Development status and suggestions of hot dry rock hydraulic fracturing for building geothermal reservoirs

Abstract

Energy is a powerful guarantee for the long-term stable development of the economy and society. At the same time, China has also entered a critical period of ecological civilization construction. To achieve this goal, it is urgent to build a clean, low-carbon, efficient, and diversified modern energy system. As new environment-friendly energy, hot dry rock (HDR) is expected to promote the energy mix transition. The development of HDR requires the establishment of an enhanced geothermal system(EGS). It is to build an well circulation to extract thermal energy for power generation after drilling and hydraulic fracturing. Since the 1970s, many developed countries have tried to develop HDR successively. However, limited by key technologies, such as artificial heat storage construction and induced earthquake prevention, few EGS projects have been successfully operated. In recent years, as the advantages and the large-scale development feasibility of HDR are gradually recognized by the international society, the number of EGS is increasing generally. Hydraulic fracturing is one of the core technologies to build the geothermal reservoir, which directly determines the heat transfer volume and the heat transfer efficiency. Based on the analysis of typical EGS cases at home and abroad, the characteristics of HDR hydraulic fracturing are summarized. Moreover, combined with several popular theoretical models and the actual situation of the first EGS (Qiabuqia HDR) in China, the relationship between the HDR fracturing and the induced earthquake is briefly described. From the point of view of fracturing technology, intelligent development, and micro-seismic moment tensor inversion, the suggestions for further development of HDR fracturing are presented.

Keywords

• hot dry rock
• hydraulic fracturing
• enhanced geothermal system
• human-induced earthquake
• gonghe basin