塔北隆起西部地区白垩系碎屑岩油气成藏规律及成藏模式_徐壮.pdf

第 35 卷 第 2 期2023 年 3 月岩性油气藏LITHOLOGIC RESERVOIRSVol.35 No.2Mar.2023徐壮等：塔北隆起西部地区白垩系碎屑岩油气成藏规律及成藏模式收稿日期：2022-04-19；修回日期：2022-06-25；网络发表日期：2022-09-16基金项目：111 引智项目“沉积盆地动力学与油气富集机理”（编号：B14031）、核资源与环境国家重点实验室自主基金“高放废物地质处置库围岩阻滞机理研究”（编号：2020Z09）联合资助。第一作者：徐壮（1989），男，博士，讲师，主要从事沉积储层评价方面的科研和教学工作。地址：（330013）江西省南昌市经开区广兰大道418 号。Email：。文章编号：1673-8926（2023）02-0031-16DOI：10.12108/yxyqc.20230204引用：徐壮，石万忠，王任，等.塔北隆起西部地区白垩系碎屑岩油气成藏规律及成藏模式 J.岩性油气藏，2023，35（2）：31-46.Cite：XU Zhuang，SHI Wanzhong，WANG Ren，et al.Hydrocarbon accumulation law and model of Cretaceous clastic rocks in westernTabei uplift J.Lithologic Reservoirs，2023，35（2）：31-46.塔北隆起西部地区白垩系碎屑岩油气成藏规律及成藏模式徐壮1，2，石万忠3，王任3，骆福嵩4，夏永涛4，覃硕3，张晓3（1.东华理工大学 核资源与环境国家重点实验室，南昌 330013；2.东华理工大学 地球科学学院，南昌 330013；3.中国地质大学 资源学院，武汉 430074；4.中国石化西北油田分公司 勘探开发研究院，乌鲁木齐 830011）摘要：以岩心观察、物性分析、地球化学分析和三维地震资料为基础，通过单井、连井沉积相分析、地震精细解释及优势砂体识别等方法，从油气来源、油气充注特征、输导体系及储盖组合等4个方面对塔北隆起西部地区白垩系碎屑岩油气成藏规律及模式进行了研究。研究结果表明：研究区白垩系油气具有“陆源”特征，石油主要来自库车坳陷三叠系湖相烃源岩，天然气主要来自库车坳陷侏罗系煤系烃源岩，区内深部三叠系海相烃源岩贡献极小。研究区白垩系油气充注持续时间长，成藏时期晚，早期生油，晚期生气，油成藏于中新世（4.022.0 Ma），气成藏于晚中新世中上新世（3.511.0 Ma），受 2.63.5 Ma 构造隆升影响，气藏成熟度较低。研究区油气输导体系较发育，天山南地区以断裂和不整合面作为主要运移通道；顺北地区以不整合面和巴西改组薄层砂体为运移通道。研究区储层主要发育在舒善河组和巴西改组，含砂率一般高于 60%，与其上部发育的连续泥岩构成良好的储盖组合；优质储层的分布受沉积相控制，天山南地区优质储层主要分布在扇三角洲前缘砂坝及滩坝，顺北地区优质储层主要分布在辫状河三角洲前缘朵体，目前探井未钻遇朵体最高部位，油气显示相对较差；顺北地区储层物性更佳。研究区天山南与顺北地区因断裂活动强度及储盖组合特征存在差异造成了二者的油气藏类型不同，前者以低幅度构造、构造-岩性复合油气藏为主，后者以规模较小的岩性油气藏为主。关键词：成藏模式；陆相烃源岩；辫状河三角洲；构造-岩性复合圈闭；碎屑岩储层；下白垩统；天山南地区；顺北地区；库车坳陷；塔北隆起西部中图分类号：TE122.1；P618.13文献标志码：AHydrocarbon accumulation law and model of Cretaceousclastic rocks in western Tabei upliftXU Zhuang1，2，SHI Wanzhong3，WANG Ren3，LUO Fusong4，XIAYongtao4，QIN Shuo3，ZHANG Xiao3（1.State Key Laboratory of Nuclear Resources and Environment，East China University of Technology，Nanchang 330013，China；2.School of Earth Sciences，East China University of Technology，Nanchang 330013，China；3.Faculty of Earth Resources，China University of Geosciences（Wuhan），Wuhan 430074，China；4.Research Institute of Exploration and Production，Sinopec Northwest Oilfield Company，Urumqi 830011，China）Abstract：Based on core observation and physical property，geochemical analysis and 3D seismic data，through32岩性油气藏第 35 卷第 2 期sedimentary facies analysis of single well and well-tie profile，fine seismic interpretation and identification ofdominant sand bodies，the hydrocarbon accumulation law and model of Cretaceous clastic rocks in western Tabeiuplift were studied from the aspects of oil source，oil and gas charging characteristics，transport system and reservoir-cap assemblage.The results show that：（1）The Cretaceous oil and gas in the study area has the characteristics ofterrigenous origin.The oil mainly comes from Triassic lacustrine source rocks in Kuqa Depression，the gas mainlycomes from Jurassic coal-measure source rocks in Kuqa Sag，while the deep Triassic marine source rocks contributea little to oil and gas.（2）The Cretaceous oil and gas charging in the study area lasted for a long time，and the accu-mulation period was late.The accumulation can be divided into two phases：oil generation in the early period andgas accumulation in the late period.Oil accumulation occurred in the Miocene（4.0-22.0 Ma），and gas accumulation occurred in the early Pleistocene（3.5-11.0 Ma）.Affected by the structural uplift of 2.6-3.5 Ma，the gas reser-voir maturity was low.（3）The oil and gas transport system in the study area is well developed.Faults and unconformities are used as the main migration channels in southern Tianshan Mountains.The unconformity surface andthin sand bodies of Baxigai Formation are the migration channels in Shunbei area.（4）The reservoirs in the studyarea are mainly developed in Shushanhe Formation and Baxigai Formation，with sand content generally higherthan 60%，which constitute a good reservoir-cap assemblage with the continuous mudstone developed in the upperpart.The distribution of high-quality reservoirs is controlled by sedimentary facies.The high-quality reservoirs insouthern Tianshan Mountains are mainly distributed in the front sand bar and beach-bar of fan delta，while thehigh-quality reservoirs in Shunbei area are mainly distributed in front lobe of braided river delta.At present，theexploration wells are not at the highest part of the lobe，and the oil and gas shows are relatively poor.the reservoirproperties in Shunbei area are better.（5）Due to different fault activities and reservoir-cap assemblages，there areobvious differences in the types of oil and gas reservoirs between southern Tianshan Mountains and Shunbei area.Theoil and gas reservoirs in southern Tianshan Mountains are mainly low-amplitude structural and structural-lithologiccomposite reservoirs.The oil and gas reservoirs in Shunbei area are mainly lithologic reservoirs with small scale.Key words：accumulation model；continental source rock；braided river delta；tectonic-lithologic trap；clasticreservoir；Lower Cretaceous；southern Tianshan Mountains；Shunbei area；Kuqa Depression；western Tabei uplift0引言塔北隆起西部地区碎屑岩油气资源丰富，发育中、新生界陆相含油气系统，碎屑岩有利储层沉