南黄海盆地北部坳陷古近系沉积特征及其沉积演化

南黄海盆地经历了多年油气勘探,无论是在中生界还是新生界,至今未获得油气突破。新生界储层具有优越的储集条件,故重点分析了古近系阜宁组和三朵—戴南组的沉积特征及其沉积演化特征。以钻井和测井资料为基础,将阜宁组和三朵—戴南组划分为4种沉积相类型,即河流相、扇三角洲相、三角洲相和湖相,其中河流相在研究区可划分为辫状河流相和曲流河流相;并且分析了各沉积相、沉积亚相和沉积微型的岩电性特征。仔细解剖地震反射特征,进行阜宁组和三朵—戴南组地震相分析,以单井相分析为基础,解析各地震相沉积意义。根据瓦尔特定律,将单井沉积相分析与地震相分析充分结合,分析各层段沉积相分布特征。阜宁组主要发育曲流河流相、扇三角洲相、滨浅湖相和半深湖相;三朵—戴南组主要发育辫状河流相、扇三角洲相和滨浅湖相。根据区域构造演化特征,结合沉积相分析,深入分析了研究区古近系阜宁组至三朵—戴南组的沉积演化特征。

SEDIMENTARY CHARACTERISTICS AND EVOLUTION OF THE PALEOGENE IN THE NORTHERN DEPRESSION OF THE SOUTH YELLOW SEA BASIN

No breakthrough has been gained in the Mesozoic and Cenozoic deposits in the South Yellow Sea Basin after years of oil and gas exploration.This paper is devoted to the sedimentary characteristics and evolutionary history of the Funing Formation and Sanduo-Dainan Formations of Paleogene.Drilling data,seismic data and well logging data suggest that the Funing Formation and Sanduo-Dainan Formations are mainly composed of four types of facies,i.e.fluvial facies,fan delta facies,deltaic facies and lacustrine facies,and the fluvial facies can be further divided into braided fluvial facies and meandering fluvial facies in the study area.Lithology and electrical properties of all the sedimentary facies,subfacies and mcrofacies are fully studied.Seismic facies are then established for the two Formations as the result.According to Walther＇s law,the spatial distribution pattern of facies is described based on well data and seismic data.Our results indicate that the Funing Formation is dominated by meandering river facies,fan delta facies,coastal and shallow lake facies and semi-deep lake facies;and the Sanduo-Dainan Formations dominated by braided fluvial facies,fan delta facies and nearshore lacustrine facies.Sedimentary evolutionary history is established through facies analysis and the study of tectonic background of the two formations.