长江下游区域地温场特征及其能源意义  

Geothermal regime of the lower reaches of Yangtze River and implications for resource exploration

作　　者：朱戈 刘绍文[1,2] 李香兰 吴迪 ZHU Ge;LIU Shaowen;LI Xianglan;WU Di(School of Geography and Ocean Science,Nanjing University,Key Laboratory of Coastal and Island Development,Minsistry of Education,Nanjing 210023,China;Collaborative Innovation Center for South China Sea Studies,Nanjing University,Nanjing 210093,China)

机构地区：[1]南京大学地理与海洋科学学院,海岸与海岛开发教育部重点实验室,江苏南京210023 [2]南京大学中国南海研究协同创新中心,江苏南京210093

出　　处：《地学前缘》2020年第1期25-34,共10页Earth Science Frontiers

基　　金：国家科技重大专项(2017ZX05-008-001);中国石油天然气股份有限公司科技创新项目(2015D-5006-0105);国家重点基础研究发展计划“973”项目(2012CB214703);南京大学大学生创新训练项目(G201610284013)。

摘　　要：区域地热特征及深部温度估算对于油气勘探和地热能资源评价和开发利用具有重要意义,长江下游地区是我国东部经济社会高度发达的地区,其能源需求大,区域热状态研究能为该区地热资源评价提供关键约束。通过整合长江下游地区已有的温度数据和实测岩石物性参数,勾勒出该区的现今地温场特征,并进一步估算其1000~5000m埋深处的地层温度。研究表明,长江下游地区现今地温梯度为16~41℃/km,且以18~25℃/km居多,苏北盆地区呈现高地温梯度。大地热流值为48~80mW/m^2,其均值为60mW/m^2,表现为中等的地热状态,有利于油气和地热能形成。此外,长江下游地区深部地温估算表明,1000m埋深处的温度范围为30~54℃,2000m时温度范围为50~95℃,3000m时温度范围为65~130℃,4000m时温度范围为80~170℃,5000m时温度范围为100~210℃。区域深部地温的展布趋势呈NE向,高温区域集中在安徽南部和江苏东北部。结合60℃和120℃等温线的埋深分布及区域地质、地球化学和地热特征,初步探讨了该区油气与地热资源的有利区带及其相应的开发利用类型。Geothermal energy,considered as one of new and emerging energies,has attracted increasing attention from academia and industry recently,owing to its huge potential and desirable attributes.Regional geothermal characteristics and deep temperature estimation are of great significances for geothermal energy exploration and utilization.The lower reaches of the Yangtze River in Eastern China is a region with welldeveloped socio-economic conditions and extremely large energy demand.However,the current regional geothermal regime is not well understood and needs further update with newly acquired geothermal data to provide insights into energy potential assessment in the region.In this article,we outlined the present-day geothermal gradient and heat flow pattern of the Lower Yangtze and estimated the temperatures at 1000-5000 m depth by integrating previously available regional geothermal data and newly measured thermal properties.The results showed that the geothermal regime of the Lower Yangtze area is mainly controlled by the neo-tectonics within the area.The geothermal gradient ranged from 16 to 41℃/km,with most areas between 18-25℃/km and an exception of 28-35℃/km in the northern Jiangsu area.While the heat flow varied from 48 to 80 mW/m^2 with a mean value of 60 mW/m^2,high heat flow was also found in the northern Jiangsu area and near the Tan-Lu fault zone,indicating the Lower Yangtze area is of a moderate to high geothermal regime favorable for hydrocarbon generation and geothermal energy exploitation.The estimated temperatures-at-depth were 30-54℃at 1000 m,50-95℃at 2000 m,65-130℃at 3000 m,80-170℃at 4000 m,and 100-210℃at 5000 m.Generally,the geothermal gradient showed a remarkable SW-NE striking,with high temperature anomalies distributed in the southern Anhui and northeastern Jiangsu areas,suggesting potential targets of geothermal energy utilization in the two areas.In addition,we also determined the isothermal depth patterns at 60 and 120℃.On the basis of geological,geochemical and geothermal

关 键 词：长江下游 热状态 深部地温 地热资源 

分 类 号：P314[天文地球—固体地球物理学]