河南省濮阳地区古近系沙河街组沙三段盐岩特征及其与岩性油气藏的关系

东濮凹陷北部中央隆起带及其周边地区在古近系沙河街组沙三段由下向上依次发育三套盐岩，每一套盐岩又由若干个盐岩韵律组成，盐岩韵律由盐岩（或膏岩）和泥岩构成。不同的盐岩韵律、同一盐岩韵律在不同地区厚度差异很大。盐岩的构造类型主要有原生板状盐岩构造、次生盐岩墙构造和后生变形盐岩构造。由于盐岩层极其致密，其阻隔作用使其下部地层的地层温度和地层压力均较高，有利于下覆生油岩中的有机质向油气转化；同时，在高温、高压下盐岩呈塑性状态，因此，又是良好的盖层。盐岩与砂泥岩相变，加之与构造配合形成一定规模的与盐岩有关的岩性油气藏，扩大了油气勘探的领域。与盐岩分布有关的油气藏有四种类型：砂体尖灭油气藏、岩性-断层油气藏、断层-岩性油气藏、断背斜油气藏。本文以河南省濮阳地区古近系沙河街组沙三段为例，详细阐述了三套盐岩在研究区的分布特征及其与油气运聚的关系，对于寻找隐蔽油气藏及下步滚动勘探开发具有十分重要的意义。

Relationship between salt beds and oil and gas reservoir of the Shahejie Formation of Paleogene in Puyang area, Henan Province

There are four sets of salt beds in the Shahejie Formation of Paleogene in the central u plift belt and its vicinity in northern Dongpu Depression. Each set of salt beds consists of numerous salt rock rhythms that are composed of salt rock and mudstone. Three sets of salt beds in the Member 3 of Shahejie Formation are investigated in this paper. Thicknesses of different and same rhythmic units are very different in various regions. Salt beds have three major structures: primary tabular salt bed, secondary salt bed wall and post deforming salt bed. Because salt beds are very dense with excellent sealing, the pressure and temperature of the underlying strata are so high that organic materials under source rocks turn into oil and gas easily. Salt beds under high pressure and temperature are plastic and therefore are high-quality caprocks. Phase change from salt rock to sandstone and mudstone together with structural movement formed lithologic reservoirs relative to salt beds. There are four kinds of oil reservoir traps in relation to salt bed distribution: sandstone pinch-out reservoir, lithologic-fault reservoir, fault-lithologic reservoir and fault-anticline reservoir. This paper discussed the distribution of three sets of salt beds and their relation to oil and gas accumulation in the Member 3 of Shahejie Formation of Paleogene in Puyang area, Henan Province. It is important for the exploration of subtle oil and gas accumulation futhermore in this region.