超临界二氧化碳开采干热岩热量过程中裂隙网络的热流固耦合分析

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关键词：地热能；干热岩；裂隙储层；超临界二氧化碳；多物理场中图分类号：TK521.1文献标志码：ADOI：10.7652/xjtuxb202602008 文章编号：0253-987X（2026）02-0082-10

Thermo-Hydro-Mechanical Coupling Analysis of Fracture Networks During Heat Extraction from Hot Dry Rock Using Supercritical Carbon Dioxide

QIAO Mingzheng， JING Zefeng， ZHOU Yujuan， ZHENG Long，WANG Lichao （School of Energy and Power Engineering，Xi'an Jiaotong University，Xi'an 7l0049，China）

Abstract： To address the unclear issues concerning the evolution of properties in fractured reservoirs under multi-physical field coupling effects and the influence of fracture network connectivity on thermal extraction performance during the development of deep geothermal energy from hot dry rock using supercritical carbon dioxide （ ：SC-CO2 ），a numerical simulation study was conducted. The thermo-hydro-mechanical（THM） coupling in fractured reservoir networks was investigated， and the heat extraction processes of fracture networks under diferent fracturing conditions were simulated. A comparison of heat extraction efficiency was made between SC-CO2 and water as working fluids，the evolution of reservoir properties was explored，and the impact of fracture network connectivity on various physical fields and reservoir characteristics was analyzed. The results indicate that，compared with water， SC-CO2 yields a higher production temperature，a slower temperature decline trend，and less impact on reservoir displacement，rendering it more suitable for long-term extraction. The production temperature of the multi-hydraulic fracture network is approximately 24K higher than that of the single hydraulic fracture network. In a single hydraulic fracture network，an increase in disconnection distance delays the temperature decline but raises the pressure loss. In multi-hydraulic fracture networks，disconnection reduces the heat exchange area and total heat transfer， yet does not afect the thermal breakthrough time. Reservoir porosity， permeability，and fracture aperture are significantly influenced by THM coupling. Notably，the fracture aperture near the wellbore undergoes drastic changes due to the high fluid pressure gradient. This study provides a theoretical basis for the optimization of fracture networks and efficient heat extraction in enhanced geothermal systems.

Keywords： geothermal energy； hot dry rock；fractured reservoir; supercritical carbon dioxide; multi-physics field

干热岩地热能作为一种清洁且可持续的能源形式，储量丰富且来源稳定，已成为地热能开发的重要方向[]。（剩余14821字）