塔里木盆地西南部昆仑山前下白垩统沉积相特征及石油地质意义  

Characteristics of sedimentary facies and petroleum geological significance of the Lower Cretaceous in front of Kunlun Mountains in southwestern Tarim Basin

作　　者：张惠良[1] 沈扬[1] 张荣虎[1] 李玉文[1] 杨晓宁[1] 刘胜[2] 邱斌[2] 杨芝林[2] 

机构地区：[1]中国石油勘探开发研究院杭州地质研究所,浙江杭州310023 [2]中国石油塔里木油田分公司,新疆库尔勒841000

出　　处：《古地理学报》2005年第2期157-168,共12页Journal of Palaeogeography：Chinese Edition

摘　　要：塔里木盆地西南部沿昆仑山前分布一套逾千米厚的下白垩统碎屑岩,岩性以浅红色中、细砂岩,褐红色砂砾岩、砾岩为主,夹浅红色泥岩和薄层浅灰色细砂岩。按生物组合及岩性特征,自下而上可划分5个岩性段。第1段为灰绿色泥岩段,沉积环境以湖相和前扇三角洲沉积为主;第2段为砂砾岩段,沉积环境以扇三角洲前缘和扇三角洲平原沉积为主;第3段为含砾粗砂岩段,沉积环境以辫状河—辫状河三角洲平原沉积为主;第4段为细砂岩夹泥岩段,沉积环境以辫状河三角洲前缘水下分流河道沉积为主;第5段为泥岩夹砂岩段,沉积环境为辫状河三角洲前缘、前辫状河三角洲和滨浅湖相沉积。沉积环境由快速堆积的扇三角洲—冲积扇向辫状河—辫状河三角洲演化,沉积厚度达10 0 0余米。构造背景为强烈拉张的构造环境,是断陷盆地发育的重要时期。中、细砂岩达70 %以上,砂岩孔隙类型为原生粒间孔,孔隙度10 %～2 0 % ,渗透率(1～10 0 0 )×10 -3 μm2 。A set of clastic rocks with thicknes s of more than one thousand meters was deposited in the Lower Cretaceous in front of the Kunlun Mountains in sou thwestern Tarim Basin.They are mainly red fine-medium grained sandstone,maro o n sandy conglomerate,conglomerate,interbedded with mudstone and thin grey fine sandstone.Based on the group of fossils and lithologic characteristics,the Kez ilesu Group is divided into 5 lithologic members: the first one is the greyish g reen mudstone member whose sedimentary environment is mostly lake and fan delta.The second one is sandy conglomerate whose sedimentary environment is ma inly the front and plain of fan-delta.The third one is thick gravel-be aring sandstone whose sedimentary environment is mainly braided river and braid ed ri ver delta plain.The fourth is mostly fine-grained sandstone interbedded with m u dstone,whose sedimentary environment is subaqueous distributary channel on braided river delta front.The last one is mudstone interbedded with sandston e whose sedimentary environment is braided river delta front,probraided r iver delta and shore-shallow lake.The evolution of se dimentary environments from quickly deposited fan-delta to alluvial fa n -braided river to braided river delta shows the significant developing period of the fault basin.Over 70 percent of the clastic rocks is medium-fine-graine d sandstone,whose pore types are primary intergranular pores with porosity of 10%～20% and permeability of(1～1 000)× 10 -3 μm 2. The Keziles u Grou p is the important strata for oil and gas exploration in the Mesozoic in the Tar im Basin.

关 键 词：塔里木盆地 下白垩统 石油地质意义 昆仑山 西南部 沉积相特征 辫状河三角洲 三角洲前缘 沉积环境 三角洲平原 扇三角洲沉积 红色泥岩 岩性特征 生物组合 河道沉积 湖相沉积 沉积厚度 构造环境 构造背景 盆地发育 孔隙类型 

分 类 号：P534.53[天文地球—古生物学与地层学] P618.130.2[天文地球—地质学]