沉积学报2024，Vol.42Issue(2)：575-592,18.DOI:10.14027/j.issn.1000-0550.2022.043
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
摘要
Abstract
[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 Ba-sin 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 bot-tom 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 do-main.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 ev-ident only in the paleogeomorphic lowland before the deposition of Qixia Stage in the study area,with a filling se-quence 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 Kang-Dian ancient land in the west,with obvious differentiation of paleogeomorphology and sedimentary facies.From west to east,the Kang-Dian land and its eastern margin consisted of a tidal flat,intraplat-form depression,intraplatform mound-shoal,and an open semi-confined platform.In addition,an intraplatform mound-shoal beach developed along the intraplatform slope break zone,tending to surround the intraplatform depres-sion.[Conclusions]Analysis of the influence of the slope break zone on carbonate reservoir formation highlighted that the SQ2 sequence is the most favorable reservoir facies belt in the study area,with favorable exploration areas around the intraplatform mound-shoal facies belt.A new understanding of the filling pattern and paleogeographic litho-facies characteristics of the Qixia Stage,as determined from the sequence stratigraphy,provides a new framework for future reservoir studies and the prediction of favorable exploration areas in the Qixia Formation.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Key words
sequence stratigraphy/sedimentary filling pattern/paleogeographic framework/geological significance/Qixia Stage/southwestern Sichuan Basin分类
天文与地球科学引用本文复制引用
汤艳玲,李凌,谭秀成,李明隆,芦飞凡,张本健..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[J].沉积学报,2024,42(2):575-592,18.基金项目
国家自然科学基金项目(42172166) National Natural Science Foundation of China,No.42172166 （42172166）
