渤海湾盆地不同级别不整合及其油气成藏规律

Different Orders of Unconformities and Their Oil-Gas Accumulations in Bohai Bay Basin

根据渤海湾盆地构造运动和层序地层学特征,阐述了与不整合面相关的地层圈闭发育和成藏特征。认为新近系与古近系之间和古近系与前新生界之间为两个一级不整合面,前者在凹陷陡坡带主要发育超覆圈闭油气藏,在缓坡带既发育超覆圈闭油气藏,又发育不整合面遮挡油气藏;后者在主要凸起或低突起部位发育潜山油气藏。古近系内部发育3个二级不整合、10个三级不整合,二级不整合面上下均发育地层油气藏;与三级不整合面相关的地层油气藏规模较小,但数量很多,是目前精细勘探的主要目标。通过在济阳坳陷的多年实践,发现了数量可观的上述地层油气藏,为"东部稳产"的能源战略作出了贡献。

Based on the characteristics of tectonic movement and sequence stratigraphy in Bohai Bay basin, the stratigraphic trap development and oil-gas accumulation related with unconformities are presented. It is suggested that there are two first-order unconformities in the basin, i.e. Neogene/Paleogene and Paleogene/Mz-Pz unconformities. The former contains overlap trap reservoir in the sag＇s steep slope belt, and both overlap trap and unconformable barrier reservoirs in the ramp belt, The latter contains the buried hill reservoirs in swell and sub-swell. In the Paleogene, there are three second-order and ten third-order unconformities, and the straligraphic reservoirs occur above and beneath the second-order unconformities, while the stratigraphie reservoirs related to the third-order unconformities appear in small scale and many numbers. Hence they are the main targets for recent fine exploration here. Through manyyear exploratory practices in Jiyang depression, numerous such stratigraphic reservoirs have been discovered, making great contributions to the energy strategy for keeping a stable production in eastern China.