Research On Heat Transfer Of Hot Dry Rock Fracture Storage Layer

With economic developing rapidly,energy consumption continues growing,followed the increasingly serious environmental problems.The renewable resources features that has a wide distribution with the lowest environmental impact and can be used in sustainable has drawn more and more people's attention.Especially with the introduction of the "Hot dry rock exploration and development demonstration plan of China" has promoted the process of dry hot rock theoretical research and practical study of the technology.Program requires that in the end of 2015,master the distribution of hot dry rock resources and reserves characteristic feature.At 2020,we will evaluate the national hot dry rock geothermal resource potential,delineated the development and utilization of target.It can be achieved the application of hot dry rock after 2020.In the northern Qinghai basin has identified as hot dry rock development target in 2011.It was found hot dry rock in the temperature of 168? in June 25,2014,which is the first time that discovered hot dry rock geothermal resources in China.The main purpose of hot dry rock geothermal resources evaluation is to determine its reserves characteristics.According to the current research on hot dry rock geothermal resource in China.Classifying hot dry rock geothermal resources.From site selection,distribution characteristics,temperature characteristics,parameters characteristics analysis characteristics of hot dry rock geothermal resources.Using the method of volume to evaluate geothermal resource of Liaoning province in the southeast Songliao basin.To deduce the total quantity of heat first-order tectonic units of Songliao basin,so do the second-order tectonic units of Dongnan basin.Calculated the total quantity of heat of Songliao basin is 1.37×1021KJ,it is equivalent 466.444 billion tons coal.The total quantity of heat is 139.98×1012KJ in the southeast uplift area geothermal where the Liaoning province location has the development potential.The total quantity of heat under 4km range accounts for 12.8%.Combined with present development and economic strength,the optimal excavation depth of 4000m is suitable for researching hot dry rock geothermal resource in Liaoning province.The main purpose of the application of supercritical carbon dioxide fluid in heating system of hot dry rock in order to improve the drilling speed and thermal efficiency.Analysis of the problems existing in the development of hot dry rock heating system in combination with related literature.Come to the conclusion that using SC-CO2 as heat with medium and drilling fluid can effectively solve these problems.By studying the properties of SC-CO2 fluid characteristics.Analysis the advantage of the technology in heat transfer process and the process of drilling.Arguments the feasibility of the application of SC-CO2 fluid for hot dry rock development.The main purpose of studying crack retention layer heat exchange process to argument SC-CO2 advantage.Hot dry rock heating systems in applied research stage is in a cold area of theoretical research stage,which dry hot rocks heat exchange heating system fractured reservoir studies remain layer is one of the most critical technical issues.Establish retention layer of fractured model,using software FLUENT to simulate the heat exchange process,using supercritical carbon dioxide SC-CO2 as a heat carrying medium,analysis retention layer temperature variation of SC-CO2 in cracks.Compare the system run 5 months.Comparison and contrast of SC-CO2 and water in the heat exchange process heat exchange rate and mining heat capacity,research and analysis of SC-CO2 as a heat medium to bring the advantages.By designing different simulation programs,studies of the impact on the heat exchange process when the crack width of the case and the fluid velocity change.Study on analyzes the main factors affecting the rate of heat transfer.Study on both application prospects and economy to proved the significance of theoretical hot dry rock heating system.And the impact is similar.The application prospect and economic analysis of hot dry rock heating system is to illustrate the purpose of this article research significance,and puts forward the main reasons hinder the development process.From environmental protection,safety,system heating analyze hot dry rock heating system application prospect.And point out that the present stage construction technology of fissure retention layer,drilling technology and cost is the main reason for blocking commercial application.Combining with the construction cost,with heat medium supply cost,maintenance cost and so on.Compared to the power generation cost of water and carbon dioxide in the conditions of different formation temperature and different injection-production pressure.It is concluded that the application of carbon dioxide heating medium has obvious advantages in economic aspect.Through numerical simulation concluded the conclusion that the thermal characteristics of SC-CO2 and design the experiment scheme,and put forward optimizing measures.