摘要
共和盆地地处青藏高原东北缘,是我国干热岩地热资源研究的热点与高地.多年来,学术界开展了一系列多尺度、多维度、多手段的联合研究,在该区基础地热地质、干热岩热源机制与成因模式、热储改造与开发潜力等多方面形成了众多成果与认识.但是,目前关于干热岩地热资源分布的研究仍相对匮乏.因此,本论文以近年来在盆地东北部新完钻的钻井为依托,通过开展钻孔系统稳态温度测量,同时结合已有岩石热导率数据,计算获得了6个新的大地热流值,在此基础上,分析了盆地东北部热流分布规律及热流异常特征,并进一步探讨了热流分布的主要影响因素与干热岩地热资源的分布特征.结果显示,盆地东北部沉积层的地温梯度介于47.8~80.2℃·km^(-1)之间,平均值为60.4±10.5℃·km^(-1),大地热流值介于76.0~127.5 mW·m^(-2)之间,平均值为98.7±15.7 mW·m^(-2),约为我国大陆地区平均大地热流的1.6倍.大地热流平面分布展现出明显的西低东高的整体特征,且在东侧高热流分布区,热流具有由南至北逐渐增高的趋势.综合分析认为,热流空间变化与壳内局部部分熔融层、基底起伏引起的岩石热物性横向不均一和盆地北缘的青海南山断裂带等因素密切相关.热流异常特征指明研究区东部的干热岩地热资源潜力明显优于西部.在未来干热岩勘探中,除现有干热岩钻井分布区外,其北侧的青海南山山前区域应予以高度关注和重视.
The Gonghe basin,located on the northeastern margin of the Qinghai-Tibet Plateau,is a hotspot and highland for the study of hot dry rock(HDR)geothermal resources in China.Over the years,the academic community has conducted a series of collaborative studies on various scales,dimensions,and methodologies in this area,resulting in significant achievements and insights into various aspects such as basic geothermal geology characteristics,heat source mechanisms and genesis models of HDR geothermal resources,reservoir construction,and development potential.However,research on the distribution of HDR geothermal resources in this area remains relatively limited.Therefore,based on the boreholes newly drilled in the northeastern part of the basin,this study conducts borehole steady-state temperature logging.Combined with the temperature data obtained newly and the available rock thermal conductivities,six new terrestrial heat flow values were calculated.Based on this,the distribution patterns and anomaly characteristics of heat flow have been analyzed.Additionally,the main influencing factors of heat flow distribution and the distribution characteristics of HDR geothermal resources were further discussed.The results indicate that the geothermal gradient of the sedimentary layer ranges from 47.8 to 80.2℃·km^(-1),with an average value of 60.4±10.5℃·km^(-1).The terrestrial heat flow ranges from 76.0 to 127.5 mW·m^(-2),yielding an average value of 98.7±15.7 mW·m^(-2),approximately 1.6 times the average heat flow in China's Mainland.The spatial distribution of heat flow demonstrates a clear overall pattern of low in the west and high in the east.Besides,in the eastern part which is characterized by high heat flow,there is a gradual increase in heat flow from south to north.Comprehensive analysis suggests that the spatial variation of heat flow is closely related to factors including the local partial melting layers in the crust,lateral heterogeneity of rock thermal properties caused by basement undulation,and the Qinghai Nanshan fault at the northern margin of the basin.The anomaly characteristics of heat flow indicate that the potential of HDR geothermal resources in the eastern part of the study area is significantly better than that in the western part.In the future exploration,besides the existing distribution area of HDR boreholes,attention and importance should also be placed on the foreland area of the Qinghai Nanshan to the north.
作者
张超
冯庆达
张盛生
张林友
姜光政
胡圣标
张森琦
张浩竹
廖传志
黄荣华
ZHANG Chao;FENG QingDa;ZHANG ShengSheng;ZHANG LinYou;JIANG GuangZheng;HU ShengBiao;ZHANG SenQi;ZHANG HaoZhu;LIAO ChuanZhi;HUANG RongHua(College of Energy,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Center for Hydrogeology and Environmental Geology,China Geological Survey,Tianjing 300000,China;The Survey Institute of Hydrogeology,Engineering Geology and Environment Geology of Qinghai Province,Xining 810008,China;State Key Laboratory of Lithospheric and Environmental Coevolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《地球物理学报》
北大核心
2025年第9期3503-3518,共16页
Chinese Journal of Geophysics
基金
国家自然科学基金(42102337,42074096)
四川省科技计划项目(2023NSFSC0252)联合资助.
关键词
钻孔系统稳态温度测量
大地热流
干热岩
热流异常
共和盆地
Borehole steady-state temperature logging
Terrestrial heat flow
Hot dry rock
Heat flow anomaly
Gonghe basin
