塔里木盆地库车坳陷白垩系巴什基奇克组岩相古地理

Lithofacies Paleogeography of Cretaceous Bashijiqike Formation in Kuqa Depression,Tarim Basin

为明确塔里木盆地库车坳陷沉积岩相、微相特征及其与古地理背景关系,依据露头微相观测、岩心微相描述、成像测井岩相刻画、构造演化恢复、沉积因素综合分析研究认为,白垩系巴什基奇克组岩相古地理总体受南天山、温宿凸起、库鲁克塔格山物源三重控制,其中克拉苏—依奇克里克冲断带西段的巴什基奇克组主要源于南天山物源,塔北隆起西部的巴什基奇克组主要源于温宿凸起物源,塔北隆起中东部的巴什基奇克组主要源于库鲁克塔格山物源,秋里塔格冲断带为3物源交汇区,乌什凹陷受南天山物源和温宿凸起物源双重控制;克拉苏—依奇克里克冲断带西段主要发育辫状河三角洲前缘中—细砂岩和扇三角洲前缘水下分流河道粉—细砂岩2类典型微相砂岩,砂体总体叠置连片展布,残余厚度150～260 m;塔北隆起以扇三角洲前缘水下分流河道中—细砂岩和辫状河三角洲前缘水下分流河道细—粉砂岩沉积为主,夹河口坝粉—细砂岩,砂体总体呈厚层连片展布,残余厚度100～300 m.白垩系巴什基奇克组＂满坳富砂＂为库车坳陷油气战略突破提供重要理论依据。

To identify the characteristics of sedimentary facies and microfacies and their relationships with the paleogeographic setting,based on microfacies observation of outcrops,microfacies description of cores,characterization of imaging-logging facies,restoration ofstructural evolution and superimposed analysis of sedimentary elements,it is considered that Cretaceous Bashijiqike formation is generallycontrolled by 3 factors such as southern Tianshan mountain,Wensu swell and Kuruktag mountain in provenance.Bashijiqike formationprovenance in the Kelasu thrust belt is mainly originated from southern Tianshan mountain,and that in the western part of Tabei uplift isfrom Wensu swell,and that in the mid-eastern part of Tabei uplift from Kuruktag mountain.Qiulitag structural belt is the intersection areaof these 3 provenances and Wushi sag is controlled by both southern Taishan mountain and Wensu uplift; 2 typical sandstones such asbraided delta-front mid-fine sandstone and fan-delta front underwater distributary-channel silt-fine sandstone are mainly developed in theKelasu thrust belt.Sandbodies are superimposed and distributed continuously with the residual thickness of 150～260 m; Tabei uplift isdominated by mid-fine sandstones of fan-delta front underwater distributary-channel facies and fine-silt sandstones of braided delta-frontunderwater distributary-channel facies mixed with some silt-fine sanstones of river mouth bar facies.The thick sandbodies are generally dis-tributed continuously in Tabei uplift with the residual thickness of 100～300 m.The understanding as＂the sandstones are distributed in thewhole depression＂in Cretaceous Bashijiqike formation provides a significant theoretical basis for the breakthrough of the oil and gas strate-gy in Kuqa foreland area.