渤海湾盆地沾化凹陷渤南洼陷原油地球化学特征及成藏期分析

THE GEOCHEMISTRY CHARACTERISTICS AND ACCUMULATION-HISTORY OF CRUDE OIL IN THE BONAN SUB-SAG OF THE ZHANHUA SAG, THE BOHAIWAN BASIN

张枝焕 曾艳涛 张学军 袁东山 徐兴友

Zhang Zhihuan Zeng Yantao Zhang Xuejun Yuan Dongshan Xu Xingyou

石油大学, 石油天然气成藏机理教育部重点实验室, 北京, 102200 2. 中国石油化工股份有限公司, 胜利油田股份公司, 山东, 东营, 257000

Key Laboratory for Hydrocarbon Accumulation Mechanism, Ministry of Education, University of Petroleum, Beijing 102200, China 2. Shengli Oilfield, SINOPEC, Dongying, Shandong 257000, China

下第三系沙四段是沾化凹陷渤南洼陷深层主要产油层,目前关于沙四段原油的油源和成藏期问题还存在不同的认识。通过对研究区储层流体包裹体分析,结合沙四段原油的地球化学特征,沙三段和沙四段烃源岩的生、排烃资料及构造演化资料,讨论了沙四段油藏的形成历史。研究表明,渤南洼陷沙四段曾发生过2期油气充注:第一期始于沙二段沉积末期,主要时期为沙一段沉积后期到东营组沉积中期,由于构造抬升,至东营组沉积末期(28.8 Ma)可能存在间断;第二期油气聚集从馆陶组沉积初期到明化镇组沉积早期,主要在馆陶组沉积期。油气成藏时期与沙四段和沙三段烃源岩的主要生、排烃期是相一致的。由此推测,沙三段与沙四段油源的相对贡献主要取决于烃源岩与油源断层及圈闭的空间配置关系。

The 4th member of the Shahejie Formation is the main petroleum reservoir in the Bonan sub-sag,the Zhanhua sag.At present,there are some different points of view about the distribution of the source rocks contributing to this reservoir and the history of hydrocarbon accumulation.According to some geological or geochemical data in the region of interest,including the homogenization temperature of fluid inclusion,the geochemistry characteristics of crude oil,periods of hydrocarbon generation and expulsion in source rocks of the 3th member and the 4th member of the Shahejie Formation,and the evolution of faul-tage,the history of hydrocarbon accumulation in the 4th member of the Sahejie Formation are discussed in this paper.The result shows that the process of petroleum accumulation in the 4th member of the Shahejie Formation is divided into two major phases.The first stage of the accumulation process started at the late stage of Es2,mainly from the middle period of Es2 to the metaphase of Ed.The second stage was from the initial stage of Ng to the initial stage of Nm,mainly at the middle-late stage of Ng.The process of petro-leum accumulation was discontinuous in the late stage of Ed because of the uplift of stratum in that period.The periods of petroleum accumulation are in consonance with the period of hydrocarbon generation and expulsion in source rocks of the 3th member and the 4th member of the Shahejie Formation.Therefore,it is suggested that the relative contribution of the source rocks of the 3th member and the 4th member of the Shahejie Formation to formation of reservoir mainly depend on the spacial relation between source bed and fault or trap.

国家十五重点科技攻关课题(2001BA605A09)

https://doi.org/10.11781/sysydz200601054