川东南灯影组沉积相划分与研究

自1964年四川盆地在威远构造上震旦统灯影组地层中钻获威远气田以来,后经近半个世纪的勘探,至今尚无明显突破。本文以川东南地区上震旦统灯影组实测剖面和钻井岩芯观察为基础,结合岩石学、沉积学和构造地质等方法,对该地区沉积相、沉积微相和其碳酸盐台地沉积体系特征进行了综合分析,并进一步分析了沉积相平面展布及演化过程。研究区灯影组的亚相以局限台地相潮坪一泻湖相为主,夹台内滩相,微相则发育潮上带、潮间带、潮下带、泻湖、鲕粒滩和砂屑滩的沉积类型。通过单井相划分和联井剖面查明沉积微相在纵向上的变化,利用沉积微相平面分布图分析了研究区各沉积微相的平面分布特征。微相是控制储层发育的主要因素之一,各微相物性分析结果表明台内滩相储集物性最好,潮坪相次之,为今后寻找油气藏的优选部位。

The division and analysis of the favorable reservoir depositional facies of the dengying formation Upper-sinian in southeastern Sichuan Basin

Since weiyuan gas field was found in Upper Sinian dengying formation which is in weiyuan structure of Sichuan basin in 1964, it hasn't been apparent breakthrough after exploration in semicentury .The article is based on measured sections and drilling cores observation of Upper Sinian dengying formation, combined with methods of petrology, sedimentary and structure geology, to analyse facies, microfacies and other carbonate platform sedimentary system comprehensively, and analyses facies distribution pattern with evolution process further. The primary subfacies of dengying formation in study area is restricted platform facies and tidal-lagoon facies, with intra-platform shoal. Sedimentary type like Supratidal zone, intertidal zone, subtidal zone, lagoon, oolitic beach and sandy beach is developed in microfacies. Longitudinal changes in microfacies can be observed in single well and united well sections. The distribution characteristic of every microfacies is analysed by using microfacies distribution pattern. The analysis in property of microfacies show that the reservoir property of intraplatform shoal is the best, and the tidal zone takes the second place. These will be the prior position in reservoir.