库车坳陷下侏罗统沉积特征及砂体展布  

SEDIMENTARY CHARACTERISTICS AND SANDSTONE BODY DISTRIBUTION OF THE LOWER JURASSIC IN KUQA DEPRESSION

作　　者：张惠良[1] 寿建峰[1] 陈子料[1] 王少依[1] 杨晓宁[2] 皮学军[3] 蔡振忠[3] 

机构地区：[1]中国石油勘探开发研究院杭州石油地质研究所,浙江杭州310023 [2]成都理工学院沉积地质研究所,四川成都610059 [3]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》2002年第3期47-58,共12页Journal of Palaeogeography：Chinese Edition

基　　金：中国石油集团公司石油天然气储层重点实验室基金资助

摘　　要：库车坳陷位于塔里木盆地北部 ,北缘是南天山山前断裂带 ,南缘是塔北隆起 ,呈NEE向展布 ,东西长 2 5 0km ,南北宽 2 0— 6 0km ,面积约 2 1170km2 。下侏罗统自下而上发育阿合组、阳霞组。对吐格尔明、克孜勒努尔、库车河剖面及依南 2井岩芯观察发现 ,阿合组和阳霞组按其岩性特征均可以划分出 5个岩性段 ,各个岩性段在全区具有对比性。还可分出 4类和 17个亚类岩相。阿合组细砂岩以上的粗碎屑岩含量为 80 %以上 ;阳霞组细砂岩以上的碎屑岩含量为 5 0 %— 6 0 %。砂岩厚度占总地层厚度的 5 0 %— 6 0 %以上 ,是油气勘探的重要目的层系。以吐格尔明剖面为代表的依南 2井以东地区的阿合组和阳霞组岩矿特征基本相似 ,以克孜勒努尔地区为代表的依南 2井以西地区有较大差异 ,即阳霞组长石含量几乎为零。两区共同点是以岩屑砂岩为主 ,成分成熟度低 ,结构成熟度中等 ,岩屑含量较高。从岩性组合、沉积构造、微观岩石成分、结构和砂体形态等方面的综合分析认为 ,辫状三角洲沉积体系是该区阿合组和阳霞组的主要沉积体系。阿合组砂体纵向上以多个辫状三角洲平原上的辫状分流河道砂岩加积复合为主 ,横向上指状镶嵌叠置呈东西向展布。阳霞组第 3岩性段砂体纵向上以多个辫状三角洲前缘上的水下辫状分流河道砂岩加积复合?Kuqa Depression which the northern border was faults before the southern margin of Tianshan mountain and the southern border was the northern uplift in Tarim basin was located in the north of Tarim basin and extended in direction of NEE. The length in direction of EN was 250 km and the width in the dirction of NS was 20-60 km, the area was 21 170km 2. Lower Jurassic was divided into the Ahe Formation and Yangxia Formation from lower to upper,the Ahe Formation and Yangxia Formation were divdided into five lithologic Members respectively from lithologic character of sections of Tugeerming, Kezilenuer, Kuqahe and Well Yinan 2. These lithologic Members can be correlated in the Depression. Four types and seventeen subtypes of lithofacies were classified. The content of coarse clastic rocks over fine sandstone was over 80% in the Ahe Formation, and that in the Yangxia Formation was 50%-60%.They are important target stratum of exploration of oil and gas. The mineral character of sandstones of the Ahe Formation in the area on the east of well Yinan 2 was similar to that of the Yangxia Formation, and that on the west of well Yinan 2 was different between the Ahe Formation and Yangxia Formation that the content of feldspar is near to naught. The similar character between the west and east area was that the composition of sandstone was lithic sandstone, and had high content of debris,low compositional and textural maturrity. Braided delta depositional system was main depositional system of the Ahe Formation and Yangxia Formation. The sandstone architecture of the Ahe Formation was vertical accretion of various distributional channels sandstone of braid deltaic plain and stacked interfingerly in WE.The architecture of the sandstone of the Member 3 of the Yangxia Formation was similar to that of the Ahe Formation ,but the sandstone was underwater distributional channel sandstone.That of the Member 2,3,5 of Yangxia Formation were lateral accretion of river channels sandstone and stacked imbrecately in WE.

关 键 词：库车坳陷 下侏罗统 辫状三角洲 砂体 储层 塔里木盆地 

分 类 号：P618.130.2[天文地球—矿床学] P534.52[天文地球—地质学]