塔里木盆地顺托果勒低隆起走滑断裂带流体时空分布及油气成藏意义  

Spatial-temporal distribution of fluid activities and its significance for hydrocarbon accumulation in the strike-slip fault zones,Shuntuoguole low-uplift,Tarim Basin

作　　者：李慧莉[1,2] 高键[1,2] 曹自成 朱秀香[1,3] 郭小文[4] 曾帅[5] LI Huili;GAO Jian;CAO Zicheng;ZHU Xiuxiang;GUO Xiaowen;ZENG Shuai(Key Laboratory of Geology and Resources in Deep Stratum,SINOPEC,Beijing 102206,China;Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 102206,China;Exploration and Development Research Institute,Northwest Oilfield Branch,SINOPEC,Urmqi 830011,China;School of Earth Resources,China University of Geosciences(Wuhan),Wuhan 430074,China;College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石化深部地质与资源重点实验室,北京102206 [2]中国石化石油勘探开发研究院,北京102206 [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 [4]中国地质大学(武汉)资源学院,湖北武汉430074 [5]中国石油大学(北京)地球科学学院,北京102249

出　　处：《地学前缘》2023年第6期316-328,共13页Earth Science Frontiers

基　　金：国家自然科学基金企业联合创新发展联合基金项目(U19B6003)。

摘　　要：塔里木盆地顺北油气田走滑断裂对成储和成藏具有重要的控制作用。本文采集研究区8条主要走滑断裂上23口钻井岩心中的构造成因裂缝充填方解石脉,开展断裂流体耦合活动研究。根据方解石脉微观岩相(成岩矿物类型和阴极发光特征)、岩石化学(稀土元素、碳氧锶同位素)和方解石原位U-Pb定年结果,将方解石脉分为3期。第一期方解石脉在东西部数条断裂带内普遍发育,方解石岩石化学特征指示流体来源于中下奥陶统地层水;方解石原位U-Pb年龄为474~444 Ma,时代为加里东中期。第二期方解石脉主要在顺北5号带以东断裂带内发育普遍,方解石岩石化学特征指示来源于下部寒武系地层水和埋藏期深部热流体;方解石原位U-Pb年龄为441~403和374~326 Ma,时代集中分布在加里东晚期—海西早期。第三期方解石脉在5号带、4号带和顺南地区少数样品较为发育,方解石岩石化学特征指示埋藏期深部热流体特征,方解石原位U-Pb年龄为295.9~232 Ma,时代主要为海西晚期。三期方解石脉形成时期与断裂活动期次相吻合。方解石脉含烃包裹体产状和特征指示加里东晚期—海西早期和海西晚期液态烃充注和液态烃热裂解演化过程。本文利用构造成因裂缝充填方解石微区原位U-Pb定年,确定走滑断裂形成时间的方法,以及结合烃类包裹体分析直接确定油气成藏时限的方法,对于研究多旋回盆地多源多期油气成藏过程有推广应用价值。The strike-slip faults in the Shunbei oil and gas field,Tarim Basin are essential for the reservoir formation and hydrocarbon accumulation.This research selects carbonate core samples containing fractured calcite veins from 23 drilling wells in eight major strike-slip faults in Shuntuoguole area to investigate fault-fluid interaction in the oil and gas field.Based on the petrography(diagenetic mineral types and cathodoluminescence characteristics)and lithogeochemistry(rare earth elements,strontium isotopes,carbon and oxygen isotopes)of calcite veins and laser ablation in situ U-Pb dating of calcite,the fractured calcite veins are divided into three types based on their formation environment and stage.Calcite veins formed in the first stage(474-444 Ma)are widely distributed in many faults,and their lithogeochemical characteristics indicate the diagenetic fluids are derived from formation water of the Middle-Lower Ordovician.Calcite veins formed in the second stage(441-403 Ma)are mostly distributed in fault zones east of Shunbei No.5 fault,and Cambrian formation water and deep thermal fluids of the burial period are the sources of the diagenetic fluids.Calcite veins formed in the third stage(374-326 Ma)-with diagenetic fluids likely originated from deep thermal fluids-are only observed in a few samples from Shunbei Nos.4 and 5 strike-slip faults and Shunnan area.In situ U-Pb dating results suggest the three calcite phases coincide with faulting events in the Middle Caledonian,Late Caledonian-Early Hercynian,and Late Hercynian,respectively.Moreover,the occurrence and characteristics of hydrocarbon-bearing inclusions in calcite veins imply liquid hydrocarbon charging during the Late Caledonian-Early Hercynian and Late Hercynian and crude oil cracking in the study area.The method of direct dating of strike-slip faults by in-situ U-Pb dating of carbonate minerals has broad applications,and the combination of in situ calcite U-Pb dating and hydrocarbon inclusion analysis can directly establish the time of hydrocarbon ch

关 键 词：方解石脉 断裂流体耦合活动 油气成藏 顺北油气田 塔里木盆地 

分 类 号：TE121.1[石油与天然气工程—油气勘探] TE122.1