| Ma Long County is located between Kunming and Qujing. The paper infers that Ma Long County is rich in geothermal resources according to geological conditions and the 3 hot wells which are constructed successfully. Therefore, the geothermal research of Ma Long is of great significance to the exploitation and utilization of deep geothermal water. In this paper, the geothermal geological background and the hydrogeological conditions of the study area are systematically studied based on regional hydrological geological report, the field investigation of hydrogeological conditions and the surrounding areas of geothermal geology and the data of 3 geothermal wells. We also establish geothermal conceptual model and analyze geothermal formation mode from heat source, the source of geothermal water, heat reservoir and heat channel and cover. On this basis, the volume and hot water storage methods are adopted to calculate and evaluate thermal storage resources and geothermal water reserves of Ma Long County geothermal reservoir prospecting area in the study area, providing scientific basis for the development and utilization of geothermal resources. The main research contents and conclusions are as follows:1) Considering the geothermal resources exploitation utilization, thermal storage depth and heat storage temperature and structural conditions, the study erea will be divided into two areas of the old county and Ma Long geothermal reservoir prospective areas. The paper ascertains boundary conditions of Ma Long county geothermal reservoir prospective area, the area is 144km2. And according to the thermal reservoir buried depth, the geothermal reservoir area is divided shallow buried area, moderate burial area and deep burial area by h<1500m,1500<h<1800m and 1800<h<2500m.2) Through the analysis of the water quality reports of 5 water samples in the study area, we get that the geothermal water type is mainly HC03-Ca·Mg, with a small part is HCO3-Na·Ca. We calculate that the heat storage temperature of the study area is 55℃ to 65℃ according to the SiO2 content in water samples and the average geothermal gradient. In addition, there is a cold and hot water mixing function in the study area, and we get the hot and cold water mixing ratio is 55% to 60% and the temperature of the hot water before mixing is from 75.1℃ to 75.1℃.3) Geothermal system is stratified type which heat reservoir is dolomite of Dengying Formation of Sinian (Z2dn) in the study area. Deep heat flow transfers and heats reservoir continuously through faults and strata which is from the decay of radioactive elements and the upper mantle. And the overlying stratas are sandstone and shale of Cambrian Qiong Zhusi (∈1q) and Cang Langpu (∈1c), which are water and heat insulation. The dolomite of Sinian Dengying formation accepts atmospheric precipitation which is exposed on a large area on southeast of the old County and south of Ma Long County. To the deep migration, constantly absorbs the heat around the rock, and formating valuable geothermal water. The depth of geothermal water circulation reachs thermal reservoir bottom, the circulation depth of old County’s geothermal reservoir prospective area is 1553～1756 m, and the depth of Ma Long is 1921-2127 m.4) Geothermal resources and hot water storage amount are calculated by volume and storage method of Ma Long County geothermal reservoir prospecting area. Thermal storage resources is 1.21×1019J, converting into 4.13×108t of standard coal. Geothermal water storage is 2.84x109m3. Therefore, the study area is rich in geothermal resources and exploitation potential. |
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