文南油田沙一段油藏形成条件及分布规律

文南油田位于东濮凹陷中央隆起带南部，沙一段是现阶段该油田开发的主要接替层系，油藏类型属于岩性型和岩性一断块型。文南油田沙一段储集层位于烃源岩与盐岩之间，形成互层式自生自储自盖组合，由于大部分地区沙一段烃源岩刚进入生油门限，其原油多属于未熟一低熟油。文南油田沙一段的沉积相分布受继承性活动的水下古构造高地的控制，物源来自西南方向，发育三角洲一滩坝沉积体系，砂体向古高地方向尖灭，然后渐次向碳酸盐岩一盐岩过渡，盐岩相变带控制了岩性圈闭的分布，因此沙一段油藏与中原油田主力开发层系沙二段、沙三段油藏区别很大。图5参8

Formation and distribution of reservoir of Member 1 of Shahejie Formation, Wennan Oilfield

The Wennan Oilfield is located at the south central uplift belt, Dongpu Sag, where the reservoir of Member 1 of Shahejie Formation is the major super-seder and it is a lithologic and lithologic-fault block. The reservoir in Member 1 of Shahejie Formation developed between source rock and halite, forming inter-bed combination of self-generate, self-storage and self-cover. The oil is mainly immature because that the most source rock of Member 1 of Shahejie Formation entered the oil-window. The sedimentary facies of Member 1 of Shahejie Formation in the Wennan Oilfield is controlled by successive sub-aqueous palaeo-uplift and the source in the SW direction, and a delta-beach-bar system was developed. Sand pinched out to palaeo-heights and the transition from sand to carbonate and halite is gradual. The reservoir of Member 1 of Shahejie Formation in the Wennan Oilfield is obviously different from those of Member 2 and 3 of Shahejie Formation, which are the major reservoirs in the whole Zhongyuan Oilfield.