Study On The Control of Tectonic Evolution On Karst Geothermal Reservoirs of Jixian System In Niutuozhen Geothermal Field, China

Niutuozhen Geothermal Field is one of the most famous geothermal fields in Xiongan New Area, and its karst geothermal reservoirs have unique geothermal resource endowment and development conditions. Based on the measured data of geophysical exploration, deep geothermal drilling, well logging, and so on, the present tectonic morphology of the geothermal field and the karst geothermal reservoirs spatial distribution are further defined, which is that the Jixian System carbonate buried hill internal structure is generally characterized by high in the south and low in the north, high in the east and low in the west, and the high point is located in the south of the uplift and gradually sinks to the northeast. Based on the typical profile analysis of Langgu sag, Niutuozhen uplift and Baxian sag, this paper describes three sedimentary and tectonic evolution stages of the geothermal field, which are neoproterozoic to Mesozoic reservoir development and formation stage, Paleogene uplift development and Neogene to Quaternary burial stage, and analyzes the control effect on the spatial distribution and physical properties of karst geothermal reservoirs in Jixian System by tectonic evolution. The controlling effect results in the development of karst fractures and dissolution pores within 150 meters below the unconformity surface of the weathering crust at the top, which become the most developed part of the geothermal reservoir. The Steady-state temperature logging and productivity test data of geothermal exploration wells show that, under the action of thermal convection, deep heat flow channels through the thermal and water control structures such as Daxing fault, Niudong fault and Rongcheng fault, and high permeability layers, affecting the temperature field of karst heat storage and overlying strata. In conclusion, due to the control of sedimentation and multi-stage tectonic evolution in the area, the accumulation characteristics of karst geothermal reservoirs resources of Jixian System in Niutuozhen Geothermal Field were finally formed.