二氧化碳基增强型地热系统储层换热研究现状及展望  

Heat transfer in geothermal reservoir of CO_(2)-based enhanced geothermal systems—current research status and prospects

作　　者：蒋政 舒彪[1] 谭静强 JIANG Zheng;SHU Biao;TAN Jingqiang(School of Geosciences and Info-physics,Central South University,Changsha 410083,China)

机构地区：[1]中南大学地球科学与信息物理学院,湖南长沙410083

出　　处：《地学前缘》2024年第6期235-251,共17页Earth Science Frontiers

基　　金：国家重点研发计划项目(2023YFE0119700);国家自然科学基金面上项目(42072304);湖南省科技创新计划项目(2021RC3009)。

摘　　要：干热岩资源分布广泛、储量巨大,被认为是具有广阔发展前景的绿色能源之一,而增强型地热系统(EGS)是开采干热岩资源的主要技术方法。在CO_(2)-EGS中,超临界CO_(2)(ScCO_(2))作为取热工质可以减少水资源浪费、降低泵送能量消耗,比H_(2)O具有更高的传热效率,并且可以实现部分CO_(2)的地质封存,具有较大的发展前景。本文从EGS裂隙储层模型、CO_(2)的物理性质,以及CO_(2)在储层裂隙中的流动与传热特性3个方面,总结了CO_(2)-EGS储层换热技术的研究进展,并针对我国典型地热场地的实际应用提出了建议。结果表明,裂隙性多孔介质模型更为实用和高效,而局部非热平衡模型更符合实际情况。CO_(2)具有较高质量流率和较轻微的矿物溶解能力,其矿化封存可降低地震风险,但会使储层的渗透率下降,建议调整主裂缝的非接触面积或CO_(2)的注入参数以减少渗透率的降低。未来应深入研究CO_(2)的非达西流动特性,并探究CO_(2)在共和与松辽盆地储层中的损失问题以及福建漳州凝灰岩盖层对CO_(2)的封存能力。Hot dry rock(HDR)resources with large reserves are widely distributed.HDR is considered one of the sources of green energy with a broad development prospect,and the enhanced geothermal systems(EGS)is the main technology to mine HDR resources.In CO_(2)-EGS,supercritical CO_(2)(ScCO_(2))used as a working fluid for heat extraction can reduce water and energy consumption in pumping.ScCO_(2)is a better(higher efficiency)heat transfer fluid than H_(2)O and can be used for geological storage of partial CO_(2),which has a large development prospect.This paper summarizes recent research progres on heat transfer techniques used in CO_(2)-EGS from three aspects:reservoir fracture models for EGS,physical properties of CO_(2),and flow and heat transfer properties of CO_(2)in reservoir fractures.Suggestions on practical application at typical geothermal sites in China are presented.The fracture model based on fractured,porous medium is more practical and efficient,and the local thermal non-equilibrium model is more accurate.CO_(2)has a high mass flow rate and low mineral dissolution capability,and CO_(2)mineralization and storage in EGS can reduce seismic risk.However,it will decrease the permeability of the reservoir,and it is recommended to adjust the non-contact area of the main fracture or the CO_(2)injection parameter to minimize the permeability decrease.In the future,the non-Darcy flow properties of CO_(2)should be further investigated.When exploring the practical application of CO_(2)-EGS in the Gonghe and Songliao Basins,the loss of CO_(2)in the reservoirs should be considered,and the sealing performance of the tuff caprock in Zhangzhou,Fujian Province should be evaluated.

关 键 词：地热储层 干热岩 增强型地热系统 二氧化碳 渗流传热 

分 类 号：P314[天文地球—固体地球物理学]