古陆架砂脊沉积特征及其石油地质意义:以塔里木盆地志留系柯坪塔格组下段为例  

Sedimentary Characteristics and Petroleum Geological Significance of Ancient Shelf Sand Ridges:A Case Study of Lower Member of Silurian Kepingtage Formation in Tarim Basin

作　　者：杨帅[1,2] 刘晓峰[1,2] 陆永潮[1,2] 杨素举[3] 

机构地区：[1]中国地质大学构造与油气资源教育部重点实验室,湖北武汉430074 [2]中国地质大学资源学院,湖北武汉430074 [3]中国石化西北油田分公司勘探开发研究院,新疆乌鲁木齐830011

出　　处：《地球科学（中国地质大学学报）》2014年第7期858-870,共13页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金(No.41202086)

摘　　要：塔里木盆地顺托果勒低隆起志留系柯坪塔格组下段发育的陆架砂脊为了解古陆架砂脊沉积建造提供了一个理想实例.利用测井和岩心资料,根据沉积物的岩性和沉积构造特征,将陆架砂脊划分为6个岩性相:块状层理中-细砂岩性相(FA1)、丘状交错层理中-细砂岩性相(FA2)、含撕裂状泥砾的中-细砂岩性相(FA3)、双向交错层理含粘土层的细砂岩性相(FA4)、潮汐层理的细砂岩与泥岩互层岩性相(FA5)和水平层理陆架泥岩性相(FA6);依据岩性相的组合特征,将陆架砂脊划分为4个沉积微相:砂脊核微相(FA1-FA2-FA3)、砂脊内缘微相(FA4)、砂脊外缘微相(FA5)和陆架泥微相(FA6);陆架砂脊沉积受陆架潮汐、风暴浪的共同影响.利用钻井约束的三维地震切片属性分析,确定了NE-SW向和NW-SE向两组古陆架砂脊的平面展布特征.古陆架砂脊储层为特低孔、特低渗,其中砂脊核微相储层物性相对较好,平均孔隙度6.96%、平均渗透率0.34×10-3μm2;工业油流主要集中在砂脊核微相储层.古陆架砂脊的砂体多呈脊状或丘状并被厚层的陆架泥披覆,常形成同沉积的微幅背斜-岩性圈闭.Ancient shelf sand ridge deposited in Lower member of Silurian Kepingtage Formation of Shuntuoguole uplift,Tarim basin,provides an ideal example to understand its sedimentary formation characteristics.By using well-logging and core data, shelf sand ridge is divided into 6 lithofacies：massive bedding medium-fine sandstone （FA1）,hummocky cross bedding medi-um-fine sandstone （FA2）,muddy conglomerate-bearing medium-fine sandstone （FA3）,clay layer-bearing bimodal cross bed-ding fine sandstone （FA4）,tidal bedding fine sandstone interbedded with mudstone （FA5）,horizontal bedding shelf mudstone （FA6）according to the lithology and sedimentary structure of sediments.In terms of lithofacies association characteristics, shelf sand ridge whose deposits are affected by shelf tide and storm wave is classified into 4 sedimentary microfacies：sand ridge core microfacies （FA1-FA2-FA3）,sand ridge inner margin microfacies （FA4）,sand ridge external margin （FA5）and shelf mud microfacies （FA6）.The plane distribution characteristics of shelf sand ridge along NE-SW and NW-SE are determined through detailed analysis of three-dimensional seismic slice attributes calibrated with well data.Ancient shelf sand ridge reser-voir has characteristics of extra low porosity and permeability,in which sand ridge core microfacies is better reservoir with av-erage porosity 6.96%,average permeability 0.34×10^-3μm^2 ,and is mainly industrial oil flow concentrated area.Syndeposition-al slightly anticline-lithologic traps are often formed since sandstones of shelf sand ridge present ridge or mound shape and draped by thick-layer shelf mudstone.

关 键 词：古陆架砂脊 岩性相 微相 柯坪塔格组 石油地质 塔里木盆地 

分 类 号：P618.13[天文地球—矿床学]