Development characteristics and prediction of the fractures in thermal reservoir in Wumishan Formation, Yanling buried hill belt, Jizhong depression

The bedrock of Wumishan formation in Yanling buried hill belt of Jizhong Sag has high temperature, high heat, crack cave development, and great geothermal exploitation potential. Due to the control of multi-stage structure and karst, the reservoir space has various types and complex structures. Fractures are the main factors affecting heat carbonate reservoir development. Combining with the characteristics of regional tectonic evolution and stress, through the field outcrop, core, thin section, 3D seismic data analysis, fracture characteristics for the development of reservoir in the studied area is described, and that the region is mainly the large angle of the development structure cracks and dissolved fracture, along the seam with solution pores. Since fracture development is mainly affected by tectonic stress factors, the multi-angle fusion technology of seismic attributes such as coherence, curvature, texture and ant body is preferred to identify fracture network system in this study, and the distribution characteristics of three types of structural fracture development zones are summarized. As a result of the buried hill fracture development degree of karst has control effect, combined with Jizhong depression exposure period unconformity karst development characteristics of karst, recognize the distribution of karst development focused on the tectonic fault zone and buried hill near the top surface weathering crust, and validated by karst properties prediction profile and production well, drilling mud leak rate alignment is higher. It is further shown that the mud loss site is mainly the development location of dissolution pores. Finally, the eastern part of Yanling tectonic belt and the western part of Chuan tectonic belt are the most favorable reservoir development areas.