柯坪地区中下寒武统走滑断裂带方解石脉期次、古流体演化与油气充注历史  

Division of Calcite Veins Stage,Paleo-Fluid Evolution and Hydrocarbon Charging History in the Middle and Lower Cambrin Strike-Slip Fault Zone in Keping Area,Northwest of Tarim Basin

作　　者：刘建章[1,2] 陈诚 蔡忠贤[1,2] 李杰 吴正洲[1,3] Liu Jianzhang;Chen Cheng;Cai Zhongxian;Li Jie;Wu Zhengzhou(Key Laboratory of Tectonics and Petroleum Resources,Ministry of Education,China University of Geosciences,Wuhan 430074,China;School of Earth Resources,China University of Geosciences,Wuhan 430074,China;The No.1 Gas Production Plant,Jianghan Oilfield Branch Company,SINOPEC,Chongqing 404120,China)

机构地区：[1]中国地质大学构造与油气资源教育部重点实验室,湖北武汉430074 [2]中国地质大学资源学院,湖北武汉430074 [3]中国石油化工股份有限公司江汉油田分公司采气一厂,重庆404120

出　　处：《地球科学》2023年第6期2189-2203,共15页Earth Science

基　　金：国家重点研发计划课题(No.2019YFC0605502);国家自然科学基金(No.42072179).

摘　　要：新疆柯坪地区野外露头中下寒武统走滑断裂带充填多期方解石脉和固体沥青,是揭示流体活动和油气成藏过程的重要媒介.在野外露头断裂带中方解石脉、沥青充填特征观察的基础上,利用岩石薄片、阴极发光、微区原位稀土元素、碳氧同位素及流体包裹体等测试技术,厘定方解石脉形成期次、成脉流体性质及来源,揭示成脉古流体演化及其与油气充注的耦合关系.结果表明,柯坪地区中下寒武统走滑断裂中发育4~5期方解石脉(C1、C2、C3、C4、C5);C1成脉流体为地层水,部分混合了上覆阿瓦塔格组地层卤水;C2、C3成脉流体主要为地层水与含烃热液流体的混合,但C3成脉温度稍低;C4成脉流体也主要为地层水,存在大气淡水的混合;C5成脉流体为地层水、含烃流体和大气淡水的混合.5期方解石脉分别形成于加里东中晚期、海西中晚期、印支-燕山中期、燕山晚期和喜马拉雅期,3期油气充注于海西中晚期、印支-燕山中期和喜马拉雅期.海西中晚期、印支-燕山中期可能是柯坪地区中下寒武统原生油气藏的主要形成时期,喜马拉雅期是原生油气藏破坏、调整和再聚集期.喜马拉雅期定型、与走滑断裂相关圈闭也具有优越成藏条件.Multi-stage calcite veins and solid bitumen filled in the Middle and Lower Cambrian strike-slip fault zone of the field outcrops for Keping Area,northwest of Tarim basin,are important medium to reveal the fluid activity history and hydrocarbon accumulation process.Based on the observation of the filling and distribution characteristics of calcite veins and bitumen in outcrop of strike-slip fault zones,the paragenetic sequence of calcite veins and bitumen and the origin fluid properties were determined using the thin section observation,cathodoluminescence,in-situ trace and rare earth element testing,carbon and oxygen isotopes measurement,system analysis of fluid inclusion,and the evolution of paleo-fluid in the strike-slip fault zones of the Middle and Lower Cambrian and its coupling relationship with hydrocarbon charging process were investigated.The results show that there are at least five phases of calcite veins in the strike-slip fault zones of the Middle and Lower Cambrian for Keping area of Xinjiang,C1,C2,C3,C4 and C5 respectively.The C1 calcite vein-forming fluid was mainly derived from formation water of the local layer and partly mixed with the brine of the Awatage Formation that infiltrated along the strike-slip fault.The C2 and C3 calcite veinforming fluids were mainly the mixture of formation water and hydrocarbon-bearing hydrothermal fluids,but the formation temperature of C3 was slightly lower.The C4 calcite vein-forming fluid was mainly formation water,and there was mixing of atmospheric fresh water.The C5 calcite vein-forming fluid was mainly the mixture of formation water,hydrocarbon-bearing hydrothermal fluid and atmospheric fresh water.The formation stages of C1,C2,C3,C4 and C5 calcite veins were associated with tectonic activities of Keping area and generated in the Middle and Late Caledonian periods,Middle and Late Hercynian periods,Indosinian to Middle Yanshanian periods,Late Yanshanian and Himalayan periods,respectively.Three hydrocarbon charging phases were recognized,the Middle and Late

关 键 词：油气充注 古流体演化 方解石脉 走滑断裂带 柯坪地区 石油地质. 

分 类 号：P618.1[天文地球—矿床学]