沉积与特提斯地质2025，Vol.45Issue(3)：561-580,20.DOI:10.19826/j.cnki.1009-3850.2025.07001
涪陵地区中侏罗统凉高山组二段下亚段岩相特征及其沉积演化
Lithofacies characteristics and sedimentary evolution of the lower submember of Member 2,Middle Jurassic Lianggaoshan Formation,Fuling area
摘要
Abstract
The Middle Jurassic Lianggaoshan Formation in the Fuling area of the Sichuan Basin represents a continental lacustrine basin characterized by complex lithology and strong heterogeneity.The Lianggaoshan Formation,as an important shale oil and gas-producing layer of continental lacustrine basin,requires clarification of its lithofacies characteristics and the evolution process of the sedimentary environment.Taking the lower submember of Member 2 of the Lianggaoshan Formation in the Fuling area as the research object,this study integrates TY1 core observations,logging,data,thin section,paleontological and geochemical indicators to classify lithofacies.Combined with regional drilling data,lithofacies characteristics and transverse correlation research are carried out in the study area to reconstruct the sedimentary environment,identify favorable reservoir development intervals,and analyze its oil and gas geological significance.Eight lithofacies types were identified using the"three-terminal"naming method,including:gray massive sandstone,grayish-white dense shelly limestone,gray sand-laminated siltstone,dark gray low-carbon silty shelly laminated mixed shale,gray to dark gray liquefied deformed sand mudstone interbedded,grayish black medium carbonaceous silt-laminated clay shale,grayish black rich carbonaceous silt-laminated clay shale,dark gray medium carbonaceous silt-laminated clay shale.Lacustrine facies develop in the lower submember of Member 2 of the Lianggaoshan Formation,which can be divided into two sub-facies,shallow lake and semi-deep lake,and can be further subdivided into five sedimentary microfacies.Microfacies characteristics and trace element analysis indicate a warm and humid,paleoclimate and an oxidized to sub-reduced water environment with low salinity.Paleoproductivity was highest in layers ②,③(transitional segment),④(mud shale),and layers ⑥,⑦,and ⑧.Member 2 of the Lianggaoshan Formation records a stage of lake encroachment and water expansion,reaching maximum depth and lateral extent in the middle to lower layer mud shale,where thick,continuous shale developed,favorable for hydrocarbon accumulation.Thus,the lower submember of Member 2 of the Lianggaoshan Formation is conducive to shale oil and gas enrichment and is a favorable interval for shale reservoir exploration in the Lianggaoshan Formation.关键词
涪陵地区/凉高山组/岩相特征/沉积环境/有利储层Key words
Fuling area/Lianggaoshan Formation/lithofacies characteristics/sedimentary environment/favorable reservoir分类
天文与地球科学引用本文复制引用
李闫骥,田景春,郑启明,芦云飞,陈春宇,王道军,梁庆韶..涪陵地区中侏罗统凉高山组二段下亚段岩相特征及其沉积演化[J].沉积与特提斯地质,2025,45(3):561-580,20.基金项目
四川省自然科学基金(2024NSFSC0831) （2024NSFSC0831）
