乌什凹陷神木园地区白垩系舒善河组层序地层及沉积特征  

Sequence Stratigraphy and Sedimentary Characteristics of the Cretaceous Shushanhe Formation in Shenmuyuan Area,Wushi Sag

作　　者：彭坤 周成刚 石鋆秾 刘军 朱梓强 王祖君 朱江坤 张永寿 PENG Kun;ZHOU Chenggang;SHI Junnong;LIU Jun;ZHU Ziqiang;WANG Zujun;ZHU Jiangkun;ZHANG Yongshou(Research Institute of BGP Inc.,PetroChina,Korla Xinjiang 841000,China)

机构地区：[1]中国石油东方地球物理公司研究院,新疆库尔勒841000

出　　处：《科技和产业》2022年第2期365-375,共11页Science Technology and Industry

摘　　要：为厘清乌什凹陷东部白垩系钻井失利原因与油气富集规律,综合应用岩心、测井、三维地震资料,对神木园地区白垩系层序地层特征及沉积相进行研究。结果表明:神木园地区白垩系舒善河组共识别出3个三级层序界面,将舒善河组划分为2个三级层序(SQ1与SQ2),分别对应舒善河组下段和舒善河组上段;识别出4种主要沉积相——辫状河三角洲、冲积扇、扇三角洲及湖泊。结合联井沉积相对比与平面地震相进行沉积体系分析,并以此为依据,研究体系域内沉积相平面展布特征与演化规律,建立沉积模式:在南缘陡坡带主要发育扇三角洲平原(冲积扇)-扇三角洲前缘-滨浅湖沉积体系,在北部长轴缓坡带主要发育辫状河三角洲前缘-滨浅湖沉积体系,西北小物源影响北部长轴物源的岩性组合与物性条件。在层序格架内,应用属性分析、地震反演技术对神木园地区白垩系舒善河组低位域砂体展布进行刻画,结合烃源岩、盖层以及断裂分布特征,认为在纵向上,舒善河组下段为研究区最有利储集层段,舒善河组上段储集性发育较差;在平面上,研究区油气勘探应主要寻找南缘扇三角洲前缘河道砂体、扇间高物性砂体以及北部的辫状河三角洲前缘低位域砂体。To clarify the causes of drilling failures and hydrocarbon enrichment law of the Cretaceous in the eastern Wushi Sag,comprehensively using cores,logging and 3D seismic data,the stratigraphic and sedimentary facies of the Shushanhe Formation,in the Shenmuyuan Area of the eastern Wushi Sag has been studied systematically.Three 3rd order sequence boundaries and two 3rd order sequence(SQ1 and SQ2)are identified in Cretaceous,corresponding to the lower part of the Shushanhe Formation and the upper part of the Shushanhe Formation.Four kinds of sedimentary facies are identified,including braided delta,alluvial fan,fan delta and lacustrine facies.On the basis of sedimentary system analysis by continuous well sedimentation relativity and planar seismic facies,the distribution of sedimentary facies and evolution law in system tracts have been researched,and the depositional model of this period has been built.According to the model,fan-fan delta-lake deposits developed along the steep slopes of the southern margin,while braided delta-lake deposits developed along the gentle slopes in the north of Shenmuyuan area.And the lithological assemblage and physical conditions of the northern long-axis source are influenced by the northwest minor source area.Within the sequence stratigraphic framework,attribute analysis and geophysical inversion have been applied to map the distribution of the lowstand-tract sand bodies of the Shushanhe Formation in the Shenmuyuan Area.Combining hydrocarbon source rocks,cover and fracture distribution features,the lower part of the Shushanhe Formation is considered to be the most favourable reservoir section vertically in the study area,and the upper part of the Shushanhe Formation is poorly developed.Oil and gas exploration in the study area should focus on the high porosity and permeability riverine sands along the southern margin of the fan delta front and the interfan,and the braided-delta front sands in the north.

关 键 词：乌什凹陷 神木园地区 舒善河组 层序地层 沉积相 

分 类 号：TE121.3[石油与天然气工程—油气勘探]