华南下扬子区泥页岩热物性测试与分析  

Measurement and Analysis of Thermal Properties of Mudstones and Shales in the Lower Yangtze Area,South China

作　　者：李香兰[1,2] 刘绍文[1,2] 徐明[3] 郝春艳[1,2] 王华玉[1,2] 

机构地区：[1]南京大学海岸与海岛开发教育部重点实验室,江苏南京210023 [2]南京大学地理与海洋科学学院,江苏南京210023 [3]天津地热勘查开发设计院,天津300250

出　　处：《天然气地球科学》2015年第8期1525-1533,共9页Natural Gas Geoscience

基　　金：国家重点基础研究发展计划项目课题(编号:2012CB214705);国家自然科学基金(编号:41176037;41272143);教育部新世纪优秀人才支持计划(编号:NCET-12-0263)联合资助

摘　　要：岩石热物性是研究盆地地热状态和构造—热演化过程的重要参数,也是盆地油气资源评价的重要研究内容之一。华南下扬子区是我国页岩气勘探开发的优选区块之一,页岩层系的热物性对于该区页岩气资源开发具有重要意义,但目前相关实测数据偏少,制约了对该区地温场及资源评价的认识。在18件泥页岩样品的热导率、生热率和密度等热物性参数测试的基础上,对下扬子区泥页岩的热物性进行了统计分析,并估算了整个扬子区的现今深部地层温度。研究表明,下扬子区泥页岩热导率大多数在1.500-3.000W/（m·K）之间,实测平均值为2.174±0.682W/（m·K）;生热率大多数在1.00-2.50μW/m3之间,大部分集中于2.00-2.50μW/m3之间,实测平均值为2.04±0.86μW/m^3。相比其他沉积岩类,页岩具有高生热率、低热导率的特殊热物性。样品间的热物性有相当大的变化,因此不能简单地以岩石的热物性作为区分岩石类型的指标。此外,扬子区的现今地温从东部的江浙皖（下扬子区）向西至上扬子区,表现为逐渐降低,但川东南地区和西南的楚雄盆地为高温区。下扬子区泥页岩的特殊热物性具有重要的地热涵义,这使得泥页岩类似保温盖层,其热屏蔽效应会导致页岩层及其下的地层温度升高,而页岩层之上的地层温度降低。这一特殊岩石热物性引起的温度异常势必改变深部地层的温度场分布,进而影响到烃源岩有机质热演化过程。研究区页岩气资源评价中必须考虑页岩的这一特殊的热物理性质。Thermal properties of rocks are the important parameters for studying the present-day geothermal regime and tectono-thermal evolution of the sedimentary basins,which would also provide fundamental data for the assessment and exploration of oil and gas resources in this basin.The Lower Yangtze area of the South China is considered as one of the preferred areas for shale gas exploration and development in China.The thermal properties of shales are of great significance for the exploration of shale gas resources in this area.However,the measured properties data of shales in this area are still rare,limiting our understanding of the geothermal field and resource assessment.In this study,thermal properties of 18 mudstone and shale samples from the Lower Yangtze area are measured,including the thermal conductivity,density and radiogenic heat production as well.Our results show that the values of thermal conductivity of shales generally range from 1.500W/（m·K）to 3.000W/（m·K）with a mean of 2.174±0.682W/（m·K）;while the values of radiogenic heat production basically vary from 1.00μW/m^3 to 2.50μW/m3 with a mean of 2.04±0.86μW/m3.Compared with other sedimentary rocks,the shale has unique thermal properties,and is characterized by a lower thermal conductivity and a higher radiogenic heat production.The thermal properties of the samples with same or similar lithology are somewhat different,indicative of their unavailability for distinguishing lithological types alone.Additionally,the estimated present-day subsurface formation temperature distribution pattern of the whole Yangtze area shows that the temperature gradually decreases from the Jiang-Zhe-Wan area（the Lower Yangtze area in the east）to the Upper Yangtze area in the west,but the temperatures in the southeastern Sichuan and the Chuxiong basins are relatively higher,which is the combination of local tectonics and variation in thermal properties.Generally,the shale bed is just like a heat insulation layer,owing to its low thermal conductivity,and

关 键 词：泥页岩 岩石热物性 热屏蔽效应 页岩气 下扬子区 

分 类 号：TE122.2[石油与天然气工程—油气勘探]