黄骅坳陷歧口凹陷隐蔽油气藏形成条件与分布规律

Discussion on the accumulation conditions and the distribution of the subtle traps in Qikou Sag, Huanghua Depression

歧口凹陷是黄骅坳陷隐蔽油气藏勘探的重点地区.本文分析了歧口凹陷隐蔽油气藏类型、形成条件,并得出隐蔽油气藏分布规律.该区的隐蔽油气藏成藏条件优越.隐蔽油气藏的类型主要有岩性油气藏、地层油气藏和复合油气藏三大类.该区的隐蔽油气藏主要分布在沙一下的颗粒灰岩储层及沙三段的滩坝砂体中.沙一段油藏的分布受灰岩小层及其尖灭线的控制;沙三段则受斜坡区滩坝砂体分布规律的控制.

Qikou Sag is the main region for the exploration of subtle traps in Huanghau Depression. The types and the accumulation conditions of the subtle traps in this region are analyzed, and the distribution of them is obtained. The subtle traps have favorable conditions for hydrocarbon accumulation. The discovered subtle traps can be divided into three sorts: lithologic traps, stratigraphic traps and lsopaleo-structure traps. The subtle traps are mainly distributed in the biolithite reservoirs in the lower part of the first member of Shahejie Formation (Es1) and the shoal sandstone in the third member of Shaheije Formation (Es3). The distribution of the subtle traps in the first member of Shahejie Formation (Es1) is controlled by the substrata of the biolithite and their pinching lines, and the distribution of the subtle traps in the third member of Shaheije Formation (Es3) is controlled by the distribution of the shoal sandbodies in slope zone.