渤海海域古近系隐蔽油气藏层序地层学特征

运用适合于陆相地层分析的高分辨率层序地层学理论分析了渤海海域古近系层序地层学特征.在渤海古近系可划分出4个长期基准面旋回和11个中期基准面旋回.渤海海域古近系隐蔽油气藏成藏要素与层序地层格架有着密切的关系,长期基准面旋回上升至下降的转换位置是优质烃源岩发育的位置,中期基准面旋回的上升半旋回早期和下降半旋回的晚期是砂体发育的位置,中期层序界面与层序界面附近的砂体是油气运移的良好通道,与长期活动的断层一起构成了渤海复杂的油气运移输导体系.渤海海域古近系有6种隐蔽油气藏类型,不同类型的隐蔽油气藏在层序中出现的位置可以预测的.以JZA气藏为例,简要分析了层序地层学在隐蔽油气藏勘探中的应用.

Sequence stratigraphic characteristics of subtle oil-gas pool in the Palaeogene of Bohai Sea area

The sequence stratigraphic characteristics of the Palaeogene in Bohai Sea area were analyzed by the high-resolution sequence stratigraphy theory.The Palaeogene in Bohai Sea area can be divided into four large scale cycles(LSC) and eleven middle scale cycles(MSC).There is a close relationship between the sequence stratigraphic framework and the pool-forming elements of the subtle oil-gas pool in the Palaeogene of Bohai Sea area.The transition point from the base level rising cycle(BLRC) to the base level falling cycle(BLFC) is the location for development of hydrocarbon source rock.The lower part of the BLRC and the upper part of the BLFC are the development locations of sandstone.The MSC boundary and the sand body near the boundary are the good pathways for hydrocarbon migration,which constitutes the complex hydrocarbon migration system in combination with the long-active fault systems.There are six kinds of subtle oil-gas pool in the Palaeogene of Bohai Sea area.These pools appeared in the sequence framework may be predicated.The JZA Gas Pool is taken as an example to briefly illuminate the sequence stratigraphic analysis applied to the exploration for subtle oil-gas pool.