鄂尔多斯盆地西缘冲断带石炭系羊虎沟组沉积特征  

Sedimentary characteristics of Carboniferous Yanghugou Formation in thrust belt on the western margin of Ordos Basin

作　　者：魏嘉怡 王红伟[1,2] 刘刚[1,2] 李涵 曹茜[1,2] WEI Jiayi;WANG Hongwei;LIU Gang;LI Han;CAO Qian(Research Institute of Exploration and Development,PetroChina Changqing Oilfield Company,Xi’an 710018,China;National Engineering Laboratory for Exploration and Development of Low Permeability Oil&Gas Fields,Xi’an 710018,China)

机构地区：[1]中国石油长庆油田分公司勘探开发研究院,西安710018 [2]低渗透油气田勘探开发国家工程实验室,西安710018

出　　处：《岩性油气藏》2023年第5期120-130,共11页Lithologic Reservoirs

基　　金：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“致密气新区新领域资源潜力与富集规律研究”(编号:2021DJ2101)资助。

摘　　要：根据钻井、录井、测井及地震资料,结合岩石矿物特征、古生物化石以及地球化学特征,对鄂尔多斯盆地西缘石炭系羊虎沟组沉积相特征和展布规律进行了系统研究。研究结果表明:(1)鄂尔多斯盆地西缘羊虎沟组岩性以泥岩、炭质泥岩、煤层为主,间夹泥质粉砂岩、砂岩,形成于海陆过渡相沉积环境,沉积期古气候为温暖潮湿气候。靖远组—羊虎沟组沉积期,湖盆水体盐度逐渐增大,古气候从早期的温湿气候向干热气候过渡,沉积环境由早期的氧化环境向中、晚期的氧化—还原环境过渡,相对古水深由小向大过渡,至羊虎沟组沉积晚期,发生快速水退。(2)研究区羊虎沟组以混合沉积为主,发育三角洲—障壁海岸—滨浅海等沉积体系,属于典型的海陆过渡相。韦州—石沟驿地区发育澙湖—障壁岛沉积相带,总体可分为两大区域性海进、海退旋回,下部海进旋回以海湾—潮坪沉积为主,上部海退旋回以三角洲沉积为主。(3)羊虎沟组沉积水体较浅,周边发育三角洲,内部障壁砂坝较发育,形成了有利沉积相带,垂向上靖远组—羊虎沟组为海湾—潮坪—障壁岛—澙湖—沼泽相的区域海进—海退沉积旋回。Based on drilling,logging,logging and seismic data,combined with rock and mineral characteristics,paleontological fossils and geochemical characteristics,the sedimentary facies characteristics and distribution rules of Carboniferous Yanghugou Formation in the western margin of Ordos Basin were systematically studied.The results show that:(1)The Yanghugou Formation in the western margin of Ordos Basin is mainly composed of mudstone,carbonaceous mudstone and coal seams,intercalated with argillaceous siltstone and sandstone.It was formed in a marine and continental transitional sedimentary environment,and the paleoclimate during the deposition was warm and humid.The salinity of the lake basin of Jingyuan-Yanghugou Formation gradually increased,the paleoclimate transited from the early warm and humid climate to dry and hot climate,the sedimentary environment transited from the early oxidation environment to the middle and late oxidation-reduction environment,the relative paleo water depth transited from shallow to deep,and to the late depositional period of Yanghugou Formation,rapid water regression occurred.(2)The Yanghugou Formation in the study area is mainly composed of mixed sediments,developed with delta,barrier coast and shore shallow sea sedimentary system,which belongs to a typical marine-continental transitional facies.Lagoon-barrier island sedimentary facies belt were developed in Weizhou-Shigouyi area,which can be divided into two regional transgression and regression cycles.The lower transgressive cycle was dominated by bay-tidal flat deposition,and the upper regressive cycle was dominated by delta deposition.(3)The sedimentary water body of Yanghugou Formation was relatively shallow,delta was developed around,and internal barrier sand bar was relatively developed,forming a favorable sedimentary facies zone.Vertically,the regional transgression regression cycle change of bay-tidal flat-barrier island-lagoon-swamp facies was developed in Jingyuan-Yanghugou Formation.

关 键 词：相标志 沉积相 海陆过渡相 冲断带 羊虎沟组 石炭系 鄂尔多斯盆地西缘 

分 类 号：TE121.3[石油与天然气工程—油气勘探] P618.13[天文地球—矿床学]