孟加拉湾缅甸若开盆地上新统斜坡水道复合体沉积特征  

Sedimentary Characteristics of Pliocene Slope Channel Complexes in the Rakhine Basin,Offshore Myanmar

作　　者：孙辉[1] 范国章[1] 吕福亮[1] 徐志诚[1] 马宏霞[1] 

机构地区：[1]杭州地质研究院,杭州310023

出　　处：《沉积学报》2011年第4期695-703,共9页Acta Sedimentologica Sinica

摘　　要：斜坡水道复合体是孟加拉湾缅甸海上若开盆地上新统最重要深水沉积结构单元之一。研究工作以地震响应与深水储层之间的对应关系为指导,二、三维地震资料中的强振幅属性用以判断水道复合体内的粗粒沉积。利用多种地震技术,包括相干切片分析、地质异常体处理以及三维可视化,将斜坡水道复合体从背景中区分出来,并从斜坡水道复合体的外部几何形态、内部充填特征以及储层性质等方面进行了详细描述。研究区上新统内刻画出几期规模较大的加积型水道砂,沿着水流方向,水道砂在7～16 km范围内变化,宽度不超过10 km,垂向上由3～5个单砂层组成,单砂层之间彼此连通。加积斜坡水道复合体有望成为若开盆地最有利的勘探目标。Slope channel complex is one of the most important sedimentary architecture elements in Pliocene in Rakhine Basin,offshore Myanmar.This study is carried out under the guidance of the relationship between the seismic response and deepwater reservoir.The strong amplitude attributes on 2D and 3D seismic data are applied to deduce coarse sediment existing in slope channel complexes.Technologies that include coherence slice analysis,geoanomaly processing and 3D visualization are used for distinguishing slope channel complexes from background.Detailed descriptions,involving the external geometric shape,the nature of internal fill and reservoir characters are executed. Three kinds of slope channel complexes have been observed and identified based on the 3D seismic data.Multiple phase aggradational confined channel complexes have been detected in Pliocene in Rakhine Basin.Several large sand bodies,ranging from 7 km to 16 km in the down-current direction and usually no more than 10 km in width,have been indentified.These sands comprised 3～5 layers vertically and are related with each other. Channel complexes analysis and characterization in this research area result in the recognitions that the confined channel complexes with complicated shapes and sustainable change on morphology and packing characteristics downstream in lower Pliocene are developed.The confined channel complexes in Pliocene can be characterized by three major categories of erosional confined channel complexes,erosional/external aggradational confined channel complexes and aggradational confined channel complexes according to the difference of sedimentary fill.This study reveals that aggradational channel complexes are richer in reservoir than other two types.They are composite features made up of smaller various sand-rich sub-environments,such as inside channels,frontal splays,crevasse splays and overbanks that can be identified by seismic anomaly process method.It is inferred that some sands with larger thickness and high vertical continuity probably

关 键 词：若开盆地 上新统 斜坡水道复合体 侵蚀 加积 

分 类 号：P512.2[天文地球—地质学]