Geothermal System In Tangchi Area,Kunming City,Yunnan Province Characteristics And Causes

As a new type of energy,geothermal energy is one of the hot spots of energy utilization and development in the future.Strengthening the research of geothermal system is helpful to the exploitation and protection of geothermal resources.Tangchi geothermal field is located in the northeast of Yangzonghai and east of the west branch of Xiaojiang Fault.The terrain is high in the north and low in the south.The geothermal water is characterized by high temperature and rich in fluorine,metasilic acid and sulfur.Several nearly north-south and ne-trending faults converge here,which provides necessary conditions for the formation of Tangchi geothermal field.Tangchi geothermal field is rich in geothermal resources and has great development potential.The research on the characteristics of geothermal system and the genesis of geothermal water in Tangchi area will contribute to the rational development and utilization of geothermal resources in Tangchi area,and is of great significance to promote the development of regional social economy.Taking Tangchi area geothermal system as the research object,based on"kunming yangzonghai Tangchi area management committee of geothermal water resources survey project,through field investigation,field test and hydrology geochemistry,regional strata,tectonic geology analysis,numerical simulation results,focus on research from the following several aspects:background of the study area;The characteristics of hydrochemical composition,hydrogen and oxygen isotope,carbon isotope,helium isotope,distribution of hot fluid,recharge elevation of hot fluid,and source of special gases of geothermal fluid in Tangchi area are analyzed.Horizontal and vertical characteristics of geothermal field in the study area;Using FEFLOW to analyze the geothermal distribution characteristics;The characteristics of thermal convection model are coupled.The characteristics and causes of geothermal system in the region are studied in detail.The formation conditions,distribution characteristics and system characteristics of geothermal were determined,and the conceptual model of geothermal genesis in the research area was constructed.The specific research results are as follows:（1）Based on the isotopic characteristics of geothermal water,it shows that the groundwater recharge mainly comes from the rainfall infiltration recharge in the mountainous area around Tangchi,and the recharge altitude is 2363～2530 m.The phenomenon of oxygen drift inδ¹⁸O indicates that geothermal water has experienced a long period of underground runoff and retention.（2）According to the characteristics of horizontal geothermal and vertical geothermal,the ground temperature at the F1 fault zone is high,and the fault structure F1 is the main thermal conduction channel for the formation of geothermal resources in this area.According to the numerical simulation verification,the simulated geothermal field is consistent with the actual geothermal field,and the temperature near the F1 fault well is high.（3）Tangchi geothermal field belongs to the middle-low temperature geothermal field（Ⅱ-3）,and its heat storage type is stratified convection type geothermal field with complex geological structure conditions.The thermal reservoir type is carbonate rock dominated by dissolution fissures,pores and caves.