Numerical Simulation Research On Multi-Field Coupling Of Middle-Deep Geothermal Development Process In Xiwenzhuang Taiyuan

Since the second industrial revolution,the use of fossil energy such as coal,oil,and natural gas has greatly increased the speed of social development,but the ensuing energy depletion,air pollution and other issues have been plagued today's society.People urgently need a solution.Clean and environmentally friendly renewable energy is used to ensure the sustainable development of society,and geothermal energy is such a green energy.However,due to the limitations of geothermal energy extraction technology and disorderly management of the geothermal energy extraction process,most of the current geothermal wells have problems such as short development life,low production efficiency,and rapid decline in ground temperature,which severely restrict the development of geothermal energy.At present,the most widely used geothermal development methods at home and abroad are wellbore heat exchange and fluid exchange development methods.Therefore,this article will focus on these two typical geothermal development methods,based on drilling data,field tests and theoretical analysis,and use numerical simulations.The technology studies the influence of different geological parameters and engineering parameters on the thermal performance of these two typical geothermal development systems,optimizes the plan,compares and analyzes the advantages and disadvantages of the two development methods,and proposes a more reasonable development plan.The Xiwenzhuang geothermal field is located in the Taiyuan Basin,which is a Cenozoic rift basin with a high terrain in the north and low in the south.The east and west are high and the middle is low,which belongs to the medium and low temperature conductive geothermal system.In this paper,two sets of mid-deep geothermal wells in the Xiwenzhuang geothermal field of Taiyuan Basin are used as the research object.Based on the summary and analysis of the heat storage distribution characteristics,geothermal characteristics,hydrogeological characteristics and drilling data in the Xiwenzhuang area,numerical simulation technology is used to analyze the simulated ground.Research on the heat recovery efficiency of geothermal wells under different conditions in the process of thermal energy extraction.The specific research work of the thesis is as follows:(1)Summarize and analyze the geological structure characteristics,thermal reservoir characteristics,hydrogeological conditions and hydrochemical characteristics of the Xiwenzhuang geothermal field based on literature data,field engineering data and test data,and provide the most basic geological data for mathematical modeling.(2)Based on the distribution characteristics,geothermal characteristics,hydrogeological characteristics and drilling data of Taiyuan's Xiwenzhuang geothermal field,a mathematical model that meets the geological conditions of the area has been established.Based on the mathematical model,a seepage and heat transfer model of the middle-deep thermal storage under the coupling effect of temperature-stress-seepage multi-field is established;at the same time,a geothermal exploitation model of the middeep coaxial heat exchanger is also established to study the similarities and differences of the two geothermal systems in the process of extracting geothermal energy.(3)According to the numerical simulation results,the influence of geothermal energy on the heat recovery performance of the well system is analyzed by the formation parameters such as permeability,formation thermal conductivity,and reservoir heat capacity,and engineering parameters such as injection temperature,injection pressure,and wellbore spacing.At the same time,we studied the influence of formation parameters such as formation thermal conductivity,reservoir heat capacity and geothermal gradient,as well as injection temperature,injection speed,backfill material and heat exchanger tube diameter on the heat recovery performance of the coaxial heat exchanger geothermal system.(4)On the basis of single factor analysis,the development plan of the two geothermal development systems was optimized by "Analysis Hierarchy-Fuzzy Mathematics",we have analyzed their development performance and discussed their applicable conditions according to the optimized results.