石油与天然气地质2025，Vol.46Issue(2)：377-391,15.DOI:10.11743/ogg20250204
渤海湾盆地东濮凹陷洼陷带油气地质新认识与勘探突破
New insights and exploration breakthroughs in hydrocarbon exploration in sub-sag zones of the Dongpu Sag,Bohai Bay Basin
摘要
Abstract
Over more than four decades of hydrocarbon exploration in the Dongpu Sag within the Bohai Bay Basin,the sub-sag zones,critical targets for hydrocarbon exploration,have accounted for 49%of the total exploration area.However,their proven geological reserves constitute only 1%of the total,highlighting an exploration dilemma characterized by abundant residual hydrocarbon resources,low proven geological reserves,limited oil production despite tested oil flow,and difficulties in expanding the development of discovered hydrocarbon resources.Based on the increasingly intensive investigation of hydrocarbon enrichment patterns in recent years,we systematically explore the source rocks,source rock-reservoir configurations,and hydrocarbon accumulation sequences in different types of sub-sags within the Dongpu Sag while integrating various data from core observation,logging,analyses,and laboratory tests.The results indicate that:① effective source rocks with relatively small thicknesses and high organic matter abundance(TOC content>1%)serve as the major source rocks in the sub-sag zones.This finding challenges the traditional understanding that source rocks are widely developed in sub-sags,facilitating the delineation of exploration targets;② High-frequency lake-level fluctuations have resulted in a unique sedimentary rhythm of alternating sandstone and mudstone layers.The vertical superimposition of effective source rocks and sand bodies,along with the contiguous distribution of reservoirs near sub-sags,overturns the traditional view that sub-sags contain well-developed mudstones while lacking well-developed reservoirs;③ Hydrocarbon charging and fluid overpressure are identified as the dominant factors governing the formation of reservoirs near sub-sags,significantly extending the lower depth limit of effective reservoirs.This challenges the long-standing perception that the so-called"death boundary"for the formation of effective reservoirs in continental clastic rocks is 3 500 m;④ Additionally,hydrocarbon reservoirs in the sub-sag zones feature sequential hydrocarbon accumulation,contradicting the traditional belief that no hydrocarbon reservoirs occur below aquifers.Based on these insights,exploration breakthroughs have been achieved,including high-yield hydrocarbon flow exceeding 100 m3 oil-gas valent weight on a daily basis in the Gegangji Sub-sag,kilometer-thick oil-bearing intervals in the southwestern sub-sag zone,and the shale/tight oil resources at the hundred-million-ton level in the Qianliyuan Sub-sag.These achievements have driven the strategic shift in hydrocarbon exploration from tectonic zones to sub-sag zones in the Dongpu Sag,facilitating the delineation of exploration targets for large-scale reserve growth.The results of this study provide valuable guidance for hydrocarbon exploration in sub-sag zones within the Bohai Bay Basin.关键词
高效源岩/有效储层/接续成藏/洼陷带/东濮凹陷/渤海湾盆地Key words
efficient source rock/effective reservoir/sequential hydrocarbon accumulation/sub-sag zone/Dongpu Sag/Bohai Bay Basin分类
能源科技引用本文复制引用
段金宝,徐田武,杨栋栋,姜振学,高永涛,王德波,李路,袁波..渤海湾盆地东濮凹陷洼陷带油气地质新认识与勘探突破[J].石油与天然气地质,2025,46(2):377-391,15.基金项目
新型油气勘探开发国家科技重大专项(2024ZD1400101) （2024ZD1400101）
中国石化科技部项目(P25032). （P25032）
