琼东南盆地和郁陵盆地天然气水合物成藏对比研究  

Comparative study of gas hydrate accumulation system in the Qiongdongnan Basin of the South China Sea and the Ulleung Basin of Korea

作　　者：黄伟 张伟[1,2] 梁金强[1,2] 尚久靖[1,2] 孟苗苗[1,2] 单晨晨 HUANG Wei;ZHANG Wei;LIANG Jinqiang;SHANG Jiujing;MENG Miaomiao;SHAN Chenchen(Key Laboratory of Marine Mineral Resources,Guangzhou Marine Geological Survey,Ministry of Natural Resources,Guangzhou,Guangdong 510760,China;Natural Gas Hydrate Engineering Technology Center,China Geological Survey,Guangzhou,Guangdong 510760,China)

机构地区：[1]广州海洋地质调查局自然资源部海底矿产资源重点实验室,广东广州510760 [2]中国地质调查局天然气水合物工程技术中心,广东广州510760

出　　处：《中国矿业大学学报》2021年第2期363-380,共18页Journal of China University of Mining & Technology

基　　金：国家自然科学基金项目(41806071);国家重点研发计划项目(2018YFE0208200);中国地质调查局项目(DD20190222);自然资源部海底矿产资源重点实验室开放基金(KLMMR-2018-A-05)。

摘　　要：南海北部陆坡琼东南盆地和韩国郁陵盆地开展了多次天然气水合物(简称水合物)钻探并获取了水合物实物样品,揭示出两盆地具有良好的水合物资源前景及勘探潜力.为加深不同构造背景下水合物成藏理论及科学指导水合物勘探部署,本文基于琼东南盆地和郁陵盆地地质、地球物理、地球化学分析并结合水合物钻探成果,从水合物成藏系统角度对两盆地水合物藏的气源条件、输导条件、储集条件、稳定域条件开展综合对比,深入研究了两盆地水合物成藏特征的异同及控藏机制,建立了琼东南盆地"深部超压驱动—混合气源供给—多元流体输导—块体流封闭型"和郁陵盆地"浅层沉积变形—生物气源供给—气烟囱输导—块体流封闭型"两种水合物成藏模式,认为"气烟囱"和"块体流"的耦合作用是两盆地"渗漏型"水合物藏形成及块状水合物赋存的主控因素.研究结果表明:两盆地均属典型"热盆",含气流体活动更加剧了海底浅层局部高地温场产生,地温梯度可到90℃/km以上.琼东南盆地水合物气源为热成因气和生物成因气的混合气,δ^(13)C_(CH4)总体大于-60‰,C_(1)/C_(2+)<1000,输导通道多为构造断层、气烟囱、泥底辟,浅层水合物藏与深层常规气藏在气体来源、流体输导特征上具有密切联系,块体流主要通过物性封盖和"温度-压力"封闭作用控制水合物成藏;郁陵盆地水合物气源为浅层生物成因气,δ^(13)C_(CH4)几乎全部小于-60‰,C_(1)/C_(2+)>1000,输导通道主要为小型断层及微裂隙,块体流主要通过影响浅层沉积变形及储层结构局部优化,控制生物气的运聚和水合物成藏.琼东南盆地深水区南部隆起带将是未来水合物勘探的有利区.Several natural gas hydrate(gas hydrate for short)drillings have been carried out in the Qiongdongnan Basin of the South China Sea and the Ulleung Basin of Korea,respectively,and gas hydrate samples were obtained,revealing a good prospect of gas hydrate resources and exploration potential.Drilling results demonstrated that the gas hydrates in two basins show many similarities in terms of gas hydrate occurrence status,accumulation characteristics,and enrichment mechanisms.In order to deepen the gas hydrate accumulation theory under different tectonic backgrounds and guide gas hydrate exploration and deployment scientifically,based on the geological,geophysical,and geochemical analysis as well as the gas hydrate drilling results in Qiongdongnan Basin and Ulleung Basin,this article conducted a comparative study on the gas source conditions,gas migration conditions,reservoir conditions,and the gas hydrate stability zone conditions in the two basins and profoundly studied the similarities and differences in the characteristics of gas hydrate accumulation as well as the controlling mechanism between two basins.The gas hydrate accumulation model of"overpressure driven by deep layer-mixed gas supply-variable gas migration pathways-mass transport deposit sealing"in the Qiongdongnan Basin and"shallow sedimentary deformation-biological gas supply-gas chimney pathway-mass transport deposit sealing"in the Ulleung Basin were established on the basis above,respectively.The coupling of"gas chimney"and"mass transport deposits"were considered to be the main controlling factors that control the formation of"leakage type"gas hydrate and the occurrence of massive gas hydrate reservoirs in the two basins.The research results showed that the Qiongdongnan Basin and Ulleung Basin are typical"hot basins".The gas-bearing fluid activity intensified local high geothermal field in the shallow layer that results in the geothermal gradient reaching more than 90℃/km.In terms of the Qiongdongnan Basin,gas source of hydrate is a mixture of therm

关 键 词：天然气水合物 水合物成藏系统 琼东南盆地 郁陵盆地 对比研究 

分 类 号：P618[天文地球—矿床学]