Thermal Stability And Economic Evaluation Of Dry-hot Rock Thermal Reservoir

Geothermal energy is a kind of green,low-carbon,recyclable and renewable energy.It has the characteristics of large storage,clean and environmental protection,stability and reliability.Dry thermal rock is one of geothermal energy,and its energy storage can occupy approximately geothermal energy.One third of the total resources.Therefore,in recent years,the use of dry hot rock power generation for heating has become a hotspot for people's research.Although the dry hot rock heating technology is easier to implement than power generation,the heat generation stability and heat production effect of heat reservoirs in heating applications Still need to explore and study.The thesis comparatively analyzes the fracturing techniques of diferent dry-hot rock thermal reservoirs,and fin ds that the number of fractures formed by carbon dioxide fracturing is large,evenly distributed,and the width of the fracture is suitable.It is obtained that the advantages of carbon dioxide cracking are obviou s in terms of crack shape and impact on rock mass and environment.In this paper,a single-fracture thermal reservoir model is established for the dry-hot rock double-well replacement system.Fluent software is used to simulate the system's fracture width,working fluid flow rate,and initial formation temperature to the production well during a heating cycle(five months).The influence of the water temperature,the temperature distribution of the rock layer around the fracture,the temperature of the working fluid in the fracture,and the rate of heat production.The results show that the initial temperature of the rock layer has a significant effect on the outlet tem perature and heat production rate of the production well.The larger the initial temperature.the greater the outlet temperature and heat production rate of the production well,and the larger the heat extraction radius around the fracture.The temperature of the exploitation of the basic model thermal reservoir has been simulated for ten years of continuous operation.The continuous heating of the system can not meet the heating demand for about six and a half years.However,in this paper,dry hot rock is used for heating,and heat recovery can be performed during the non-heating period.The operating life of the system is very long.The dry-heat rock heating system in the article can meet the heating building area of about 790,000 square meters and the return on investment applied in practice is 450%.Similarly,geothermal energy is used to heat the cold area,from the initial investment,system operation costs,etc.See if the system is running for a long time,the dry heat rock heating system has higher economy than the ground source heat pump system.Although the initial investment of the dry hot rock heating system is relatively large,its application economy is very high,and long-term operation benefits from all aspects and has broad prospects.