冀北坳陷双洞背斜铁岭组沥青的有机地球化学特征及其地质意义  

Organic geochemical characteristics and the geological significance of bitumen from Tieling Formation of Shuangdong Anticline in North Hebei Depression

作　　者：宋到福[1] 王铁冠[1] 张迈 唐友军 陈媛 SONG Daofu;WANG Tieguan;ZHANG Mai;TANG Youjun;CHEN Yuan(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249;College of Resources and Environment,Yangtze University,Wuhan 430100,Hubei;Wuxi Research Institute of Petroleum Geology,Petroleum Exploration and Production Research Institute,SINOPEC,Wuxi 214126,Jiangsu)

机构地区：[1]油气资源与探测国家重点实验室(中国石油大学(北京)),北京102249 [2]长江大学资源与环境学院,湖北武汉430100 [3]中国石化石油勘探开发研究院无锡石油地质研究所,江苏无锡214126

出　　处：《长江大学学报（自然科学版）》2021年第1期1-10,共10页Journal of Yangtze University(Natural Science Edition)

基　　金：国家重点研发计划项目“超深层及中新元古界油气资源形成保持机制与分布预测”(2017YFC0603102)。

摘　　要：冀北坳陷双洞背斜铁岭组沥青样品是活油苗沿裂隙运移到地表后,在低温蚀变作用下形成的,未经高温蚀变,因而其有机地球化学信息丰富,能很好地反映沉积有机质原始地质信息。所分析的沥青样品中检测到了高丰度的13α(正烷基)三环萜系列、补身烷系列(包括长链的补身烷系列)、规则藿烷系列、25-降藿烷及8,14-断藿烷,未检测到甾类化合物,其中13α(正烷基)三环萜类是元古界沉积有机质中特有的一类生物标志化合物,其具体生源尚不明确。沥青样品中甾类化合物的缺失以及丰富规则藿烷类化合物的检出表明原核菌藻类生物应该是双洞背斜铁岭组沥青的主要生源;高丰度25-降藿烷和8,14-断藿烷系列的出现指示生物降解作用是导致沥青形成的重要因素之一。冀北坳陷沉积埋藏史、生烃史以及沥青样品中高丰度的13α(正烷基)三环萜类均证实,洪水庄组泥质岩应为双洞背斜铁岭组沥青的主要烃源岩。Bitumen samples from the Tieling Formation of Shuangdong Anticline in the North Hebei Depression were formed by low-temperature alteration after living oil-seedlings migrated to the surface along the fractures.Without high-temperature alteration,therefore,their organic geochemical information is abundant,which can well reflect the original geological information of sedimentary organic matter.The high abundance of 13α(n-alkyl)tricyclic terpenes,drimanes(including long-chain drimanes),regular hopanes,25-norhopanes and 8,14-secohopanes were detected in the bitumen samples analyzed,with an absence of steranes.Among them,13α(n-alkyl)tricyclic terpenes are a special class of biomarkers in proterozoic sedimentary organic matter,whose origin is not clear yet.The absence of steranes in bitumen samples and the detection of abundant steranes indicate that prokaryotic algae organisms should be the main source of bitumen from Tieling Formation of Shuangdong Anticline.The emergence of high abundance of 25-norhopanes and 8,14-secohopanes indicates that biodegradation is one of the important factors leading to the formation of the bitumens.The sedimentary and burial history,hydrocarbon generation history and the high abundance of 13α(n-alkyl)tricyclic terpanes in the bitumen samples in the North Hebei Depression all confirm that the argillaceous rocks of Hongshuizhuang Formation should be the main source rocks of the bitumen from Tieling Formation in Shuangdong Anticline.

关 键 词：冀北坳陷 双洞背斜 沥青 有机地球化学 生物标志物 烃源岩 

分 类 号：P618.13[天文地球—矿床学]