| The historical data of exploitation and recharge shows that when injection on geothermal exploration wells, the recharge amount of water and temperature equal to or greater than the exploitation of geothermal water. The average temperature of the exploitation of geothermal water is over 90℃. It shows that, the geothermal resources is used unreasonably and wasted. How to achieve sustainable use of geothermal resources is an urgent problem. This study selects TOUGH2.0 software to simulate the recharge on the study area, researches the trends of thermal reservoir temperature and pressure field under different exploitation and recharge conditions, and optimizes the exploration-reinjection plans finally.In Dongli District, the study area lies in the north basin off depression, of which the bedrock is mainly limestone and dolomite carbonate. The geothermal reservoir is mainly Cambrian, Ordovician and Jixian System Wumishan; Jixian System and mist mountain mining group is a major geothermal water layer onresearch area. In the analysis of geological structure background,and geothermal formation mechanism on the basis of heat, water, heat storage, cap and control heat storage structure and other geothermal geological conditions study,we focused on the Jixian System Wumishan heat reservoir geological conditions of geothermal heat storage characteristics, thermal storage conditions and temperature field, based on which the establishment the geothermal geological model. By analyzing the lithology of the study area heat storage layer, geothermal geological conditions and heat, water and sinks to determine the model range and strong currents, thermal boundary conditions; combining hydrogeological parameter, Wumishan geothermal well data and permeability, rock specific heat storage and other parameters of the geothermal reservoir generalized hierarchical, establish conceptual model. Finally, we according to the water temperature and the head data to determine the simulation time, the space division, and processing parameters division. Depending on the platform TOUGH2.0 to establish the temperature area Numerical model in Wumishan thermal energy storage—the simulation time is 2009.11-2015.11.The simulation area is about 460km2 which is focused on mining Irrigation located in the middle ground.At the same time, we combine the bed rock flow、temperature field、and data of DL48、DL51, and use the test estimate—correction method to rectify the geothermal geological parameters and optimize the parameters of the studyBased on present situation of exploitation,we design and optimize the two plans in reducing the amount of recharge water temperature and the recharge quantity of single well. The production wells is still current exploitation in Plan A. Recharge water temperature is 45 ℃.The well is mining all year around,and only recharging in warm period.Recharging flow is equal to mining flowannual in each well.In plan B,the production wells is still current. The recharging flow reduces to the fifty percent of the mining flow. Recharge water temperature is 45 ℃. The well is mining all year around,and only recharging in warm period.Model predictions show that within 20 years, the flow and temperature fields in the study area was less affected in the two plans. The net exploitation quantity of heat in plan A is 2.75 × 109 KJ, in plan B it is 3.01 × 109 KJ. Geothermal reserve method determined in Wumishan exploitable geothermal resource is 2.82 × 1015 KJ.In quantity of resource,the two plans both can realize a long-term exploitation safely.However in saving water and reasonable geothermal resources, PlanB can cut down 137×104m3 water recharge,and exploit 137×104m3, 2.52×108KJ quantity of heat. From the above, the Plan B is more reasonable than Plan A. |
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