摘要
黄骅坳陷发育了石炭-二叠系煤系烃源岩、古近系孔二段和沙三段暗色泥岩等3套有利烃源岩,导致原油成因及来源复杂多样.为进一步明确中-古生界原油成因与来源,在前人研究基础上明确了研究区3套烃源岩的生标化合物特征,并根据20个原油及油砂样品的碳同位素组成、生物标志化合物参数及饱和烃色谱和色-质谱图等特征,对研究区的原油成因类型进行划分并展开精细油源对比,认为黄骅坳陷南区围绕沧东-南皮凹陷分布的潜山是孔二段烃源岩生成油气的潜力分布区带;坳陷中北区沙三段烃源岩发育较好的潜山带,则是沙三段烃源岩生成油气的主要聚集区;而石炭-二叠系烃源岩生成原油则主要分布在新生代断裂不发育的褶皱潜山带,如乌马营潜山、孔西潜山等将是煤成油的有利勘探区带.研究结果表明:黄骅坳陷中-古生界原油可划分为3个大类6个亚类,且不同成因类型原油的分布特征受控于3套有效烃源岩的展布范围,其中I类原油主要源自石炭-二叠系煤系烃源岩,其碳同位素重于-28‰、三环萜烷含量高、Ts/Tm比值普遍低于1.0、C27-29甾烷呈"L"型分布,平面上分布范围局限,仅在孔西、乌马营等褶皱型潜山发育,且Ⅰ1类原油中混入了沙三段烃源岩贡献;Ⅱ类原油主要来自沙三段烃源岩,碳同位素较重、三环萜烷含量中等、Ts/Tm比值较小、C27-29甾烷呈近"Ⅴ"型分布,主要分布在坳陷中区的北大港潜山和歧北潜山,且Ⅱ2类原油中混入了石炭-二叠系烃源岩的贡献;而Ⅲ类则主要源自孔二段烃源岩,原油碳同位素轻于-30‰、三环萜烷含量低、Ts/Tm普遍大于1.0、C27-29甾烷呈反"L"型分布,仅分布在孔南地区,且Ⅲ1类原油中混入了少量的石炭-二叠系来源.
Three sets of favorable source rocks are developed in the Huanghua Sub-basin including the Carboniferous-Permian(C-P) coaly measure, the second member of Kongdian formation(Ek2) and the third member of Shahejie formation(Es3) in Paleogene, resulting in the complex genesis and source of crude oil. To further identify the origin and source of Meso-Paleozoic oil in the Huanghua Sub-basin, biomarker characteristics of the three sets of source rocks are identified firstly based on the previous research results. Genetic types of crude oil were classified on the basis of the carbon isotope, biomarker parameters and GC and GC-MS characteristics of 20 crude oil and oil sand samples, and then oil-source correlation was carried out meticulously combined with the actual geological background. It can be concluded that buried hills surrounding the Cangdong-Nanpi depression in the southern area are potential zones for crude oil source from Ek2 source rocks, while crude oils source from Es3 source rocks are mainly accumulated in the central-northern area where Es3 source rocks are well developed. And the crude oil source from C-P coaly source rocks are mainly distributed in the folded buried hills with undeveloped Cenozoic faults such as Wumaying and Kongxi buried hills, which can be favorable exploration zones for the coal-derived oil. The results show that crude oils of Meso-Paleozoic in the Huanghua Sub-basin were divided into 3 types and 6 sub-types using cluster analysis method according to their biomarker parameters. Overall, distributions of different types of oil are controlled by the areal extent of the 3 sets of effective source rocks. Specifically, type I crude oil with carbon isotope heavier than-28‰, higher content of tricyclic terpenes, Ts/Tm ratio lower than 1.0 and "L" type distribution of C27-29 regular sterane, is mainly sourced from C-P coaly measure source rocks and limitedly distributed in the Kongxi and Wumaying hurried hills, of which sub-type Ⅰ1 oil is mixed with the source of Es3 source rocks. While type Ⅱ crude oil with relatively heavier carbon isotope, moderate content of tricyclic terpenes, lower Ts/Tm ratio and near "Ⅴ" type distribution of C27-29 regular sterane, is mainly sourced from Es3 source rocks and distributed in the central part of the sub-basin including the Beidagang and Qibei hurried hills, of which sub-type Ⅱ2 oil is mixed with the contribution of C-P source rocks. And type Ⅲ crude oil with carbon isotope lighter than-30‰, low content of tricyclic terpenes, Ts/Tm ratio greater than 1.0 and reverse "L" type distribution of C27-29 regular sterane, is mainly sourced from Ek2 source rocks and distributed in the southern part of the sub-basin, of which sub-type Ⅲ1 oil is mixed with the contribution of C-P source rocks.
作者
吕雪莹
蒋有录
姜文亚
李宏军
刘景东
LYU Xueying;JIANG Youlu;JIANG Wenya;LI Hongjun;LIU Jingdong(School of Geosciences,China University of Petroleum(East China),Qingdao,Shandong 266580,China;Exploration&Development Research Institute,PetroChina Dagang Oilfield Company,Tianjin 300280,China)
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2019年第6期1290-1300,共11页
Journal of China University of Mining & Technology
基金
国家重大科技专项(2016ZX05006-007)
关键词
黄骅坳陷
中-古生界
聚类分析
成因类型
油源对比
Huanghua Sub-Basin
Meso-Paleozoic
cluser analysis
genetic type
oil-source correlation
