祁连山哈拉湖坳陷天然气水合物地球化学勘查  

Geochemical exploration of natural gas hydrate in Halahu Depression of Qilian Mountain

作　　者：孙忠军 王惠艳[1,2,3] 张舜尧 周亚龙[1,2,3] 张富贵 杨志斌[1,2,3] 

机构地区：[1]国家现代地质勘查工程技术研究中心,河北廊坊065000 [2]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 [3]中国地质科学院地球表层碳-汞地球化学循环重点实验室,河北廊坊065000

出　　处：《物探与化探》2017年第6期1152-1159,共8页Geophysical and Geochemical Exploration

基　　金：国土资源部公益性行业科研专项项目(201111019);国家127专项项目(GZHL20110324;GZH201400302)

摘　　要：自祁连山冻土区木里坳陷发现天然气水合物以来,南祁连盆地开始成为中纬度冻土区天然气水合物调查的重点地区。2014年在哈拉湖坳陷开展了1∶10万地球化学调查,目的是为天然气水合物远景预测提供地球化学依据。调查面积3 000 km^2,采样密度1点/2 km^2,分析了天然气水合物和油气化探指标。在哈拉湖坳陷圈出了与三露天水合物矿藏类似的地球化学综合异常,面积大于30 km^2,异常组合为酸解烃甲烷、酸解烃干燥系数、丁烷异构比、顶空气甲烷和荧光F320,这些指标存在组分分带现象。进一步研究表明,烃类气体主要来源于深部的凝析油伴生气和煤型气,异常区发育有利于天然气水合物形成的冻土厚度。调查结果表明,地球化学技术适用于中纬度冻土区天然气水合物勘查,能够圈出天然气水合物远景区。South Qilian basin has become the key area of natural gas hydrate survey in the mid-latitude permafrost since natural gas hy- drate was discovered in Halahu Depression. The 1：100000 geochemical survey was carried out to provide evidence for prospective prog- nosis of natural gas hydrate in Halahu Depression in 2014. Natural gas hydrate and oil-gas geochemical indexes were analyzed in 3000 km2 survey area, with the sampling density being 1 sampling site per 2 km~. Geochemical anomalies （ 〉30km2 ） similar to Sanlutian hy- drate despoit were delineated, where the abnormal combination of acidolysis methane, acidolysis aridity coefficient, butane isomeriza- tion rate, headspace methane and fluorescence 320 exhibited compositional zoning. Further studies show that condensate and coal-type gas were the main source of hydrocarbon gas, and the development of abnormal area was beneficial to the formation of the depth of natu- ral gas hydrate. The results of the survey show that the geochemical technique is suitable for the exploration of natural gas hydrate in the mid-latitude permafrost, and could delineate the prospective area of natural gas hydrate.

关 键 词：天然气水合物勘查 地球化学 水合物远景 哈拉湖坳陷 冻土区 

分 类 号：P632[天文地球—地质矿产勘探]