鄂尔多斯盆地延长组长9砂体的垂向结构及主控因素分析  

Vertical Structure and Dominating Factors of Chang 9 Sandbody from Yanchang Formation in Ordos Basin

作　　者：赵云翔[1] 陈景山[1] 王建峰[1] 丁熊[1] 姚泾利[2] 李士祥[2] 李宁[3] 

机构地区：[1]西南石油大学资源与环境学院,成都610500 [2]长庆油田公司勘探开发研究院,西安710021 [3]大港油田滩海开发公司,天津300280

出　　处：《沉积学报》2013年第1期77-88,共12页Acta Sedimentologica Sinica

基　　金：四川省重点学科建设项目(编号:SZD0414)资助

摘　　要：近年来随着对鄂尔多斯盆地油气地质条件的重新认识,在上三叠统延长组下部的长9油层组中获得了新发现、新突破,该油层组成为油气勘探重要的战略接替层系。通过露头剖面、钻井、岩芯、测井及分析化验等资料的综合研究,结合沉积古地理背景分析,以沉积特征和指相标志的识别为依据,认为盆地内长9砂体的成因类型主要包括三角洲环境与牵引流作用有关的陆上与水下的分流河道、天然堤、决口扇、三角洲前缘的河口坝、远砂坝、席状砂等砂体,滨浅湖环境与湖浪和湖流改造作用有关的砂质滩坝、席状砂等砂体。根据岩芯剖面精细描述及沉积微相分析,结合测井曲线解释,指出长9单砂体主要发育B、C、I、F、D五种基本垂向结构类型,多层砂体的垂向叠加样式复杂多变,常见的有BB、CC、CB、II、CI、BC、BI、FF等类型。砂体垂向结构的主控因素分析表明,沉积环境、沉积相以及基准面升降旋回是控制单砂体垂向结构、多层砂体垂向叠加样式及分布的主要地质因素。With the re-understanding of hydrocarbon geological conditions in Ordos Basin, a new discovery and break- through have been found in Chang 9 Reservoir Group form the lower part of Upper Triassic Yanchang Formation in re- cent years, and it has become the important succeed layer of strategic exploration. Through comprehensive study of outcrop section, drilling, core, well logging and tests, combining with the background analysis of sedimentary paleo- geography, based on sedimentary characteristics and facies marker, it is considered that the genetic types of Chang 9 sandbody within the basin mainly include onshore and underwater distributary channel, natural levee, crevasse splay, sheet sand and other sandbodies associated with traction current effect in delta environment, the river-mouth bar, dis- tal bar, sheet sand and other sand bodies in delta front, and the sandy shoal and bar, sheet sand and other sand bodies related to lake-wave and lake-flow reworking in shore to shallow lake environment. According to the detailed description of core sections and the analysis of sedimentary microfacies, combined with logging interpretation, it is pointed out that Chang 9 single sand body mainly develops B, C, I, F and D basic vertical structure types and multi- story sandbodies have complicated and variable vertical stacking patterns, with BB, CC, CB, II, CI, BC, BI and FF as the common types. It is indicated that sedimentary environment, depositional facies and base-level fluctuating cycle are main geologic factors controlled on vertical structure of individual sandbody, vertical stacking pattern and distribu- tion of multistory sandbodies from the analysis of dominating factors of vertical structure of Chang 9 sandbodies.

关 键 词：垂向结构 叠加样式 砂体 三角洲 长9油层组 鄂尔多斯盆地 

分 类 号：TE121.3[石油与天然气工程—油气勘探]