川西南部地区下二叠统栖霞阶层序地层特征及岩相古地理  

Sequence Stratigraphy and Lithofacies Paleogeography of the Lower Permian Qixia Stage in Southwestern Sichuan Basin

作　　者：汤艳玲 李凌[1,2,3] 谭秀成 李明隆[1,2,3] 芦飞凡 张本健 TANG YanLing;LI Ling;TAN XiuCheng;LI MingLong;LU FeiFan;ZHANG BenJian(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China;Research Branch of Southwest Petroleum University,Key Laboratory of Carbonate Reservoirs,CNPC,Chengdu 610500,China;Natural Gas Geology Key Laboratory of Sichuan Province,Southwest Petroleum University,Chengdu 610500,China;School of Earth and Space Sciences,Peking University,Beijing 100871,China;Exploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu 610095,China)

机构地区：[1]油气藏地质及开发工程全国重点实验室(西南石油大学),成都610500 [2]中国石油天然气集团有限公司碳酸盐岩储层重点实验室西南石油大学研究分室,成都610500 [3]西南石油大学天然气地质四川省重点实验室,成都610500 [4]北京大学地球与空间科学学院,北京100871 [5]中国石油西南油气田勘探开发研究院,成都610095

出　　处：《沉积学报》2024年第2期575-592,共18页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(42172166)。

摘　　要：【目的】西接康滇古陆的四川盆地西南部下二叠统栖霞阶近年来展示出良好的勘探潜力,然而针对该地区地层充填规律及古地理格局的观点还并不统一,严重制约了下一步盆内精细的油气勘探和井位部署。【方法】以四川盆地西南部下二叠统栖霞阶梁山组和栖霞组为研究对象,综合利用野外剖面、钻井岩心和测录井等资料,在岩石类型与沉积相分析的基础上,运用海相碳酸盐岩层序地层学原理与方法,对栖霞阶层序界面进行识别。并采用单因素分析多因素综合作图法,以三级层序为编图单位,结合优势相原则,分别绘制研究区栖霞阶SQ0+SQ1和SQ2层序岩相古地理图。【结果】在栖霞阶中识别出4个三级层序界面,从下到上分别为梁山组底界面(I型)、栖一段内部界面(II型)、栖一段\栖二段界面(II型)和栖霞组\茅口组界面(I型),并将其划分为3个三级层序,每个层序均由海侵域和高位域组成。通过层序地层格架的对比分析,认为栖霞阶下部的SQ0层序大致对应于传统划分的梁山组+栖一段下部地层,仅发育于研究区内的栖霞阶地层沉积前古地貌低地,并且具有向古地貌高地超覆的层序充填特征,中部的SQ1层序和上部的SQ2层序则遍布全区。川西南栖霞阶层序岩相古地理格局总体上表现为西接康滇古陆的海相碳酸盐岩台地,古地貌和沉积相带分异比较明显,自西向东依次为:康滇古陆及其东缘的潮坪、台内洼地、台内丘滩体,以及开阔—半局限海台地,而且沿台内坡折带发育的台内丘滩体往往具有环洼规模分布的趋势。【结论】通过剖析台内坡折带对碳酸盐岩成储的影响,指出SQ2层序(栖二段)是研究区栖霞阶最有利于台内丘滩体这一潜力储集相带发育的层位,环台洼坡折带发育的丘滩体相带附近是有利的勘探区。从层序地层学角度重新认识栖霞阶充填模式及岩相古地理特征,为川�[Objective]The Lower Permian Qixia Stage in southwest Sichuan Basin has shown significant exploration potential in recent years,but the views on the sedimentary filling pattern and paleogeographic framework in this area are not unified,which seriously restricts the further oil and gas exploration and well location deployment in the basin.[Methods]This study of the Lower Permian Liangshan Formation and Qixia Formation in southwestern Sichuan Basin was based on the comprehensive use of field profiles,drilling cores and logging data,and analysis of rock types and sedimentary facies.The application of the principles and methods of marine carbonate stratigraphical sequencing led to the identification of third-order sequence interfaces in the Qixia Stage.Single-factor analysis and multi-factor comprehensive mapping were adopted,taking the three-level sequence as the mapping unit.Combining these with the dominant phase,maps of the SQ0+SQ1 and SQ2 sequence paleogeographic lithofacies were drawn for the Qixia Stage in the study area.[Results]Four third-order sequence interfaces were identified in the Qixia Stage,from bottom to top:lower interface of Liangshan Formation(SB I),inner interface of Qixia Formation Group 1 section(SB II),interface of Qixia Formation Groups 1 and 2(SB II)and interface of the Qixia Formation and Maokou Formation(SB I).These occurred in three tertiary sequences,each consisting of a transgressive domain and a high-order domain.Comparative analysis of the sequential stratigraphic framework suggested that the SQ0 sequence of the lower Qixia Stage corresponds roughly to the Liangshan Formation.In the lower Qixia Formation Group 1 section,SQ0 is evident only in the paleogeomorphic lowland before the deposition of Qixia Stage in the study area,with a filling sequence overlapping a paleogeomorphic highland.Sequence SQ1 in the middle region and SQ2 sequence in the upper region are found throughout the area.The sequence in the southwestern Sichuan Basin consists of a marine carbonate platform bordering the

关 键 词：层序地层 地层充填模式 古地理格局 地质意义 栖霞阶 四川盆地西南部 

分 类 号：P618.13[天文地球—矿床学]