| Songpan-Ganzi area is rich in geothermal resources. Geothermal resources are cleanand renewable energies. They are either buried underground in the form of hot wateror water vapor or outcropped on surface. They can be widely used for power eneration,medical treatment and heating and they are new natural energies with great prospectonly after the coal, oil and natural gas. Songpan-Ganzi area is rich in geothermalresources. How to explore these resources effectively is not only a scientifical andtechnical problem, but also a economical problem. with the Songpan-Ganzi area asthe research area, with the geophysical effects of geotherm as the research object, thethesis aims to find the proper geophysical method to explore geothermal resourceseffectively in the research region.Starting with field investigation, combining previous research results, the thesisanalyzes the distribution of geothermal resources and formation mechanism insongpan ganzi area. Based on the type of geothermal heat, temperature controlstructure, geophysical methods, the geothermal songpan ganzi region can be dividedinto three subregion, including Ⅰ area of jinsha river fault zone and garze litangfracture zone control of low temperature geothermal resources in the area; Ⅱ areafor fresh water river fault zone controlled by low temperature geothermal resources inthe study area; Ⅲ area for barkam town north west fault zone, longmenshan northeast to fault zone and minshan mountains-serrated teeth-gun ridge fault zonecontrolled by low temperature geothermal resources in the study area. The thesisconcludes that thermal reservoir distribution is mainly controlled by tectonic belt orrock mass. and develops the heat transfer and thermal storage structure model in theresearch region.Geothermal is characterized by abnormal high temperature. TThis thesis studies the relationship between temperature and velocity, rock strength, rock resistivity,underground water solution salinity, magnetization strength, thermal conductivity andthe correlation between groundwater as well as geothermal water and apparentresistivity. With the increase of temperature, velocity, rock strength, electricalresistivity, magnetic strength and thermal conductivity decreases nonlinearly, whilethe intensity of magnetic field increases non-linearly. With the increase of rocksalinity, electricity, also increases nonlinearly. The study lays a profoundtheoretical foundation for the geothermal exploration in songpan ganzi area. It isbased on the54water resistivity data collected from fresh water river, wenchuanguanyin temple heat field and ganzi ZhuoDe thermal fields It lays down afoundation for the use of electromagnetic exploration to evaluate geothermalresources.Using the geothermal field in kangding yulin palace and yalla river shelter-forestas an example, we study how the geothermal group structure, the output location ofheat reservoir, hot water migration path shoule be taken into account in the choice ofexploration method. We mainly studies the electromagnetic exploration’s applicationin these two geothermal fields. A thorough analysis of the effectiveness of the methodis discussed in this paper.With the geology structure and exploration destination known, electric (magnetic)method is the most effective method of geothermal field exploration. For geothermalbody buried less than100meters, USES dc symmetrical quadrupole electric soundingor IP prospecting may be used; For heat storage bodies buried between100metersand500meters, high power excitation point method or a high frequencymagnetotelluric method exploration should be used; For heat storage body buried verydeep (greater than500meters), the controlled source audio-frequency magnetotelluricsounding is the best choice; In detecting reservoir buried deeper than2km, and ofcourse if time allows and site condition are good, the magnetotelluric sounding andaudio magnetotelluric sounding can be used for geothermal exploration,. In theinterpretation of electromagnetic prospecting data, attention should be paid to avoidserious deviation due to the influence of rock structure and pore fluid salinity onresistivity.The thesis summarizes the the geothermal distribution and efficient geophysicalprospecting method in the research area. It serves as a valuable database ofgeothermal exploration and development in this area and also provides importanteffective technical support. This paper’s innovation points are as follows:(1) based on the geophysical exploration, combining geothermal type andstructure of temperature control, the geothermal songpan ganzi region is divided intothree study areas, including Ⅰ area of jinsha river fault zone and garze litangfracture zone control of low temperature geothermal resources in the area; Ⅱ areafor fresh water river fault zone controlled by low temperature geothermal resources inthe study area; Ⅲ area for barkam town north west fault zone, longmenshan northeast to fault zone and minshan mountains-serrated teeth-gun ridge fault zonecontrolled by low temperature geothermal resources in the study area and is the focusof our research.(2) using the geophysical exploration results, puts forward the songpan ganziregion of the heat transfer model and thermal storage structure. Atmosphericprecipitation, including snow melt water, through the fault zone and fracture zone,infiltration near the heat source, through the exchange of heat storage to store layerprocess, and the last part of the overflow surface.(3) For the first time in the study area, the technology of using resistivity toestimate formation temperature is applied. We also pointed out that the technologyis strongly subjective to the mineralization of formation, rock resistivity of20℃ρ0and the impact of rock temperature coefficient(αvalues). But in songpan-ganziregion, this method works out effectively.(4) Based on the practice of geophysical methods in the area, the electromagneticmethod is proved to be the most effective method in geothermal exploration. A varietyof electromagnetic methods may be used to explore heat reseriors with differentdepths.. |
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