沉积学报2025，Vol.43Issue(4)：1199-1212,14.DOI:10.14027/j.issn.1000-0550.2024.096
鄂尔多斯盆地西部奥陶纪乌拉力克期岩相古地理特征
Lithofacies Paleogeography of the Ordovician Wulalike Formation,Western Margin of the Ordos Basin
摘要
Abstract
[Objective]The western part of the Ordos Basin was located in the Qilian Sea area during the middle-late Ordovician Wulalike period,when a thick layer of black marine shale developed in the region.Many exploration wells in the Ordos Basin have produced industrial-level oil and gas flows from the Wulalike Formation in recent years,indicating a high potential for further exploration and development of marine shale oil and gas.The study of the Ordovician paleogeography in the western part of the basin is conducive to clarifying the distribution of hydrocarbon source rocks and reservoirs and directing exploration for marine shale gas.[Methods]This paper describes a compre-hensive study of the petrological characteristics,sedimentary facies types and sedimentary evolution of the Wulalike Formation,involving field observation of a large number of outcrops and analyses of drill cores,rock thin sections and elemental geochemical data.[Results](1)The Wulalike Formation comprises a range of rock types:siliceous shale,calcareous shale,clay shale,mixed shale and granular limestone.Of these,laminated siliceous shale was identified as the most favorable lithofacies for shale gas exploration.(2)Four sedimentary facies types from west to east were identified and analyzed:basin facies,broad sea-shelf facies,slope facies and carbonate platform facies.(3)During the Wulalike period,the western Ordos Basin underwent multiple transgression/regressions,and gradual shallowing of the water modified the sedimentary environment.[Conclusions]A model of the carbonate platform mar-gin sedimentation established for the western Ordos Basin in the Wulalike period indicates that the broad sea-shelf fa-cies,slope facies and granular shoal facies favor natural gas exploration in the next step.关键词
鄂尔多斯盆地/乌拉力克组/海相页岩/岩相古地理/沉积模式Key words
Ordos Basin/Wulalike Formation/marine shale/lithofacies paleogeography/depositional model分类
天文与地球科学引用本文复制引用
闫伟,刘洋,郭玮,周黎霞,蔡郑红,黄正良..鄂尔多斯盆地西部奥陶纪乌拉力克期岩相古地理特征[J].沉积学报,2025,43(4):1199-1212,14.基金项目
中国石油天然气股份有限公司"十四五"前瞻性基础性重大科技项目(2021DJ1904) （2021DJ1904）
中国石油长庆油田公司重大科技专项(ZDZX2021)"14th Five-Year Plan"forward-looking and fundamental major science and technology projects of PetroChina,No.2021DJ1904 （ZDZX2021）
Major Science and Technology Special Projects of Changqing Oilfield Company,PetroChina,No.ZDZX2021 （）
