鄂尔多斯盆地黄陵—铜川地区延安组煤矿原油成因  

Origin of Crude Oil From Coal Mine of Yan’an Formation in Huangling-Tongchuan Area,Ordos Basin

作　　者：孔令印 李剑锋[1,2] 吴凯 马军[1,2] KONG Lingyin;LI Jianfeng;WU Kai;MA Jun(PetroChina Changqing Oilfield Company,Research Institute of Exploration and Development,Xi’an,Shaanxi 710018,China;PetroChina Changqing Oilfield Company,National Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields,Xi’an,Shaanxi 710018,China)

机构地区：[1]中国石油长庆油田分公司勘探开发研究院,西安710018 [2]中国石油长庆油田分公司低渗透油气田勘探开发国家工程实验室,西安710018

出　　处：《新疆石油地质》2024年第1期35-46,共12页Xinjiang Petroleum Geology

基　　金：国家科技重大专项(2016ZX05046-005)。

摘　　要：为明确鄂尔多斯盆地东南部黄陵—铜川地区延安组煤矿原油的地球化学特征及其成因,利用气相色谱、色谱质谱和同位素质谱技术,对研究区原油、煤岩和泥岩抽提物进行了生物标志化合物组成以及正构烷烃单体碳同位素分布特征的对比研究。煤矿原油姥鲛烷和植烷均势,倍半萜含量丰富,Ts/Tm、C_(29)Ts/C_(29)降藿烷相对较高,C_(30)莫烷/C_(30)藿烷、C_(29)降藿烷/C_(30)藿烷、C_(31)升藿烷及C_(32)升藿烷的22S/(22S+22R)相对较低,ααα-20R规则甾烷呈“V”字形分布,碳同位素及正构烷烃单体碳同位素偏轻;侏罗系煤系烃源岩抽提物中Pr/Ph高,倍半萜含量较低、Ts/Tm、C_(29)Ts/C_(29)降藿烷低,C_(30)莫烷/C_(30)藿烷、C_(29)降藿烷/C_(30)藿烷、C_(31)升藿烷及C_(32)升藿烷的22S/(22S+22R)高,ααα-20R规则甾烷呈倒“L”字形分布,碳同位素及正构烷烃单体碳同位素偏重。原油特征与煤系潜在烃源岩存在明显的差异,与盆地内长7段深湖亚相烃源岩及其生成烃一致。侏罗系延安组煤处于低成熟阶段,所生成的液态烃不能完全满足自身吸附的需要,不具备排出液态烃的能力,铜川崔家沟煤矿和黄陵店头煤矿原油均来源于下伏的长7段烃源岩。To clarify the geochemical characteristics and origin of the crude oil from the coal mine in Yan’an formation in Huangling-Tongchuan area,southeastern Ordos basin,a comparative study was conducted on the biomarker compositions and carbon isotope distribution of n⁃alkane monomers in extracts from crude oil,coal,and mudstone in the study area using gas chromatography,chromatography⁃mass spectrometry,and isotope mass spectrometry techniques.The oil from coal mine is characterized by equilibration of pristane and phytane,high sesquiterpene content,relatively high Ts/Tm and C_(29)Ts/C_(29)norhopane ratios,relatively low ratios of C_(30)moretane/C_(30)hopance,C_(30)norhopane/C_(30)hopance,and 22S/(22S+22R)for C_(31)homohopane and C_(32)homohopane,“V”⁃shaped distribution ofααα⁃20R regular sterane,and relatively light carbon isotopic values of crude oil and n⁃alkane monomers.The extracts from the Jurassic coal⁃bearing source rocks exhibit high Pr/Ph ratio,low sesquiterpene content,low Ts/Tm and C_(29)Ts/C_(29)norhopane ratios,relatively high ratios of C_(30)moretane/C_(30)hopance,C_(30)norhopane/C_(30)hopance,and high 22S/(22S+22R)values for C_(31)homohopane and C_(32)homohopane,inverted“L”⁃shaped distribution ofααα⁃20R regular sterane,and relatively heavy carbon isotopic values of crude oil and n⁃alkane monomers.The characteristics of crude oil significantly differ from those of the potential coal⁃bearing source rocks,which is consistent with the deep lacustrine source rocks and the generated hydrocarbons of Chang 7 member in the basin.The coal of the Jurassic Yan’an formation is at a low maturity stage,and it is incapable of expelling liquid hydrocarbons,since the generated liquid hydrocarbons cannot even fully meet its adsorption needs.The crude oils in the Cuijiagou Coal Mine in Tongchuan and the Diantou Coal Mine in Huangling are both originated from the source rocks of the underlying Chang 7 member.

关 键 词：鄂尔多斯盆地 黄陵—铜川地区 侏罗系 延安组 煤矿 原油 成因 

分 类 号：TE122.1[石油与天然气工程—油气勘探]