流量变化控制的辫状河心滩演化过程  

Evolution of Bars in Braided Rivers Controlled by Discharge Variability

作　　者：刘警阳 李伟[1,2] 赵文智[1,2,3] 岳大力 束青林[4] 王武荣[1,2] 高建[3] 侯秀林 吴胜和[1,2] Liu Jingyang;Li Wei;Zhao Wenzhi;Yue Dali;Shu Qinglin;Wang Wurong;Gao Jian;Hou Xiulin;Wu Shenghe(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China;College of Geosciences,China University of Petroleum,Beijing 102249,China;Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China;SINOPEC Shengli Oilfield Company,Dongying 257015,China)

机构地区：[1]中国石油大学油气资源与探测国家重点实验室,北京102249 [2]中国石油大学地球科学学院,北京102249 [3]中国石油勘探开发研究院,北京100083 [4]中国石油化工股份有限公司胜利油田分公司,山东东营257015

出　　处：《地球科学》2024年第10期3516-3528,共13页Earth Science

基　　金：国家自然科学基金项目(Nos.42272186,42202109);中国博士后基金项目(Nos.BX20220351,2022M713458,2022M723489)。

摘　　要：流量变化控制辫状河心滩形成演化进而影响心滩内部结构和叠置样式,但目前流量变化控制的辫状河心滩沉积过程与演化特征尚不明确.利用Google Earth软件在全球范围内选取了发育辫状河沉积的13个河段,并在全球径流数据中心(GRDC)中查询整理所选河段的流量数据,通过峰值流量变异系数(CVQ_(p))对心滩演化过程进行研究.结果表明:就流量变化程度而言,(1)低流量变化辫状河(CVQ_(p)<0.4)心滩演化以坝尾沉积和下游迁移为主,高流量变化辫状河(CVQ_(p)>0.4)心滩演化相对快,洪水前后原有心滩易被破坏、改造形成新的心滩,心滩冲裂现象普遍;(2)单一河流内,低流量变化辫状河心滩长宽比分布相对集中,形态较为稳定,易形成相对稳定型辫状河,而高流量变化辫状河心滩长宽比分布离散,形态各异且发育规模变化较大,易形成游荡型辫状河;(3)顺流加积在低流量变化辫状河心滩演化中较常见,因此心滩经过长时间的演化易形成复合心滩,高流量变化辫状河的洪水事件对心滩演化过程影响较强,在时间尺度上心滩演化相对复杂、规律性较差.明确辫状河在不同流量条件下的心滩演化可为辫状河储层的砂体分布预测提供模式指导,也可为古环境重建和古流量恢复提供依据.The discharge variability controls the formation and evolution of braid bars and influences the internal structure and superimposition of braid bars.However,the control of discharge variability on the developments and evolution of braid bars are unclear.Google Earth software was used to selected 13 river reaches with braided river deposits worldwide,and the discharge data of the selected river reaches are collected from the Global Runoff Data Center(GRDC).Then,the coefficient of annual peak discharge variation(CVQ_(p))was used to study the process and evolution of the braid bars.The results are as follow.(1)In terms of the degree of discharge variability,the braid bar evolution of braided river with lower discharge variability(CVQ_(p)<0.4)mainly develops bar tail deposition and downstream migration.In braided rivers with higher discharge variability(CVQ_(p)>0.4),the braid bar evolves relatively fast.Before and after flood event,the original braid bar is easy to be destroyed and transformed into a new braid bar,and the braid bar burst is common.(2)In a single river,the braid bar distribution of length to width ratio of the braided river with lower discharge variability is relatively concentrated,and the morphology is relatively stable,which is easy to form a relatively-stable braided river.While braided river with higher discharge variability is easy to form classical braided river because of the scattered braid bar distribution of length to width ratio,different morphology and great changes in development position.(3)Downstream accumulation is more common in the evolution of braid bar with lower discharge variability,so it is easy to form compound bars after long time evolution.The flood events of braided rivers with higher discharge variability have a strong influence on the evolution process of the bars,and the braid bar evolution is relatively complex and has poor regularity in the time scale.Clarifying the evolution of braid bars under different discharge conditions can provide guidance for the prediction of

关 键 词：辫状河 流量变化 洪峰流量 心滩演化 沉积模式 石油地质学 

分 类 号：P512[天文地球—地质学]