| Geothermal,as an environmentally friendly energy source,has become an important direction for China to adjust the energy structure,improve the ecological environment and promote economic development by increasing its exploration and development.The geothermal resources in the Moxi fault zone are very abundant,and the surface heat display type is mainly hot springs and geothermal wells,but there are great prospects for the development and utilization of geothermal resources.In this paper,the geothermal resources of the Moxi fault zone are selected as the research object,and on the basis of field geological investigation,the surface temperature field,geothermal anomalies and geological structure distribution characteristics and their relationships are analyzed in the area;the water-rock interaction process and the factors affecting the chemical characteristics of geothermal water in the process of underground hot water circulation are studied by using hydrogeochemical characteristics analysis;the four elements of regional heat source,water source,storage cover and channel are summarized,and the geothermal storage elements are revealed.The four elements of regional heat source,water source,storage cover and channel were summarized,and the geothermal resource genesis model and reservoir pattern in the study area were revealed;and the storage quantity and quality of geothermal water were evaluated.The following results were achieved:（1）To a certain degree,the Moxi fault zone controls the topographic and geomorphological features of the study area and the development of the fault system of the fault zone,which provides good geological conditions for the formation and distribution of geothermal resources;the discovered geological hot spots in the study area are mainly distributed at the intersection of fractures,folds and fractures tangent positions.（2）The temperature field of the surface of the Moxi fault zone shows certain regularity and complexity in space.There are many geothermal abnormalities around the fractures and they are mostly distributed along the fracture direction in a belt-like pattern,forming a large area of geothermal anomalies in the densely developed fracture area.Geothermal anomalies have a good indication for geothermal anomalies.The following geothermal prospective areas are initially delineated according to geothermal anomalies:Moxi Hailuogou geothermal anomaly area,Tianwan Caoke geothermal anomaly area,and geothermal anomaly area around northwest of Shimian.（3）The geochemical features of the geothermal water in the Moxi-Hailuogou area are significantly different from those of the geothermal water in the Caoke area.The geothermal water geochemistry in the Moxi-Hailuogou area is Na-（Ca）-HCO3,while that in the Caoke area is Na-（Ca）-HCO3and Na-（Ca）-HCO3-SO4;the geothermal water geochemistry in the Moxi-Hailuogou area is mainly influenced by the dissolution of silicate rock minerals,while that in the Caoke area is mainly influenced by the mineral dissolution of silicate minerals and carbonate rock minerals,and the geothermal water in the Caoke area is more influenced by the dissolution of evaporite rock than that in the Caoke area.The geothermal water in the area is more influenced by the dissolution of evaporite than that in the area of Moxi-Hailuogou,and there is a strong effect of cation exchange between the geothermal water and the surrounding rocks in both areas.（4）The geothermal system genesis model in the research area can be summarized as follows:ice and snow melt water and atmospheric precipitation from the high-altitude snow mountains in the west side of the area move from west to east under the high head pressure formed in the high mountain canyon topography and seep down along the fracture rift system.In the process of deep circulation,surface water and groundwater form hot water under the action of deep heat flow conduction in the middle and lower crustal part of the melt,and the hot water moves upward along the fracture gap system under the action of pressure,mainly between secondary fractures,secondary fractures and the main fracture intersection and fractures and folds tangent position to form a number of geothermal anomalies,in which the fracture gap system has a high degree of development and good continuity of geothermal anomalies have more Hot springs are exposed.The study area is a medium to high temperature geothermal system with metamorphic carbonate rocks as thermal reservoirs,with thermal storage temperatures ranging from 61.3℃to 229℃,a maximum circulation depth of about 4.359 km,and a recharge height of 1390.92 m to4179.27 m.Geothermal water has water-rock interaction with a variety of minerals in the surrounding rocks during deep circulation,some hot springs have the addition of deep material,and the hot water reaches the shallow part and mixes with the shallow cold water and comes out of the ground,most of the hot water is in an unbalanced state and shows different hydrochemical characteristics.（5）The distribution of geothermal resources in the study area is mainly influenced by factors such as reservoir cover,geological structure,hydrodynamic conditions and heat source,etc.The combination of regional stratigraphic lithology,hydrodynamic conditions and geological structures derived from large fractures into a spatial allocation plays a decisive role in the distribution of geothermal resources.（6）The geothermal resources in the study area have a large potential for development and excellent water quality,which can be developed and utilized as medical thermal mineral water and industrial water.The research results will be applied to geothermal exploration work,and geothermal anomaly target areas will be circled,and geothermal water with a stable temperature of 45℃and a stable flow rate of 51.07 m3/h will be obtained by drilling wells. |
