大型陆相坳陷湖盆深湖区前积型地震地层特征及砂体分布规律——以鄂尔多斯盆地陇东地区延长组中段为例  

Progradational Seismic Strata Features and Distribution of Sandstone in the Deep-water Area of a Large-scale Lacustrine Depression Basin:A case study of the middle Yanchang Formation in Longdong,Ordos Basin

作　　者：惠潇[1,2] 侯云超 喻建[3] 龙盛芳 郭懿萱[1,2] 刘永涛 张杰 HUI Xiao;HOU YunChao;YU Jian;LONG ShengFang;GUO YiXuan;LIU YongTao;ZHANG Jie(Research Institute of Exploration and Development,Changqing Oilfield Company,PetroChina,Xi’an 710018,China;National Engineering Laboratory for Low Permeability Oil&Gas-Field Exploration and Development,Xi’an 710018,China;Changqing Oilfield Company,PetroChina,Xi’an 710018,China;Changqing Branch of Geophysical Research Institute,BGP,PetroChina,Xi’an 710021,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 [3]中国石油长庆油田分公司,西安710018 [4]中国石油东方地球物理勘探有限责任公司研究院长庆分院,西安710021

出　　处：《沉积学报》2022年第3期787-800,共14页Acta Sedimentologica Sinica

基　　金：国家科技重大专项(2017ZX05001002)。

摘　　要：鄂尔多斯盆地三叠系延长组发育多套生储盖组合,其中陇东地区是延长组主要的产油区之一。充分利用最新的三维地震资料,结合大量钻井和测井资料,针对研究区广泛发育的前积型地震连续强反射现象,开展地震地层对比划分、沉积演化及砂体展布规律研究。以湖泛期凝缩层对应的地震同相轴作为地层界面的对比标志,将研究区延长组中段划分出7个层序组,表现为震荡性湖退充填沉积特征,沉积单元呈透镜体依次向湖盆中心叠置,每个沉积单元均发育上部三角洲前缘、中部富泥斜坡和下部深水重力流的三段式沉积相组合,砂体主要分布在沉积单元的上部和下部,平面上具有明显的分带特征。本次研究成果与传统等厚地层对比方案存在明显差异,尤其在顺物源方向,单井之间的小层连通性和叠置关系差异较大,其认识更符合震荡性湖退沉积背景,对油田勘探开发更具有指导性。The Triassic Yanchang Formation in the Ordos Basin consists of multiple source-reservoir-cap packages,of which the Longdong is one of the most important oil-producing areas.Progradational continuous strong reflections predominate in the Longdong area seismic profiles.Based on the most recent 3-D seismic data and a large amount of data from drilling,logging and cores,this study emphasized the strata division,sedimentary evolution and sand body distribution of progradational stratigraphic structures.The continuous strong reflections in the seismic profiles corre⁃spond to mudstone more than 10 m thick,indicating condensed sections deposited during periods of lake flooding.These sections divide the strata into seven sedimentary units,each of which overlaps the previous section towards the basin center.Each unit comprises three sedimentary facies:delta front facies in the upper section,mud-rich slope fa⁃cies in the middle,and deep-water gravity-flow facies in the lowest section.The lake basin experienced fluctuating re⁃gressions during deposition of the middle Yanchang Formation.Sand bodies were mainly developed in the upper and lower sections,with banding distribution styles.Unlike the traditional scheme of lithological stratigraphy,there are great differences in lateral correlation of the sand bodies along the source direction,and in spatial distribution and horizontal overlapping relationships,which this study found to be in line with the sedimentary settings of fluctuating regression,thus giving much more guidance for oil field exploration and development.

关 键 词：地震地层 震荡湖退 砂体分布 延长组 鄂尔多斯盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]