砂质辫状河中河边滩和河心滩沉积构型:基于沉积演化过程的精细解析  

Sedimentary Architecture Between Compound Middle Bars and Side Bars:Insights from a Numerical Model of Sandy Braided Rivers

作　　者：郭颖[1,2] 冯文杰 李少华[1] 闫淑红[2] Ying GUO;Wenjie FENG;Shaohua LI;Shuhong YAN(School of Geoscience,Yangtze University,Wuhan 430100,China;Sinopec North China Petroleum Bureau,Zhengzhou 450006,China)

机构地区：[1]长江大学地球科学学院,湖北武汉430100 [2]中国石化华北油气分公司勘探开发研究院,河南郑州450006

出　　处：《地球科学进展》2024年第4期405-418,共14页Advances in Earth Science

基　　金：国家自然科学基金项目(编号:41802123,42130813)资助。

摘　　要：心滩是构成砂质辫状河储层的主要沉积单元,受发育位置的影响,存在河心滩和河边滩。由于受到多次侵蚀切割和再沉积作用导致其最终保存的内部构型样式复杂,且二者之间差异不明确。因此,采用沉积数值模拟的方式通过再现河心滩生长与演化过程,解析演化过程中反复的沉积和侵蚀切割的关系,建立二者的内部构型模式,对于指导地下油气精细勘探开发有着重要的实际意义。研究表明:(1)受两侧水流的影响,河心滩的沉积演化是先向下迁移后侧向迁移;而河边滩受单侧水流的影响,沉积演化是先侧向迁移后向下迁移。(2)河心滩自下而上发育顺流加积体、侧积体和垂向加积体,河边滩自下而上由侧积体、垂向加积体或向心充填的河道沉积构成。(3)河边滩比河心滩内部的侧积体期次多,叠切关系复杂。Sandy braided rivers can create extensive oil and gas reservoirs,with channel bars representing predominant sedimentary features.These bars,including compound middle channel bars and compound sidebars,exhibit complex internal architectural patterns resulting from multiple episodes of erosion,cutting,and redeposition during formation.To address these complexities,numerical simulations of sedimentation were employed to replicate the growth and evolution of the bars,enabling the analysis of repetitive sedimentation and erosion-cutting processes shaping their architecture.The results indicate the following:compound middle bars experienced downward migration followed by lateral migration due to water flow from both sides,whereas sidebars underwent lateral migration first and then downward migration due to water flow from one side;②compound middle bars developed through downstream,lateral,and vertical accretions,whereas sidebars formed through lateral,vertical,or infilling deposits,all from bottom to top;and compound sidebars exhibited greater variation in the scale of lateral accretions compared to middle bars,displaying multiple generations and intricate interleaving relationships.A deeper understanding of the internal architecture of middle and sidebars provides novel insights into the characterization of underground oil and gas reservoirs.

关 键 词：沉积数值模拟 河心滩 河边滩 沉积演化 沉积构型 

分 类 号：P618.130.2[天文地球—矿床学]