渤海湾超级油盆构造演化及其烃源岩发育

Tectonic evolution and source rocks development of the super oil-rich Bohai Bay Basin, East China

综合运用渤海湾盆地新采集的高品质地震剖面以及最新的勘探成果资料,通过对各主要层系的地层分布、构造和古地理格局的分析,系统开展渤海湾盆地大地构造演化的动力学研究。结果表明,渤海湾盆地所处的华北克拉通位于古亚洲洋、特提斯洋和太平洋等3大构造体系域的交接地带,经历了不同期次、不同方向、不同性质构造旋回的交替叠加,主要经历5期盆地构造演化与沉积建造阶段,即中新元古代大陆裂陷槽、早古生代克拉通边缘坳陷碳酸盐岩建造、晚古生代海陆过渡相克拉通内坳陷、中生代陆内走滑-伸展构造和新生代陆内裂陷阶段。盆地的多旋回演化,特别是晚古生代以来所经历的海西、印支、燕山和喜马拉雅等多期挤压、走滑和伸展构造活动,控制了多套优质烃源岩发育、改造和保存,尤以上古生界石炭系—二叠系煤系烃源岩以及古近系世界级特优质湖相烃源岩最为重要,为超级富油气盆地的成藏提供了重要的烃源保障。

The Bohai Bay Basin,as a super oil-rich basin in the world,is characterized by cyclic evolution and complex regional tectonic stress field,and its lifecycle tectonic evolution controls the formation of regional source rocks.The main pre-Cenozoic stratigraphic system and lithological distribution are determined through geological mapping,and the dynamics of the pre-Cenozoic geotectonic evolution of the Bohai Bay Basin are investigated systematically using the newly acquired high-quality seismic data and the latest exploration results in the study area.The North China Craton where the Bohai Bay Basin is located in rests at the intersection of three tectonic domains:the Paleo-Asian Ocean,the Tethys Ocean,and the Pacific Ocean.It has experienced the alternation and superposition of tectonic cycles of different periods,directions and natures,and experienced five stages of the tectonic evolution and sedimentary building,i.e.Middle–Late Proterozoic continental rift trough,Early Paleozoic marginal-craton depression carbonate building,Late Paleozoic marine–continental transitional intracraton depression,Mesozoic intracontinental strike-slip–extensional tectonics,and Cenozoic intracontinental rifting.The cyclic evolution of the basin,especially the multi-stage compression,strike-slip and extensional tectonics processes in the Hercynian,Indosinian,Yanshan and Himalayan since the Late Paleozoic,controlled the development,reconstruction and preservation of several sets of high-quality source rocks,represented by the Late Paleozoic Carboniferous–Permian coal-measure source rocks and the Paleogene world-class extra-high-quality lacustrine source rocks,which provided an important guarantee for the hydrocarbon accumulation in the super oil-rich basin.