Study Of Geothermal Reservoir Engineering In Low-middle Temperature

Study of low and middle temperature geothermal reservoir engineering is just start in China and it is very important in geothermal reservoir engineering. The geothermal reservoir research, where the heat come from, heat transfer condition and geothermal reservoir concept model of Tianjin geothermal field are studied in this dissertation. Mesozoic and Cenozoic basins are widespread large Mesozoic down-faulted basins. Foundation of the basin is made from Proterozoic erathem and Paleozoic erathem that are carbonate rock and clastic rock. For example Tianjin, Songliao,Jianghan,Subei,and Weihe basibs are very rich in low and middle temperature geothermal resources. The magma activity and volcano are not effect to geothermal field form and distribution.The reselt of geothermal exploration show that there are not high temperature geothermal field in this areas. The main case of the heat transfer is conduction in tianjin.There is another case is convection near some deep faults. Most geothermal systems are found in this basins are two-layer systems. The first geothermal reservoir is made from sedimentary rock or soft-sediment of Tertiary system.The second one is made from Proterozoic erathem and Paleozoic erathem that are carbonate rock and clastic rock. During the early stages of field development, simpler methods of assessment such as stored heat calculation decline curve analysis or lumped parameter models are useful. Distributed parameter model are used for geothermal field that the different parameter changed with time and space. Numerical modeling is often used for thises complex geothermal systems. It is important to realize that because the vast majority of the heat in geothermal reservoir is stored as the rock matrix, a program of reinjecting water is necessary to maximize the energy recovery. To be successful, the program must be designed to minimize the effects of injectivity decline and thermal interference.The carbonate rock and clastic rock of Proterozoic erathem and Paleozoic erathem and sedimentary rock or soft-sediment of Tertiary system geothermal reservoirs are main object in this dissertation.The 3D numerical model is used in this resource assessmen. The results show that the water level will be down to -106 to -180m in the same exploitation condition now. Reinjection will be decrease water level drow down. Base on the data of Wuqing area, the large discharge and less water drow down are the aim of geothermal exploitation. The results are very useful for managerment.