青藏高原乌丽冻土区烃源岩地球化学特征  

Molecular Geochemical Characteristics of Potential Source Rocks of the Wuli Premofrost in the Tibet Plateau,China

作　　者：陈小慧[1,2] 张敏 龚建明[3] 

机构地区：[1]长江大学地球环境与水资源学院,湖北武汉430100 [2]油气资源与勘探技术教育部重点实验室(长江大学),湖北武汉430100 [3]青岛海洋地质研究所,山东青岛266071

出　　处：《天然气地球科学》2014年第6期882-888,共7页Natural Gas Geoscience

基　　金：湖北省教育厅科学技术研究计划青年人才项目(编号:Q20141308);国家自然科学基金项目(编号:41273066);青海省治多县乌丽地区天然气水合物调查项目联合资助

摘　　要：为查明青藏高原乌丽冻土区是否存在天然气水合物以及弄清天然气水合物气源,在对该区可能的烃源岩样品有机碳含量、岩石热解、镜质体反射率测定等分析基础上,结合分子生物标志化合物分析技术,对乌丽地区二叠系和三叠系泥岩、炭质泥岩和煤进行了有机质来源、沉积环境以及热演化程度等方面的初步研究。结果表明,该区烃源岩发育于还原的海陆交互相沉积环境,有机质母质为低等水生生物输入与陆源高等植物的混合生源输入,部分样品低等水生生物来源占优势;除个别样品外,甾烷异构化参数和升藿烷异构化参数达到平衡点。上二叠统那义雄组部分泥岩层段有机碳含量较高且含煤层段较厚,处于过成熟热演化阶段,其可能为研究区内较好的气源岩;而上三叠统巴贡组仅在八十五道班西为含煤地层,分布范围有限,可能仅为局部气源。In order to ascertain whether there exists natural gas hydrate in Wuli premofrost of Tibet Plateau and to investigate the gas source of gas hydrate, based on the analysis of organic carbon content, rock pyrol ysis and vitrinite reflectance measurement on the potential source rocks and combined with molecular biomarker analysis technology,a preliminary study on organic sources,depositional environment and the thermal evolution degree was made on the Permian and Triassic mudstones,carbonaceous mudstones and coals from Wuli area. The results illustrated that the potential source rocks of this area were developed in reducing environment of marine-terrigenous facies,and most organic material was a mixture of lower aquatic organism and higher terrigenous plants. However, hiogensis of some samples was mainly originated from lower hydrobiont. The isomerization parameter values of C29 steranes and C32 homohopanes reached equilibrium point except individual sample. The organic carbon content in some mudstone intervals of Nayixiong Formation was relatively high and the coal-bearing sequence was relatively thick in the Upper Permian. and generally at over-mature stage. Therefore, they could he as gas source rocks. However, because of limited distribution in the west of eighty-five track section, the coal bearing strata of the Upper Triassic Bagong Formation might merely be local gas source.

关 键 词：烃源岩 地球化学特征 生物标志化合物 乌丽冻土区 青藏高原 

分 类 号：TE122.113[石油与天然气工程—油气勘探]