苏北盆地东台拗陷新生代地层地震地层学初步应用

A PRELIMINARY APPLICATION OF SEISMIC STRATIGRAPHY TO THE CENOZOICS OF DONGTAI DOWNWARP,NORTH JIANGSV BASIN

江苏省第六物探大队

The 6th Geophysical Exploration Brigade of Jiangsu

地层岩性油气藏是苏北盆地寻找新生代非构造圈闭油气藏的一种重要类型。文章利用地震地层学的概念,对苏北陆相沉积盆地的新生代地层作了初步应用。1.根据削蚀、顶超、上超、下超标志对苏北盆地东台拗陷新生界进行地震层序的划分和沉积特征的分析。2.对东台拗陷各凹陷整个新生代时期的水体变化作了初步探讨;虽属陆相盆地,其水体升降基本可与全球性海平面升降相对比。3.对各凹陷的阜宁组、戴南组、三垛组地层的主要地震相进行分析和解释,指出浊流河道、三角洲、水下冲积扇、礁滩、地层岩性尖灭和砂岩透镜体的发育。4.明确古水系的分布、流向和沉积相的纵横组合。并指出可能的几种油气藏类型。

Stratigraphic and lithologic oil and gas reservoirs are the chief non-structural trap of this type in the Cenozoics of the North Jiangsu Basin. This paper abopts the concept of seismic stratigraphy and applies it to the North Jiangsu continental sedimentary basin, involving the following foor aspects.1. To divide the seismic sequence and to analyse the depositional characteristics of the Cenozoics in the Dongtai Downwarp. This is based on erosional truncation, toplap, onlap, and downlap configurations.2. To deal with Cenozoic water level fluctuation of each depression in the Dongtai Downwarp. This eustatic change of water level is comparable with global eustatic sea level chaneg.3. To analyse and interpret the main seismic facies of the Funing Formation Dainan Formation and Sanduo Formation in each depression. An evaluation about turbidity channel, delta, underwater alluvial fan, biostrom beach, stratigraphic-lithologic thin out and the development of lenslike sand bodies is presented.4. To define the distribution and direction of paleodrainage systems, the longitudinal and transversal combinations of depositional faies. The possible types of oil and gas reservoirs are also discussed.