摘要
研究表明塔中志留系为陆表海碎屑潮坪沉积。从其沉积特点及古地理背景出发，结合古陆表海环境的水动力特点，建立起塔中地区志留系的陆表海碎屑潮坪沉积模式，认为它可分为三个微相：泥坪、砂泥坪和砂坪。部分泥坪和大部分砂泥坪发育在水下，砂坪的沉积水动力与现代的潮坪相比相对较弱。障壁岛沉积不发育，潮汐流和风暴流对碎屑搬运和改造起主要作用，砂坪和砂泥坪中潮汐水道沉积和风暴沉积发育。水进时垂向上发育向上变粗的沉积序列，砂体中广泛发育交错层理；水退时可形成大面积连续性好的砂体及分布面积广而稳定的泥坪。砂坪微相的一些水下高地存在可能成为有利储层的纯净的石英砂岩。塔中１１井实例说明此相模式在塔中志留系的研究中是适用的。
Studies showed that the Silurian sytem in the Tazhong area was deposited in an epicontinental sea tidal flat environment.Combined its depositional feature and setting with the hydrodynamic feature of epicontinental sea area,an epicontinental sea facies model of clastic deposits of the Silurian system in the Tazhong area is established.Furthermore,it can be subdivided into three microfacies:mud flat and mixed flat,and sand flat.Its facies is broad and stable,but there exist no barrier island deposits.Compared with the flat depositional facies nowadays,it is deposited in deeper water.part of the mud flat and most of the mixed flat develop under the water, the hydrodynamics of the sand flat is relatively weak.Tidal current and hurricane current mainly control the transportation and reconstruction of the clastics,so their deposits are popular,especially in the sand flat and mixed flat.A vertical coarsing upward sequence is present in the transgressive period and cross-bedding is common in the sandstone.In the retrogressive period,sandstones with good continuity and a stable mud flat are formed in a broad area.Near some of the underwater high land in the sand flat environment,there may exist purer quartz sandstones,which may be a good reservoir.As an example,the analysis of the Tazhong 11 well shows that it is suitable for the study on the Silurian system in the Tazhong area with this model.
出处
《沉积学报》
CAS
CSCD
北大核心
1997年第3期41-47,共7页
Acta Sedimentologica Sinica
基金
国家教委科研基金
关键词
陆表海
碎屑潮坪
盆地
志留系
沉积相模式
epicontinental sea clastic tidal flat facies model\ Silurian System\ Tazhong area
