祁连山哈拉湖坳陷地质构造特征及天然气水合物成藏地质条件研究  

A study of geological structural features of Hala Lake Depression in Qilian Mountain and reservoir-forming conditions of natural gas hydrate

作　　者：何梅兴[1] 方慧[1] 祝有海 孙忠军[1] 胡祥云[3] 张鹏辉[1] 王小江[1] 裴发根[1] 仇根根[1] 杜炳锐[1] 吕琴音 HE Meixing;FANG Hui;ZHU Youhai;SUN Zhongjun;HU Xiangyun;ZHANG Penghui;WANG Xiaojiang;PEI Fagen;QIU Gengen;DU Bingrui;LU Qinyin(Institute of Geophysical and Geochemical Exploration,CAGS,Langfang,065000,Hebei,China;Oil and Gas Survey,China Geological Survey,Beijing 100083,China;Institute of Geophysics and Geomatics,China University of Geosciences,Wuhan 430074,Hubei,China)

机构地区：[1]中国地质科学院地球物理地球化学勘查研究所,河北廊坊065000 [2]中国地质调查局油气资源调查中心,北京100083 [3]中国地质大学地球物理与空间信息学院,湖北武汉430074

出　　处：《中国地质》2020年第1期173-187,共15页Geology in China

基　　金：中国地质调查局项目(DD20160224,DD20190030);基本科研业务费项目(JYYWF20180902,AS2017Y05)联合资助~~

摘　　要：祁连山哈拉湖坳陷与已发现天然气水合物的木里坳陷同属于南祁连盆地次级坳陷,有相似的水合物成藏条件,但由于该区地质工作程度低,坳陷内第四系覆盖层下的地质构造信息不清,对该区的天然气水合物成藏条件缺乏认识。为查明哈拉湖坳陷的地质构造特征和天然气水合物成藏条件,在哈拉湖坳陷区内开展了物化探综合探测及研究,结果表明:(1)调查区内可划分出4个凹陷区、2个凸起区,调查区内可划分出26条断裂;(2)调查区永冻土层分布特征以新生界沉积区以大面积片状和基岩出露区以岛状分布为主,永冻土层发育与高程、地形、地表覆盖层及表层土壤水分等因素密切相关;(3)调查区发现了两处地球化学异常,以酸解烃重烃、酸解烃干燥系数、顶空气甲烷和荧光光谱为指标组合,显示了两种不同的异常特征类型,异常浓集中心明显,强度较高;(4)哈拉湖坳陷的烃原岩条件相对差,烃源岩的保存完整性和印支-燕山期圈闭构造是水合物成藏的关键,哈拉湖坳陷区北部和地球化学Ⅰ号异常区可为水合物成藏远景区。本文为南祁连盆地下一步天然气水合物资源调查与评价提供了依据。Both of the Hala Lake Depression in Qilian Mountain and the Muli Depression in which natural gas hydrate was found are depressions of the South Qilian Basin and have similar hydrate accumulation conditions. However, due to the low degree of geological work in the Hala Lake Depression, the geological structure information in the depression under the Quaternary overburden is unclear, and the gas hydrate accumulation conditions in this area are not well understood. In order to find out the geological structure characteristics and gas hydrate accumulation conditions of the Hala Lake Depression, the authors carried out a comprehensive study of geophysical and geochemical exploration in the depression. Some conclusions have been reached:(1) The investigation area can be divided into four sags, two salients and twenty-six faults;(2) As for the distribution characteristics of permafrost layers in the investigation area, the Cenozoic sedimentary areas are mainly in sheet distribution in large area and the outcrops of bedrock are mainly in island-shaped distribution;the development of the permafrost layer is closely related to factors such as elevation, topography, land cover and surface soil moisture;(3) Two geochemical anomalies were found in the investigation area, and the indicators combination of heavy hydrocarbon in acidolysis hydrocarbons, aridity coefficient of acidolysis hydrocarbons, methane in headspace gases and fluorescence spectra characteristics indicates that there are two different types of anomalous features characterized by an obvious anomalous concentration center with relatively high intensity;(4) The source rocks in the Hala Lake Depression are relatively poor, and the preservation integrity of source rocks and the Indosinian-Yanshanian trap structure are the key factors to hydrate accumulation. The northern part of the Hala Lake Depression and the No. I geochemical anomaly zone can be the prospective areas for hydrate accumulation, and these findings provide a basis for future investigation and evalu

关 键 词：天然气水合物 成藏条件 冻土区 温压条件 哈拉湖坳陷 祁连山 油气地质调查工程 

分 类 号：P618.13[天文地球—矿床学]