天然气勘探与开发2026，Vol.49Issue(5)：21-33,13.DOI:10.12055/gaskk.issn.1673-3177.20260032
川中古隆起东南部志留系龙马溪组古地貌特征及其形成机制
Paleogeomorphic characteristics and formation mechanism of the Silurian Longmaxi Formation in the southeastern Central Sichuan Paleouplift
摘要
Abstract
The paleogeomorphic pattern during the deposition of the Lower Silurian Longmaxi Formation in the southeastern Central Sichuan Paleouplift is a critical factor controlling the development of shale gas reservoirs in the area.To reveal the paleogeomorphic evolution characteristics and formation mechanisms during this depositional period,this study integrated geological,well-logging,and seismic data to finely restore the paleogeomorphology using the residual thickness method under the constraint of regional isochronous surfaces(i.e.the top and bottom of the S1l1 and the base of the Permian),elucidating the evolutionary process and formation mechanism of the Longmaxi Formation.The following results are obtained.(ⅰ)The paleogeomorphology in the study area generally exhibits a macro-pattern being high in the north and low in the south,governed by the coupling mechanism of differential uplift and basement fault reactivation.(ⅱ)The initially gentle paleogeomorphology was controlled by the continuous uplift of the Central Sichuan Paleouplift,establishing the macro-topographic framework,while the prominent stepped differentiation in the middle-late stages was directly shaped by the synsedimentary reactivation of basement faults triggered by the duyun movement.(ⅲ)The paleogeomorphic evolution controlled the sedimentary environment,which in turn dictated the distribution characteristics of high-quality shales.(ⅳ)The strongly stagnant anoxic environment during the early depositional stage was most conducive to the development and preservation of organic-rich shales(TOC＞3%),whereas in the middle-late stages,intensifying synsedimentary fault activity led to pronounced stepped differentiation and increased terrigenous clastic input,which diluted organic matter and degraded shale quality.It is concluded that integrating paleogeomorphic restoration with tectonic activity analysis to construct a tectonics-paleogeomorphology-sedimentation dynamic model is crucial to accurately predicting favorable shale gas exploration zones in the study area.关键词
四川盆地/川中古隆起/志留系下统龙马溪组/古地貌/阶梯状分异/差异隆升/富有机质页岩/页岩气Key words
Sichuan Basin/Central Sichuan Paleouplift/Lower Silurian Longmaxi Formation/Paleogeomorphology/Stepped differentiation/Differential uplift/Organic-rich shale/Shale gas分类
能源科技引用本文复制引用
罗伟,聂彧晗,石学文,伍秋姿,徐亮,钟可塑,白壮壮,罗超,吴伟,吴喆..川中古隆起东南部志留系龙马溪组古地貌特征及其形成机制[J].天然气勘探与开发,2026,49(5):21-33,13.基金项目
新型油气勘探开发国家科技重大专项项目"四川盆地全油气系统与新领域勘探技术"(编号:2025ZD1400400)、中国石油天然气股份有限公司科技项目"新区新层系有利区优选与勘探评价关键技术研究"(编号:2023ZZ21YJ04). （编号:2025ZD1400400）
