| Ruidian geothermal field is located in the interchange between Tengchong-Lianghe arc-shaped thermal activity fault zone and the Ruidian-Qushi fault zone,which is one of the strongest hot fields in Tengchong geothermal heat.The predecessor has made detailed research on hydro geological survey,drill and geophysical exploration in Ruidian geothermal field,and has gained certain results.In this paper,based on Ruidian geothermal field as the research object,by its unique tectonic movement,magmatic activities and high geothermal anomaly area are studied in this paper.This paper analyses and studies the heat source-dominated heat storage model of magmatic chamber in Ruidian geothermal field of Tengchong County by the methods of multidisciplinary information integration,numerical simulation and comparative geology.Based on the research data of geology,geophysics and fluid chemistry of Ruidian and adjacent areas,a detailed field geological survey,sample collection and laboratory test are carried out in the study area.According to the integration and summarization of previous data,this paper focuses on the following study aspects:a,Study the evolutionary characteristics of regional geological tectonic background,and the relationship between regional magmatic chamber invasion and tectonic activity and the geothermal anomaly zone;b,Study the physic-chemical analysis,geological structure and thermal field thermal storage structure in the study area;c,Based on characteristics of chemical composition of fluid in Ruidian geothermal field,H-O isotopic characteristics and analysis of lithofacies characteristics of basal granite,the cause of the difference in fluid chemical composition are studied,and the age of hot fluid supply and the age of hot fluid are analysed and deduced;d,Using the method of AquaChem analysis combined with CL-SO4-HCO3 triangular figure,Na-K-Mg triangular map,Piper diagram,Langelier-Ludwig diagram,Ternary diagram and Schoeller Plot fingerprints,the combinatorial characteristics and evolution of the hot fluid chemistry of Ruidian geothermal field have been studied;e,Analyse the hydrothermal mineral saturation index of hot springs and thermal fluid equilibrium of hot water in the study area through PHREEQC software;f,Analyse the ratio of shallow and deep heat storage and the ratio of"cold" and hot fluid by means of quartz temperature scale,silicon enthalpy diagram method,chlorine enthalpy diagram method and fluid chemical linear regression;g,Study the two-dimensional and three-dimensional temperature field response models of the geothermal field in the study area simulated by magma chamber through ANSYS simulation software;h,The coupling mechanism of the geothermal field is analysed by FEFLOW simulation software,comprehensive geothermal distribution characteristics,heat storage temperature,hot fluid circulation basin,hot fluid age and fluid migration model;i,Based on the above research results,the genetic model of the heat storage of the magma chamber in Ruidian geothermal field is established.The paper has made the following achievements and knowledge:(1)The DaYingjiang-Tengchong fault zone in the study area is the main body of the hot-field thermal control structure,which can be turned to the Gudong-Mazhan magma chamber and provide high temperature heat source condition for the formation of Ruidian high temperature geothermal field.The Ruidian-Qushi fault is also a large secondary thermal fault structure.(2)The base of Ruidian geothermal field is the biotite granite,which is the product of Yanshan late magmatic activity.The alteration of its surrounding rock is strong,mainly potassium long petrochemical,sodium petrifaction,cloud meteorite,secondary alteration of pyrite mineralization,chlorite and carbonation.The granite in the study area is rich in radioactive elements such as 238U,232Th and 40K,and the average heat generation rate in the enrichment layer is 6.90?W/m3.(3)The lithologic and structural faults in the study area as well as the geothermal geologic conditions in the thermal field are the main factors controlling the spatial differences in fluid chemical composition.Combined with the study of the equilibrium of the fluid chemistry phase,the mineral resources such as potassium feldspar,albite,sodium mica and biotite required for the dissolution of the hot fluid are basically consistent with the composition of the granite mineral elements in the study area.The fluid component is mainly controlled by the dissolution of the rock by the hot fluid,the alteration of the magma,the hydrothermal,and the groundwater recharge.(4)The correlation between Cl and the characteristic components Na,F,B,Li,Rb,Cs and SiO2 in the geothermal fluid is good,indicating that the thermal water source is uniform and the mixed process of hot and cold fluid is single,which can deduce the primary maternal fluid is mixed with the same deep heat reservoir.The hydrothermal chemical types of the Ruidian geothermal field are mainly HCO3·Cl-Na,followed by HC03 F-Na.(5)Using the hydrogen and oxygen isotopic characteristics of the geothermal field,the atmospheric precipitation of the recharge heat storage is mainly from the east and south of the middle and high mountain areas above 2200m.Tritium dating to calculate the temperature of the mixed heat fluid in the Ruidian geothermal field is greater than 15 years.By using the Quartz isothermal scale method,silicon-chlorine enthalpy diagram show that the shallow heat storage is about 140? and the deep heat storage is about 220?.The results show that there are "cold",hot fluid mixing process,and mixing ratio of hot and "cold" water is generally between 60%and 70%.(6)Based on the thermal reservoir structure of Ruidian geothermal field,this paper presents the conceptual model of Ruidian thermal storage.Geothermal field heat storage can be divided into granite weathering zone deep heat storage and under the new system of sand and gravel layer shallow heat storage two layers.(7)Through the use of AN SYS finite element simulation software,the characteristics of the temperature field in the study area after inversion of the simulated magma capsule have been studied.The influence of the late Pleistocene magma chamber on the field temperature field is significant,which is the main heat source of the formation of Ruidian high temperature geothermal field.(8)In this paper,based on the geothermal geologic conditions of thermal field,the chemical composition,chemical combination type and its origin and the quantitative analysis of the mixed model,the chemical field of thermal field has been established.According to the background of the geothermal field,the thermal storage structure,the geothermal gradient characteristics,the geothermal heat flow characteristics,the magmatic chamber invasion and the regional geothermal field,the numerical model of regional geothermal field has been established.In the above research process,the geothermal characteristics,the thermal storage temperature,the hot fluid circulation basin,the hot fluid age and the fluid migration mode are studied,and the FEFLOW simulation software is used to study the genetic model of the Ruidian geothermal field,which provides the quantitative support to explore the cause of the Ruidian geothermal field. |
PDF Full Text Request