金湖凹陷西斜坡阜宁期构造-沉积演化与油气聚集

Tectonic-sedimentary evolution and hydrocarbon accumulation during the Funingian on the western slope of the Jinhu depression,northern Jiangsu

金湖凹陷西斜坡为苏北盆地东台坳陷西部的一个次级构造单元,构造运动控制了斜坡的形成、演化、沉积物的充填模式及斜坡内各种沉积体系的发育和空间展布,进而影响油气的生成、运移和聚集。本文应用平衡剖面技术,编制了金湖凹陷西斜坡阜宁期构造演化剖面;应用厚度分析法,研究了阜宁期断层活动强度。通过对研究区取心井的岩心观察、描述,结合录井、测井及地震资料,分析了阜宁组的沉积相类型及分布特征,查明了金湖凹陷西斜坡的构造-沉积演化特征及其对油气分布的影响。认为油气主要围绕深凹带或次凹带呈半环带状分布。西斜坡上发育的一系列北北西向构造带具有良好的构造、沉积背景,是斜坡带上油气成藏的优选区。

The western slope of the Jinhu depression,northern Jiangsu appears as a secondary tectonic unit in the western part of the Dongtai depression in the North Jiangsu Basin. The tectonic movements herein are believed to exercise a major control on the formation,development and evolution of the slope; filling processes and filling patterns of the sediments; development and spatial arrangement of individual depositional systems within the slope, and thus generation,migration and enrichment of hydrocarbons. The emphasis in the present paper is placed upon the construction of the Funingian structural evolutionary section with the aid of balanced section technique; the intensity of the Funingian faulting in terms of the thickness analysis; sedimentary facies types and distribution in the Funing Formation,and tectonic-sedimentary evolution and its effects on hydrocarbon accumulation on the western slope of the Jinhu depression on the basis of core observation and description,well logs and seismic data. The hydrocarbons are mainly accumulated in a semigirdle shape around the deeper depressed zones or secondary depressed zones. A number of NNW-trending structural belts are considered as the favourable areas for hydrocarbon accumulation on the western slope of the Jinhu depression.