Study On THM Multi Field Coupled Compressed Air Energy Storage In Aquifers Based On TOUGH-FLAC Integration

With the increasing consumption of fossil energy and environmental problems,people pay more attention to the development of renewable energy technology.However,there are some shortcomings in renewable energy technology: it cannot generate electricity continuously and stably.Directly connecting it to the power grid will increase the burden of the power grid and destroy the stability of the power grid.Therefore,large-scale energy storage technology has become an important part of renewable energy development.Compressed air energy storage,as the only two kind of 100 megawatt energy storage technologies,can not only meet the storage needs of renewable energy generation,but also have the advantages of pollution-free,high security and relatively low site selection requirements.Compressed air energy storage in aquifers,also known as CAESA,is a further development based on the technology of compressed air energy storage.It uses underground aquifers to replace the air tank in traditional compressed air energy storage system,using groundwater to provide pressure.It can further reduce the cost and reduce the site selection requirements of the power station.Based on the compressed air energy storage in aquifers,the model of underground aquifer gas storage was constructed by using TOUGH2 and FLAC3 D simulators in the thesis,analyzing the thermo-hydro-mechanical(THM)coupling model.According to the relevant parameters of Huntorf compressed air energy storage power station in Germany,a daily cycle CAESA system was designed.The results indicate that the inherent conditions of aquifers,such as permeability and geological structure,play decisive roles in CAESA.The over low permeability of aquifers makes the system unable to operate,while the over high permeability will reduce the energy efficiency;Among the three geological structures,anticline structure is the most favorable,it has the maximum cycle number and the minimum change of stress and displacement.Syncline structure is the worst condition.The formation of gas bubble by air injection will lead to the displacement of the upper and lower strata to both sides,and the stress accumulation of the upper and lower strata at the injection well location is the most serious.With the operation of the system,the stress in the aquifer gradually tends to the initial state,and the displacement of the top part recovers.However,the stress of the upper and lower strata changes very slowly,showing a lag state relative to the aquifer.There are totaly 62 figures,10 tables and 120 references in the thesis.