热-流-固全耦合下的干热岩热采效率研究——以青海共和GR1井为例  

Geothermal extraction efficiency of dry hot rock based on a fully coupled thermo-hydro-mechanical model:Taking the GR1 well in Gonghe,Qinghai as an example

作　　者：李佳豪 祝爱玉[1] 崔光磊 李迎春 Li Jiahao;Zhu Aiyu;Cui Guanglei;Li Yingchun(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines,Northeastern University,Shenyang 110819,China;State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]东北大学深部金属矿山安全开采教育部重点实验室,沈阳110819 [3]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024

出　　处：《地震学报》2025年第2期200-220,共21页Acta Seismologica Sinica

基　　金：国家自然科学基金面上项目(42374120);中国地震局地球物理研究所基本科研业务费专项(DQJB23B25)联合资助。

摘　　要：建立了热-流-固全耦合模型,考虑了流体压力变化和温度变化引起的储层变形、受储层变形影响的储层孔隙率、渗透率和断层裂隙开度、受温度控制的流体性质(密度、黏度等)和流体流动引起的热传导,以青海共和GR1井为例,研究了定流量和定压力两种典型生产模式下,储层渗透率、断层渗透类型对于地热资源(干热岩)开发过程的影响。研究结果表明:(1)定压力生产模式下,阻隔型断层降低了地热开采效率,提升热储层渗透率可以大幅度提高地热开采效率,但是过高的渗透率会造成资源浪费,不利于持续性开采;(2)定流量生产模式下,地质因素对地热开采效率的影响很小,开采效率主要由注采速率决定;(3)从安全角度看,在定流量模式下,过小的渗透率和阻隔型断层会引起很大的孔隙压力响应,导致一系列施工安全问题;(4)对于青海共和地区的地热开采,应综合考虑开采效率和施工安全,建议若采用定压生产模式,需将储层渗透率改造至1×10^(-13)—1×10^(-12)m^(2)的范围内,若采用定流生产模式,需将储层渗透率改造为1×10^(-13)m^(2)以上,且两种生产模式都应避免注水井与生产井之间存在阻隔型断层。Developing deep dry hot rock resources is widely regarded as crucial for addressing China’s energy security issues and achieving its“dual carbon”goals.However,extracting this type of energy is a significant challenge due to its location in complex geological environments characterized by high temperature and high pressure.The mining process is intricately linked to the multifaceted interactions of seepage,mechanics,and temperature.Consequently,establishing a thermo-hydro-mechanical coupling model that incorporates various physical factors is essential for studying the interactions and impacts of enhanced geothermal systems(dry hot rock).This study introduces a fully coupled thermo-hydraulic-mechanical model designed to investigate the effects of permeability and fault characteristics on the efficiency of geothermal extraction in hot dry rock reservoirs.The model thoroughly considers the interactions among multiple physical fields,including:①reservoir deformation caused by changes in fluid pressure and temperature;②variation of porosity,permeability,and fracture openings due to reservoir deformation;③temperature-dependent fluid properties(e.g.,density,viscosity);and④heat conduction resulting from fluid flow.The Gonghe Basin in Qinghai Province is known for its abundant hot dry rock resources,notably the GR1 hot dry rock exploration well,which has the highest temperature recorded for hot dry rock drilled in China.This paper uses the GR1 well as a case study to develop a threedimensional numerical model that examines how reservoir permeability and fault characteristics affect geothermal extraction efficiency in different production modes,specifically constant pressure and constant injection rate production.Additionally,we analyzed the combined effects of these factors on production efficiency and operational safety.The research findings indicate:1)In the constant pressure production mode,low-permeability reservoirs and barrier-type faults significantly reduce geothermal extraction efficiency.These feat

关 键 词：热-流-固耦合 青海共和干热岩 采热效率 数值模拟 

分 类 号：P314.2[天文地球—固体地球物理学]