四川盆地地热地质条件及勘探潜力评价  

A preliminary study of the geothermal geological characteristics and exploration potential of the Sichuan Basin

作　　者：孙东 李金玺[2] 曹楠 李智武 张志鹏[1,3] 谢小国 袁梦雨 蔡鸿燕 SUN Dong;LI Jinxi;CAO Nan;LI Zhiwu;ZHANG Zhipeng;XIE Xiaoguo;YUAN Mengyu;CAI Hongyan(Sichuan Geological Environment Survey and Research Center,Chengdu,Sichuan 610081,China;Key Laboratory of Earth Exploration and Information Techniques,Ministry of Education(Chengdu University of Technology),Chengdu,Sichuan 610059,China;Sichuan Huadi Construction Engineering Co.Ltd.,Chengdu,Sichuan 610081,China)

机构地区：[1]四川省地质环境调查研究中心,四川成都610081 [2]地球勘探与信息技术教育部重点实验室(成都理工大学),四川成都610059 [3]四川省华地建设工程有限责任公司,四川成都610081

出　　处：《水文地质工程地质》2023年第3期193-206,共14页Hydrogeology & Engineering Geology

基　　金：国家自然科学基金项目(41602153,41472107,41230313)。

摘　　要：地处特提斯—喜马拉雅构造域与滨太平洋构造域交接转换部位的四川盆地,是造山带环绕的多旋回沉积盆地,地热资源禀赋较好,但地质构造复杂,不同构造带地热条件和成热模式差异较大,严重制约地热勘探开发与利用。在四川盆地已有地热勘探开发资料和油气勘探研究成果的基础上,系统总结了四川盆地的地热储层、地热流体、大地热流和地温梯度场的特征及分布规律,对比研究了四川盆地不同类型盆山结构区的地热储盖层组合和地热条件的异同性,指明了不同构造单元的勘探靶区。结果表明:(1)四川盆地及周缘的大地热流值为中低热流值,地温梯度在16~30℃/km之间,地热源受活动断裂和基底构造控制明显,发育传导型水热系统,多属中低温(<90℃)地热资源;(2)四川盆地的地热资源分布主要受盆地构造、地层分布和水文条件等控制;(3)海相层系至少存在4个岩溶型热储层,陆相地层局部偶夹1~2个砂砾岩型热储层,地下水多为SO_(4)—Ca型微咸水。研究建议以中~下三叠统和中二叠统岩溶型热储为重点层系,尤其在川东和和川西地区二者勘探潜力较大,其次优选其他海相层系岩溶型热储进行勘探,而陆相碎屑岩热储层盖层、地下水补给和热源等条件较差,勘探潜力一般,开发风险高且需谨慎。该研究可为四川盆地地热勘探开发利用提供理论依据。The Sichuan Basin located in the intersection of the Tethys−Himalaya and Pacific domains is a multicycle sedimentary basin surrounded by orogenic belts.The geothermal resources are good,but with complex geological structures.Geothermal conditions and heat generation models are different in different tectonic zones in the basin,which seriously restrict the geothermal exploration,development and utilization of geothermal resources.In this paper,the distribution of geothermal resources,characteristics of geothermal fluids,heat flow and geothermal gradients in the Sichuan Basin are comprehensively analyzed by collecting the existing geothermal and petroleum exploration and development data.The geothermal reservoirs and caprocks,the burial depth and the resource conditions of different types of the basin-mountain structure areas in the Sichuan Basin are analyzed.The suggested exploration target for exploration and development are proposed in different tectonic units of the Sichuan Basin.The results show(1)the terrestrial heat flow values in the Sichuan Basin and its surrounding areas are from medium to low,and the geothermal gradient varies between 16℃/km and 30℃/km.The terrestrial heat source is obviously controlled by active faults and basement structure,and the hydrothermal systems are conductive and belong to the low-moderate temperature geothermal resources in the Sichuan Basin.(2)The distribution of geothermal resources in the Sichuan Basin is mainly controlled by basin structure,stratigraphic distribution and hydrologic conditions.(4)There are at least 4 karst-type geothermal reservoirs in the marine strata,and 1−2 glutenite-type geothermal reservoirs in clastic strata.Geothermal water is of SO_(4)-Ca type and is brackish.The Middle-Lower Triassic and Middle Permian carbonate rocks are considered as the best marine reservoirs,especially in the eastern and western basin.Secondly,other marine karst-type geothermal reservoirs are selected for exploration.The continental clastic rocks should be cautious bec

关 键 词：地热地质 地质构造 地热资源 地热储盖层 四川盆地 

分 类 号：P314.1[天文地球—固体地球物理学]