河流决口扇沉积特征和数值模拟:以内蒙古凉城县东营子扇为例  

Depositional Characteristics and Numerical Modeling of Fluvial Crevasse Fans:Taking the Dongyingzi Fan in the Liangcheng County of Inner Mongolia as an Example

作　　者：张洋 江山[1] 曲洋洋 ZHANG Yang;JIANG Shan;QU Yang-yang(School of Geosciences,Yangtze University,Wuhan 430100,China)

机构地区：[1]长江大学地球科学学院,武汉430100

出　　处：《科学技术与工程》2025年第6期2324-2331,共8页Science Technology and Engineering

基　　金：页岩油气富集机理与有效开发国家重点实验室基金(G5800-18-ZS-KFGY004)。

摘　　要：决口扇的发育过程和演化模式对河流相储层预测和剩余油挖潜具有重要意义。以内蒙古凉城县东营子扇为例,基于卫星影像和野外考察,分析东营子扇沉积特征。利用沉积数值模拟,设置了模拟网格、模拟参数和边界条件,建立了决口扇的数值模型,分析了不同数值模拟阶段决口扇的沉积厚度、河道流速、含砂率平面分布和垂向沉积结构,总结了决口扇的沉积模式、砂体类型和砂体分布。研究表明,东营子扇由决口水道、复合内扇和外扇组成。气候从湿润到干旱的演变过程中,河流决口扇的形成过程可以划分为河流决口期、内扇萌芽期、内扇繁盛期和外扇形成期4个阶段,随着洪水水动力由峰值下降,决口水道、复合内扇和外扇依次形成。复合内扇和外扇是砂岩富集带,是勘探期有利的砂体类型。决口水道是泥岩富集带,是主要的隔夹层类型,周缘的复合内扇是油气田开发后期剩余油富集的主要场所。The sedimentary process and evolutionary model of crevasse fans are of great significance for predicting fluvial reservoirs and remaining oil potential.Taking the Dongyingzi fan in Liangcheng County as an example,based on satellite imaging and field geology,sedimentary features of Dongyingzi fan was analyzed.Using the SFM,the simulation gridding system,simulation parameters,and boundary conditions were designed to establish a numerical model of the crevasse fan.The plane distribution of sedimentary thickness,flow velocity and sand content at different numerical simulation stages were analyzed,as well as vertical sedimentary structure of the crevasse fan.The sedimentary model of crevasse fans was summarized to discuss its significance for Reservoir architecture.Research suggests that the crevasse fans consists of crevasse channels,composite proximal fans,and an distal fans.From a humid to an arid climate,the formation process of crevasse fans can be divided into four stages,which are river crevasse stage,proximal-fan forming stage,proximal-fan flourishing stage and diatal fan forming stage.As the flooding hydrodynamics decreases,crevasse channels,composite proximal fans and diatal fans are formed in sequence.The composite proximal and distal fans are sand-rich area,which are favorable types of sand bodies during the exploration.Crevasse channels are mud-rich area as the main type of interlayer.Composite proximal fans around the crevasse channels is the main site for residual oil enrichment in the later stage of hydrocarbon development.

关 键 词：曲流河 正演模拟 泛滥平原 储层表征 剩余油 

分 类 号：TE122.14[石油与天然气工程—油气勘探]