吴起W井区前侏罗纪古地貌特征及其控油作用  

Pre-Jurassic Palaeogeomorphology and Oil-controlling Function in Wuqi W Well Block

作　　者：何永垚[1] 王治玺 马良杰[2] 张长胜 王丹 陈泓竹 李洋洋 HE Yongyao;WANG Zhixi;MA Liangjie;ZHANG Changsheng;WANG Dan;CHEN Hongzhu;LI Yangyang(School of Petroleum Engineering and Environmental Engineering,Yan’an University,Yan’an 716000,China;Institute of Petroleum Exploration and Development of Changqing Oilfield Company,PetroChina,Xi’an 710021,China)

机构地区：[1]延安大学石油工程与环境工程学院,陕西延安716000 [2]中国石油长庆油田分公司勘探开发研究院,陕西西安710021

出　　处：《延安大学学报（自然科学版）》2021年第4期6-10,共5页Journal of Yan'an University：Natural Science Edition

基　　金：陕西省大学生创新创业训练计划项目(S202110719079);延安大学博士科研启动项目(2003/205040121)。

摘　　要：古地形地貌是控制鄂尔多斯盆地上三叠统延长组油气藏类型与分布的主导因素,系统研究前侏罗纪古地貌特征对预测有利区及寻找剩余油分布至关重要。从前侏罗纪古地貌形成背景、恢复方法、单元划分等方面,对吴起W井区前侏罗纪古地貌特征进行了分析,认为构造抬升、河道深切作用是该时期古地形、地貌形成的关键因素和动力;标志层-印模法是恢复该时期古地貌的有效方法;从“源-渠-汇”角度,依据地形高低、结合对古水流、物源作用,识别出了高地、河谷、谷坡、坡嘴和河间丘等5种古地貌单元,其中河谷属于宁陕河谷吴起段,具有四期充填、北东缓、西南陡的“不对称”型河谷结构;吴起W井区前侏罗纪古地貌类型及分布对侏罗系油气藏储、圈、运有显著的控制作用,宁陕河谷在沟通下伏长7烃源岩形成延安组油藏过程起关键作用,促成研究区西南高地带、谷坡带成为油气富集带。Palaeogeomorphology is the dominant factor controlling the type and distribution of oil and gas reservoirs in the Upper Triassic Yanchang Formation of Ordos Basin.Systematic study of pre-Jurassic palaeogeomorphology is essential for predicting favorable areas and finding remaining oil distribution.The characteristics of pre-Jurassic palaeogeomorphology of Wuqi W well block are analyzed and summarized from the formation background,recovery method and unit division of pre-Jurassic palaeogeomorphology.It is considered that tectonic uplift and fluvial downcutting are the key factors and driving forces for the formation of palaeogeomorphology in this period.The marker layer-the impressing method is an effective method to restore the ancient palaeogeomorphology during this period.From the perspective of‘source-channel-sink’,five topographic units,such as ancient terrace,ancient river valley,valley slope,inter river mound and slope-mouth,were identified according to the topography,paleocurrent and provenance.Among them,the valley belongs to the Wuqi section of the Ningshan River valley,with‘asymmetric’valley structure and four filling stages.The types and distribution of pre-Jurassic palaeogeomorphology have significant indigenous control over the reservoir,trap and migration of the Jurassic Reservoirs.The Ningshan River valley plays a key role in the oil accumulation of the Yan′an Reservoir by connecting to the underlying Chang 7 sourcerock,which results in the oil enriched areas around the southwest highlands and valley slopes in the study area.

关 键 词：吴起W井区 前侏罗纪 古地貌 油气控制 

分 类 号：TE121.1[石油与天然气工程—油气勘探]