车西洼陷油气倒灌运移成藏条件研究

The Study of Reservoir Forming Conditions about HC Migration Downward in Chexi Sag

向立宏 王学军 郝雪峰 李晓燕

XIANG Lihong WANG Xuejun HAO Xuefeng LI Xiaoyan

中国石油化工股份有限公司胜利油田分公司地质科学研究院, 山东东营 257015

Geoscience Research Institute of SINOPEC Shengli Oilfield Company, Dongying Shandong 257015, China

车西洼陷位于渤海湾盆地南部,是济阳坳陷西北部次级构造单元。针对该区沙四上亚段油气倒灌运移成藏现象及成藏机理,从基本地质特征分析入手,结合油源对比、有效烃源岩展布特征、储盖配置关系、成藏动力、输导体系等几方面研究,认为沙三段烃源岩为本区有效烃源岩,源下沙四上亚段油藏为沙三段源岩生气的油气向下倒灌运移成藏。"源上厚泥封盖、源中超压下注、源下隐蔽输导优相成藏"是本区油气倒灌运移成藏的主要成藏条件。油气倒灌距离与源岩剩余压力具有一定的正相关关系,物性条件控制源下储层含油性。上述观点进一步完善了济阳坳陷油气成藏理论认识,对渤海湾盆地勘探实践具有现实的借鉴意义。

Chexi sag is located in the south of Bohai Bay, it is a secondary tectonic unit of Jiyang depression. In this paper, the mech-anism of HC migration downward has been studied on the basis of the analyzing results about the geologic characteristic combined with oil-source correlation, the distribution of effective source rock, allocation of source, reservoir and cap rock, reservoir forming dynamic and conduit system. The study results indicate that the source of Es3 is effective source rock in Chexi Sag, and the oil from source of Es3 migrated downward to the reservoir of Es4. It is considered that the main HC accumulating conditions are mud seals over source rocks, oil and gas migration downwards into reservoir under the oil source by overpressure of the oil source beds, and the good transmission system under source rocks are the better is the physical characteristic of reservoirs, the more easy the oil formed. There is a positive correlation between the downward HC migration distance and the overpressure of the oil source bed. Physical characteristic of reservoirs controlled the HC existence of reservoirs. The above concepts improve knowledge of hydrocarbon accu-mulation theory of Jiyang depression. It can be used for guiding the HC exploration in Bohai Bay.

国家油气重大专项《渤海湾盆地精细勘探关键技术》课题三"济阳坳陷油气富集机制与增储领域"(2011zx05006)资助。

https://doi.org/10.3969/j.issn.1008-2336.2013.02.042