Research On The Forward And Inversion Method Of Heat-flow Coupling In The Development Of Deep Resources

As energy demand continues to increase,resource development continues to explore deep underground.In the process,a series of problems pose challenges to the development of deep resources,such as the high pressure and high temperature of the deep rock,the aggravated degree of rock mass rupture,and the difficulty of underground measurement conditions.In order to make resource development safer,greener and more efficient,it is necessary to research on the forward develop models and the inversion of measured data.Unconventional oil and gas reservoirs are an important part of deep resources and have become an significant replacement for conventional oil and gas resources.Geothermal resources are also an important part of deep resources.The rational development of geothermal resources can not only relieve energy demand,but also reduce air pollution caused by the burning of fossil fuels such as oil and coal.In the development process of the above-mentioned energy,the bottom hole temperature and pressure can be obtained with the progress of science and technology.Especially due to the application of optical fiber technology,three-dimensional data of temperature changes along the wellbore and over time can be obtained.The rational utilize of wellbore temperature data become increasingly important.Therefore,on the basis of the above mentioned resource development methods,this paper studies the physical models of vertical wells,horizontal wells,formation fractures,and dual well systems,and the heat flow coupling equations of wellbore and formation is established.In addition,we carry out a series of research on forward models and inversion methods.The main contents and innovative findings of this study are described as follows:1.The heat flow coupling models of wellbore/reservoir/non-producing formation for different resources development such as tight oil,shale gas,and dry hot rock are established.The model can simulate and predict the pressure and temperature distribution of multi-component and multi-phase fluids under non-isothermal conditions.In order to ensure the accuracy of the proposed model,this paper compares the wellbore model and the formation fracture model with analytical solutions,and performs temperature history matching on the simulated temperature data with the measured data of an example well.The established model is the theoretical basis for temperature behavior analysis and wellbore temperature data inversion.2.A new temperature well testing method for the deep and high production wells is proposed.Aiming at the phenomenon of abnormally rising bottom hole temperature in the deep and high production wells,we propose a simplified vertical well heat transfer model,especially considering the Joule-Thomson effect of the fluid,which reasonably explains the reason for the temperature rises.3.A dual-well enhanced geothermal system(EGS)discrete fracture model is established.Aiming at EGS composed of production well,injection well,reservoir and fractures,considering the location distribution of natural fractures and the generation of hydraulic fractures,a discrete fracture model is established.The deep reservoir is described reasonably by solving the equations.4.A new piecewise linear integral function inversion method is proposed for the development of shallow geothermal energy.Because the measurement data of geothermal wells is mainly near the wellhead,the pressure and temperature data of the wellhead are converted to the bottom hole through the wellbore heat transfer model.Aiming at the constantly changing characteristics of flow rate and pressure of geothermal wells,a method for efficient utilization of pressure and temperature data is proposed.5.The application of wellbore temperature data in multi-stage fractured horizontal wells for fracture diagnosis is studied.Considering that the traditional pressure analysis method is difficult to avoid the ambiguity problem in fracture diagnosis,the integrated workflow of temperature transient analysis and pressure transient analysis is proposed for the first time to more accurately determine the fracture information in the reservoir.