东营凹陷北部陡坡带隐蔽油气藏的形成与分布

东营凹陷北部陡坡带不同时期发育了不同类型的隐蔽油气藏,断陷期主要形成各种类型岩性及与之相关的复合油藏,主要包括透镜体油藏、构造-岩性油藏、上翘尖灭油藏、物性油藏;断-坳过渡期形成了以地层油藏为主及与地层控制因素有关的岩性和构造油藏,主要包括地层不整合、断层-岩性油藏、地层超覆-断层油气藏、受地层不整合控制的断层-岩性油藏及地层油藏。不同的隐蔽油气藏聚集了不同类型的油气,北部陡坡带外围断陷期形成的受构造控制的沙河街组三段地层-岩性油藏、断-坳过渡期形成的以地层为主的圈闭中主要聚集源自沙河街组四段烃源岩的油气;内侧靠近生油中心的沙河街组三段透镜体岩性及其他与岩性相关的油藏、沙河街组三段上部断层-岩性等油藏主要聚集源自沙河街组三段烃源岩的油气。北部陡坡带隐蔽油气藏的形成与油气分布特征受控于古构造背景、油气疏导体系、生储盖组合及成烃与成藏要素的有机配置等多种因素。

Formation and distribution of subtle reservoirs in northern steep slope zone of Dongying depression

Various types of subtle reservoirs are developed in the northern steep slope zone of Dongying depression during different periods. During fault subsidence, various lithologic reservoirs and relevant compound reservoirs, including lenticular reservoirs, structural-lithologic reservoirs and updip pinch out reservoirs, are developed. During the transitional period from fault subsidence to downwarping, stratigraphic reservoirs as well as lithologic and structural reservoirs controlled by stratigraphy are developed, including unconformity reservoirs, fault-lithologic reservoirs, strati-graphic overlap-fault reservoirs, and fault-lithologic and stratigraphic reservoirs controlled by unconformities. Various types of hydrocarbons accumulated in different subtle reservoirs. On the periphery of the northern steep slope zone, hydrocarbons accumulated in the structure-controlled stratigraphic-lithologic reservoirs in the 3rd member of Shahejie Formation that have been formed during fault subsidence period, and in the stratigraphic reservoirs formed during the transitional period from fault subsidence to downwarping have mainly been sourced from the 4 member of Shahejie Formation. While in the inner part near hydrocarbon-generating center, hydrocarbons accumulated in the lenticular lithologic reservoirs and other lithology-related reservoirs in the 3rd member of Shahejie Formation, and fault-lithologic reservoirs in the upper part of the 3rd member of Shahejie Formation have mainly been sourced by the source rocks in the 3rd member of Shahejie Formation. The formation of subtle reservoirs and the distributional characteristics of petroleum have been controlled by various factors, such as paleo-tectonic setting, hydrocarbon migration pathways, combination of source, reservoir and cap rocks, and the timing of hydrocarbon generation and accumulation.