The Asian Geothermal Map And The Evaluation On Geothermal Potential

At present, the energy crisis and the environment pollution are two major problems which the humanity faces. As a member in the family of renewable energy source, the geothermal energy has great advantage than biological energy, wind energy, tidal power and so on. It is the practical energy source, also the enormous potential energy source. The total heat emitted by the earth to the ground is very large, but also very dispersive, and the energy used direct is quite limit. The production of geothermal has consanguineous internal relation to the happen, development, evolvement of lithosphere plate and the concomitant thermal situation, thermal history of the crust, especially, has direct relation to the tectonic stress field and thermal dynamic field. Therefore, it is very significant to understand producing principle of the geothermal source intensively, analyze every factors working on production and utilizing of the geothermal source, at last, and evaluate the geothermal potential of one area.As the largest continent, the Asia has abundant geothermal source. The paper did researches on distribution of Asian geothermal resource based on following projects:The National Natural Science Fund "The research on THCB coupled transport mechanism of water source heat pump" (NO.40972172), The Project-sponsored by Science and Technology Commission of Shanghai Municipality (10dz1202300), The science and technology innovation item of overseas student in Jilin province, The Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry and China Geological Survey "The mapping of Aisan underground water resource and environmental geology". The paper discussed from five parts:the database of the Asian geothermal, the map of the Asia geothermal, the distribution of the Asia geothermal, the establishment of the evaluation model about the geothermal potential based on BP network and the model application.Part 1:The specific task was to collect and collate the Asian hotspot data (including volcano, hot spring, and hot well). At the same time, the Asian terrestrial heat flow and geothermal gradient values in some areas were also collected. The last harvest was the database of the Asian geothermal.Part 2:Based on above data, draw the map of the Asia geothermal source by MapGIS. Meantime, accomplish the map of ground temperature field in 3000 meters and the outline map of geothermal gradient. The factors influencing the distribution of ground temperature, the relation during terrestrial heat flow and geological environment were analyzed; the rough distribution of the Asian ground temperature and geothermal gradient were summed up.Part 3:According to the geology types of the geothermal source's production and the occurrence properties, the Asian geothermal area was divided into three types, the modern volcano geothermal area, the crown failure geothermal area and the sedimentary basin geothermal area. The distribution of every type in Asian was analyzed and studied thoroughly, which further promoted the knowledge for production of geothermal source.Part 4:On the premise that there was large advantage to apply BP network for representing the non-linear relation during several factors. The BP network was imported to evaluate the geothermal potential in modern volcano geothermal area and sedimentary basin geothermal area. The all qualitative and quantitative factors influencing geothermal production and utilization in modern volcano geothermal area and sedimentary basin geothermal area were analyzed synthetically, than the main factors were chosen to be import of BP network model. The factors chosen in modern volcano geothermal area were:stratum layer and rock character, structure feature, volcano movement, hot display in ground surface, hydrochemistry feature, earthquake movement, geothermal gradient and hot spring temperature; chosen in sedimentary basin geothermal area were:stratum layer and rock character, structure feature, hydrodynamic condition, hydrochemistry feature, hot display in ground surface, geothermal gradient, terrestrial heat flow and information of hot well(drill)(that is exit temperature and flow of hot well in 1000m depth).The export was the geothermal potential. Therefore, the evaluation model of the geothermal potential was established based on BP network.Part 5:The geothermal potential in some areas was evaluated applying the models established in Part 4.The distribution map of Asian geothermal resource, the map of Asian temperature field in 3000m and the map of Asian geothermal gradient in the paper have gotten acceptance by the institute of Hydrogeology and Environmental Geology, CGS. They will have momentous current significance to know the formation and distribution of Asian geothermal source. The Matlab NNtool was applied fully to establish the evaluation model of geothermal potential based on BP network. During actual applications, many progresses were made. The combination of evaluation system and ANNs aimed to explore a new method to evaluate the geothermal potential.