共和盆地当家寺岩体节理裂隙特征及对干热岩储层裂缝指示意义OA

Natural fractures in hot dry rock reservoir are of great significance for artificial reservoir construction and dry hot rock exploitation.Dangjiasi pluton in Gonghe Basin is demonstrated to be the same geological body as the explored high-temperature hot dry rock in this paper,after the analysis of regional structure,lithology and age.Besides,the development,occurrence characteristics and cutting relationship of the joints and fractures in Dangjiasi pluton were analyzed in detail based on 5 289 joints and fractures accumulated from 152 investigation points.And the fracture characteristics were compared with those of the hot dry rock borehole reservoir in the ex-ploitation site.The results show that the joints and fractures of Dangjiasi pluton were well-developed and mainly shear joints,and the dominant strike was NW and NE.The dip angles were mainly high,and those above 60° ac-counted for 64.2％.The most developed fractures were SE in dip and NE in strike,with dip angle greater than 60°.The fracture formation had multiple stages,which was mainly manifested as the NE strike joints and fractures cutting in the NE strike.The occurrence characteristics of joints and fissures formed by regional tectonic activities in Dangjiasi pluton were basically coupled with the fractures in hot dry rock reservoir,compared with fractures characteristics of hot dry rock.The overall dominant strike,dominant dip angle,and the occurrence of the most developed fractures were basically consistent.The results show that the occurrence of shallow structural joints and fractures of the same geologic body could provide surface basis for studying the occurrence of deep hot dry rock reservoir fractures.