库车坳陷克拉苏构造带巴什基奇克组储层中石英胶结物成因机制  

Genetic mechanism of quartz cements in Bashijiqike Formation reservoirs of Kelasu Structural Belt,Kuqa Depression

作　　者：王健[1,2,3] 李振坤[1] 操应长 杨海军 莫涛[4] 汪顺宇 WANG Jian;LI Zhenkun;CAO Yingchang;YANG Haijun;MO Tao;WANG Shunyu(State Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao 266580,China;School of Geosciences in China University of Petroleum(East China),Qingdao 266580,China;Laboratory for Marine Mineral Resources,Qingdao Marine Science and Technology Center,Qingdao 266071,China;PetroChina Tarim Oilfield Company,Korla 841000,China)

机构地区：[1]深层油气全国重点实验室(中国石油大学(华东)),山东青岛266580 [2]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [3]青岛海洋科技中心海洋矿产资源评价与探测技术国家功能实验室,山东青岛266071 [4]中国石油塔里木油田分公司,新疆库尔勒841000

出　　处：《中国石油大学学报(自然科学版)》2025年第1期14-21,共8页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家自然科学基金项目(42172146);山东省泰山学者青年专家项目(tsqn202312111);国家重点研发计划(2022YFE0203400);深层油气全国重点实验室基金项目(SKLDOG2024-ZYRC-05)。

摘　　要：克拉苏构造带巴什基奇克组储层中常见石英胶结物,通过偏光显微镜、阴极发光、扫描电镜、薄片鉴定资料分析、激光微区分析等多种手段,对石英胶结物的微观特征、分布特征以及成因机制进行系统研究。结果表明,偏光显微镜下石英胶结物干净无杂质,通常以加大边或充填孔隙的形式存在,还常见其在裂缝中形成自形—半自形石英。按照阴极发光特征可将石英胶结物分为两期,第一期在阴极射线下几乎不发光,呈蓝黑色,第二期发光略亮于第一期,呈紫黑色。横向上,石英胶结物主要分布在克深和克拉3段,在大北段东部其含量也较高;纵向上,石英胶结物主要分布在靠近不整合处。第一期石英胶结物Li、Al含量普遍高于石英颗粒,Ti含量低于石英颗粒。第一期石英胶结物的物质来源主要为溶解的长石,成岩流体为大气水。白垩纪末研究区发生构造抬升时,大气水淋滤溶解了大量长石而富含H_(4)SiO_(4)、Na^(+)、Ca^(2+)等物质,当H_(4)SiO_(4)达到一定活度时,石英即发生沉淀。第二期石英胶结物成因可能和有机酸充注有关,也可能和黏土矿物转化有关,有机酸沿构造裂缝充注到储层中,溶解了附近的长石并发生石英沉淀,黏土矿物转化释放的SiO_(2)被泥岩排出的地层水带到附近裂缝中产生石英胶结物。Quartz cements are prevalent in Bashijiqike Formation reservoirs of Kelasu Structural Belt.This study systematically examines the microscopic characteristics,distribution patterns,and genetic mechanisms of quartz cements using optical microscopy,cathodoluminescence,electron microscope,thin section analysis,and laser ablation-inductively coupled plasma-mass spectrometry microanalysis.Under optical microscopy,quartz cements appear clean and typically manifest as overgrowths or pore-filling materials,often forming euhedral to sub-euhedral quartz crystals within fractures.Cathodoluminescence analysis identifies two distinct phases of quartz cements:the first phase exhibits nearly non-luminous bluish-black characteristics,while the second phase is slightly brighter,appearing purple-black.Horizontally,quartz cements are primarily distributed in the Keshen and Kela 3 sections,with elevated content also observed in the eastern part of the Dabei section.Vertically,they are concentrated near unconformities.First-phase quartz cements contain higher concentrations of Li and AI compared to quartz particles,lower concentrations of Ti.The first-phase quartz cements originate from feldspar dissolution driven by diagenetic fluids derived from atmospheric water.During the late Cretaceous structural uplift,atmospheric water dissolved feldspar,enriching the fluid with H_(4)SiO_(4),Na^(+),Ca^(2+),and other ions.Quartz precipitated as H_(4)SiO_(4) reached a critical activity threshold.The second-phase quartz cements likely formed due to organic acid injection and clay mineral transformation.Organic acids migrating along structural fractures dissolved feldspar,facilitating quartz precipitation.Additionally,SiO_(2) released from the transformation of clay minerals was transported to nearby fractures by formation water expelled from mudstone,leading to quartz cementation.

关 键 词：石英胶结物 成因机制 巴什基奇克组 克拉苏构造带 

分 类 号：TE122.1[石油与天然气工程—油气勘探]