摘要
塔里木盆地塔中地区中上奥陶统碳酸盐岩台地边缘以发育良好的多种粒屑滩和生物礁组成的镶边沉积体系为特征.通过精细的单井相分析,识别出砂屑滩、砾屑滩、生屑滩以及鲕粒滩等,并且区分出3种不同类型的生物礁:①隐藻灰泥丘;②主要由枝状苔藓虫、海绵或(和)珊瑚建造的障积礁;③由石质海绵、托盘类、层孔虫、珊瑚、管孔藻等建造的骨架礁.在面向深水盆地的台缘外带,以发育中～高能粒屑滩和骨架礁组合为特征.在背靠开阔海台地的台缘内带,主要表现为中低能粒屑滩、隐藻灰泥丘以及障积礁的组合.这个台缘镶边沉积体系总体上沿塔中1号断层西侧呈北西一南东向长带状展布,长度100多公里,是本区重要的油气聚集带之一.储层质量台缘外带总体上优于台缘内带,其中骨架礁礁核和粒屑滩灰岩最好,礁间海和滩间海沉积物较差.
The margin of the carbonate platform of the Middle and Upper Ordovician, Tazhong area, Tarim Basin is characterized by a well-developed rimmed depositional system which consists of various types of grain banks and organic reefs. Through detailed study of sedimentary facies of individual wells, calcaren-aceous, calcirudytic, bioclastic, and oolitic banks have been recognized in this rimmed system. Three types of reefs have been distinguished in the platform margin: cryptalgal limemud mounds, baffling reefsmainly constructed by branching bryozoa, sponges and/or corals, and framework reefs built up by sponges, calathium, stromatopora, corals, solenopora and others. The outer belt of the platform margin facing the deep-water basin is characterized by development of the assemblage of moderate and high energy grain banks and framework reefs. The assemblage of moderate and low energy grain banks, cryptalgal limemud mounds, and baffling reefs mainly occurs within the inner belt of the platform margin . This rimmed system of platform margin is distributed along the western side of Tazhong No. 1 Fault striking NW-SE , and is a belt more than 100 kilometers in the length. It is an important belt of oil and gas accumulation in this area. As far as the carbonate reservoir quality within this rimmed system is concerned, the outer belt of the platform margin is generally better than the inner one. The limestone beds in banks and reef cores are best, but sediments of interreef and interbank seas are poor.
出处
《古地理学报》
CAS
CSCD
1999年第2期8-17,共10页
Journal of Palaeogeography：Chinese Edition
关键词
塔中地区
奥陶统
碳酸盐岩台地
镶边沉积体系
Tarim Basin, Middle and Upper Ordovician, carbonate platform, rimmed depositional system
