碳酸盐台地内下切谷的识别及其意义--以伊拉克H油田上白垩统Mishrif组为例  

Identification of incised valleys in carbonate platform and its significance:taking the Upper Cretaceous Mishrif Formation in H Oilfield,Iraq as an example

作　　者：邵冠铭 乔占峰 曹鹏 张杰[1,2] 孙晓伟 SHAO Guanming;QIAO Zhanfeng;CAO Peng;ZHANG Jie;SUN Xiaowei

机构地区：[1]中国石油杭州地质研究院 [2]中国石油集团碳酸盐岩储层重点实验室

出　　处：《海相油气地质》2022年第1期55-62,共8页Marine Origin Petroleum Geology

摘　　要：碳酸盐台地下切谷的研究多基于阿曼上白垩统露头。以中东地区伊拉克H油田上白垩统Mishrif组钻井岩心、测井和三维地震数据为基础,结合区域层序地层,从沉积旋回、岩相特征、测井响应、地震相平面分布与垂向演化等方面,对碳酸盐台地发育的下切谷这一重要沉积微相类型开展研究,并对其意义作了探讨。研究表明:①H油田MB2-1亚段发育碳酸盐台地内下切谷。下切谷内部以泥晶灰岩充填为主(与下伏颗粒灰岩明显不同),颗粒向上变细再变粗;测井曲线具有箱形特点;地震剖面上呈平行—近平行短轴强振幅反射,边界清晰,平面上显示近似河道形态但更平直。②下切谷在SQ_(3)高位域晚期(MB2-1亚段沉积末期)侵蚀成谷,SQ_(4)海侵期快速充填,下切谷的底部代表了区域层序界面。③下切谷切割MB2-1亚段,而且岩性整体致密,可成为油藏的横向隔挡层。碳酸盐台地下切谷的发现,对于层序边界识别、油藏非均质性研究具有重要意义。The research on the incised valley of carbonate platform is mostly based on the field outcrop of Upper Cretaceous in Oman.Based on the drilling cores,logging and 3D seismic data of the Upper Cretaceous Mishrif Formation in H Oilfield of Iraq in the Middle East,combined with regional sequence stratigraphy,this paper studies the important sedimentary microfacies types of incised valley developed on carbonate platform from the aspects of sedimentary cycle,lithofacies,logging response,plane distribution and vertical evolution of seismic facies,and discusses its significance.The research shows that:(1)There is a incised valley in carbonate platform in MB2-1 submember of H Oilfield.The interior of the incised valley is mainly filled with micrite limestone(obviously different from the underlying grainstone),and the particles become thinner then coarser upward.The logging curve of the incised valley has the characteristics of box shape.For the incised valley,the seismic section shows strong amplitude reflection with parallel-near parallel and short axis,and it is similar to the river shape in the plane while more straight with clear boundary.(2)It is eroded into a valley in the late high-stand domain of SQ_(3)(the late sedimentary stage of MB2-1 submember),and rapidly filled with micrite limestone in the transgressive stage of SQ_(4).The bottom of the incised valley represents regional sequence boundary.(3)The MB2-1 incised valley is compact as a whole,which can be a transverse barrier of the reservoir.The discovery of incised valley in carbonate platform is of great significance for the identification of sequence boundary and the study of reservoir heterogeneity.

关 键 词：碳酸盐台地 下切谷 隔挡层 层序边界 白垩系 伊拉克 

分 类 号：TE122.2[石油与天然气工程—油气勘探]