42(9): 2203-2211.
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2023, Vol. 42 
