川西南地区中二叠统茅口组层序—岩相古地理特征  

SEQUENCE-LITHOFACIES PALEOGEOGRAPHIC CHARACTERISTICS OF MIDDLE PERMIAN MAOKOU FORMATION IN THE SOUTHWESTERN SICHUAN BASIN

作　　者：刘孟琦 徐胜林[1] 胡婧[2] 陈聪 郝毅 李富祥 雍伟 呼唤 王重闲 LIU Mengqi;XU Shenglin;HU Jing;CHEN Cong;HAO Yi;LI Fuxiang;YONG Wei;HU Huan;WANG Chongxian(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Northwest Sichuan Gas Field,Southwest Oil and Gasfield Com pany,PetroChina,Jiangyou,Sichuan 621700,China;Eaploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610041,China;Hangzhou Research Institute of Geology,PetroChina Research Institute of Petroleum Eploration&Development,Hangzhou,Zhejiang 310023,China)

机构地区：[1]成都理工大学沉积地质研究院,四川成都610059 [2]中国石油西南油气田分公司川西北气矿,四川江油621700 [3]中国石油西南油气田公司勘探开发研究院,四川成都610041 [4]中国石油杭州地质研究院,浙江杭州310023

出　　处：《矿物岩石》2023年第4期120-131,共12页Mineralogy and Petrology

基　　金：国家自然科学基金(项目批准号:42172132)。

摘　　要：川西南地区中二叠统茅口组是重要的油气勘探层位,具有较大的油气勘探潜力,但有关该地区茅口组岩相古地理特征及其展布规律缺乏系统深入的研究。本次研究综合2条野外剖面、23口钻井岩芯、录井、测井资料与160件显微薄片,系统开展了川西南地区茅口组层序地层与层序岩相古地理特征研究。结果表明:川西南地区中二叠统茅口组可识别出4个层序界面及3个三级层序(SQ1~SQ3);发育了开阔台地、台地边缘、台地边缘斜坡和陆棚4种沉积相,开阔台地为研究区主要沉积相类型;以三级层序为编图单元编制了3张岩相古地理图:SQ1沉积期研究区台内滩不发育,主体以开阔台地开阔海亚相和台内洼地亚相为主,台缘斜坡相—陆棚相在宝兴以北发育;SQ2沉积期台内滩发育,形成大型台内滩组合体,台缘斜坡相—陆棚相向内部延伸至大邑—邛崃地区,开阔台地台内洼地亚相主要发育龙泉—眉山地区,北东南西相展布;SQ3沉积期开阔台地台内洼地亚相仅在研究区零星发育,台缘斜坡相—陆棚相沉积环境向西北部退缩,台内滩相对不发育,零星分布;结合研究区沉积演化模式图,揭示了川西南地区茅口组滩体的发育主要位于SQ2期,茅口组顶部地层厚度的减薄受后期峨眉山玄武岩喷发而非同期岩溶作用。The Middle Permian Maokou Formation in southwest Sichuan is an important oil and gas reservoir,thus embracing great potential of oil and gas exploration.However,there is a lack of systematic and in-depth study on the lithofacies paleogeographic characteristics and distribution rules of the Maokou Formation in this area.In this paper,comprehensive data such as 2 field profiles,23 drilling cores,well logs and well logging data,and 160 thin sections are used to study the sequence stratigraphy and sequence lithofacies paleogeographic characteristics of Maokou Formation in southwest Sichuan.The results show that four sequence interfaces and three tertiary sequences(SQ1-SQ3)can be identified in the study area.Four sedimentary facies,including open platform,platform margin,platform margin slope and shelf,are developed with the open platform as the main sedimentary facies here.Accordingly,three lithofacies paleogeographic maps are compiled with the three-level sequence which is considered as the mapping unit.In the sedimentary stage of SQ1,the platform beach is poorly developed in the study area,and the main facies are open sea subfacies of open platform and depression subfacies in platform.While the platform margin slope facies and shelf facies are developed in the north of Baoxing area.In the sedimentary period of SQ2,the inner platform beach has developed and formed a large inner platform beach assembly.The slope facies and shelf at the edge of the platform are extended internally to Dayi-Qionglai area,and the depression subfacies in the open platform are mainly developed in the Longquan-Meishan area,with a northeast-southwest direction distribution.During the deposition period of SQ3,the depression subfacies in the open platform have only developed sporadically in the study area.The platform margin slop-shelf sedimentary environment is shrunk to the northwest,and the inner beach is relatively undeveloped and sporadically distributed.Comprehensive analysis of the sedimentary evolution model map reveals that the develo

关 键 词：茅口组 层序地层 岩相古地理 沉积模式 川西南地区 

分 类 号：P531[天文地球—古生物学与地层学] P534.46[天文地球—地质学]