柴达木盆地西北部原油芳烃分子标志化合物分布特征及意义  

Distribution characteristics and significance of the aromatic hydrocarbons molecular biomarker in crude oil from the northwestern Qaidam Basin

作　　者：蒙炳坤 周世新 李靖 陈克非 张臣 李朋朋 孙泽祥 MENG Bing-kun;ZHOU Shi-xin;LI Jing;CHEN Ke-fei;ZHANG Chen;LI Peng-Peng;SUN Ze-xiang(Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;Key Laboratory of Petroleum Resources Research,Gansu Province,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院西北生态环境资源研究院,甘肃兰州730000 [2]甘肃省油气资源研究重点实验室,甘肃兰州730000 [3]中国科学院大学,北京100049

出　　处：《天然气地球科学》2021年第5期738-753,共16页Natural Gas Geoscience

基　　金：国家科技重大专项(编号:2016ZX05003-002-004);国家自然科学基金项目(编号:41072105,41872147)联合资助.

摘　　要：为了明确柴达木盆地西北部(简称"柴西北")原油的有机质来源、成熟度和沉积环境等,进而认识柴西北原油的成因和富集规律,对柴西北小梁山凹陷和茫崖凹陷古近系—新近系储层来源的41件原油的饱和烃和芳香烃进行了系统分析。根据柴西北小梁山凹陷和茫崖凹陷古近系和新近系储层原油芳香烃化合物分布特征,原油总体上被划分为2类:第一类原油,芳烃化合物以三芳甾烷系列的相对含量最高,萘系列、菲系列、三芴系列和?系列化合物相对含量次之;第二类原油,芳烃化合物以菲系列的相对含量最高,萘系列、三芴系列、三芳甾烷系列和?系列化合物相对含量次之。饱和烃和芳香烃中指示有机质来源、沉积环境和成熟度的分子标志物分布特征表明,柴西北小梁山凹陷和茫崖凹陷古近系—新近系储层原油属于半咸水—咸水湖相原油,以低等水生生物输入为主,陆源高等植物输入为辅,原油均处于成熟的演化阶段,该地区古近系—新近系主力烃源岩沉积期的水体具有较强分层程度和还原性。在柴西北小梁山凹陷和茫崖凹陷中,从西北到东南,不同构造带古近系—新近系主力烃源岩沉积期的水体分层程度依次变差,还原性依次降低,成熟度依次升高,表明该地区古近系—新近系储层油气具有近源成藏的特征,靠近阿尔金山的红沟子、小梁山、咸东和咸水泉构造带是今后原油勘探重要领域,而处于小梁山凹陷和茫崖凹陷斜坡区的油泉子、南翼山、大风山、黄瓜茆和开特米里克构造带是今后原油和天然气勘探的重要领域。In order to clarify the organic matter source,maturity and depositional environment of crude oil in the northwestern Qaidam Basin,studies are carried out to better understand the genesis and accumulation pattern of crude oil in the northwestern Qaidam Basin. Systematic analyses were performed on 41 saturated hydrocarbons and aromatic hydrocarbons of crude oil in the Paleogene and Neogene reservoirs of the Xiaoliangshan Depression and Mangya Depression of the northwestern Qaidam Basin. According to the distribution characteristics of the aromatic compounds of Paleogene and Neogene reservoirs crude oil in Xiaoliangshan Depression and Mangya Depression of northwestern Qaidam Basin,crude oil is generally divided into two groups. In the first type of crude oil,the relative content of aromatic compounds is the highest in the triaromatic steroid series,followed by the relative content of the naphthalene series,phenanthrene series,trifluorene series,and the chrysene series.In the second type of crude oil,phenanthrene series have the highest relative content of aromatic compounds,followed by the relative content of naphthalene series,trifluorene series,triaromatic steroid series,and chrysene series. The distribution characteristics of molecular biomarkers in the saturated hydrocarbon and aromatic hydrocarbon which implies the source of organic matter,depositional environment and maturity indicate that the Paleogene and Neogene reservoirs crude oils from Xiaoliangshan Depression and Mangya Depression of the northwestern Qaidam Basin belong to light brackish-brackish lacustrine oil,and are in the mature stage of evolution,dominated by low aquatic organisms,supplemented by terrestrial higher plants. The water bodies of the main source rocks of the Paleogene-Neogene in this area have a strong stratification degree and reduction. In the Xiaoliangshan Depression and Mangya Depression of the northwestern Qaidam Basin,from the northwest to the southeast,the stratification of water in the main source rocks of different tectonic be

关 键 词：小梁山凹陷 茫崖凹陷 饱和烃 芳香烃 母质类型 沉积环境 成熟度 

分 类 号：TE122.1[石油与天然气工程—油气勘探]