柴达木盆地格尔木扇河网密度沿程变化规律  

Variation of the Drainage Density of the Golmud Fan in Qaidam Basin

作　　者：王令辉 张昌民[1] 张祥辉 孙家惠 王浩楠 陆嘉琛 吕笑妍 WANG LingHui;ZHANG ChangMin;ZHANG XiangHui;SUN JiaHui;WANG HaoNan;LU JiaChen(LÜXiaoYan 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：《沉积学报》2025年第2期609-621,共13页Acta Sedimentologica Sinica

基　　金：国家自然科学基金项目(42130813)。

摘　　要：【目的】通过研究现代分支河流体系河网平面展布规律,预测地下河流相砂体储层分布,为储层建模提供知识库,指导油气勘探开发。【方法】利用Google Earth、Global Mapper和91卫图助手等地理信息软件,按照等间隔测线对格尔木河流扇河道条数与宽度信息进行采集,并进行河网密度的计算,总结格尔木河流扇河网密度沿程变化规律,分析河网密度主控因素。【结果】(1)河网密度分布特征与河型转换过程一致,可分为近端、中部和远端三个阶段,近端河网密度范围为0.089~0.198,平均河网密度为0.143;中部河网密度范围为0.136~0.190,平均河网密度为0.164;远端河网密度范围为0.164~0.372,平均河网密度为0.254。(2)河网密度受坡度和地貌因素控制,从近端到远端随着坡度降低,平均河网密度逐渐增大;泉线促进河网密度增长,戈壁、沙漠和湖泊使河网密度下降。(3)通过对格尔木河流扇河网密度研究,测量结果可对地下砂体三维地质建模提供数据支持。【结论】河网密度反应了河道宽度在河流扇内沿程变化规律,通过对现代沉积体系范围内河网密度的刻画,可为地下沉积横剖面砂岩密度和砂体面积比提供参考依据。[Objective]By studying the distribution law of the river network plane of modern distributive fluvial system,the reservoir distribution of underground fluvial sand-bodies is predicted,providing a knowledge base for reservoir modeling and guiding oil and gas exploration and development.[Methods]Using modern geographic information software such as Google Earth,Global Mapper,and 91Satellite Map Assistant,the number and width of the Golmud fluvial fan channels were collected using equal interval survey lines,the drainage density of Golmud fluvial fan was calculated,the variation of the drainage density of Golmud fluvial fan was summarized,and the main controlling factors of drainage density were analyzed.[Results](1)The characteristics of the distribution of drainage density are consistent with the process of river-pattern transition;it can be roughly divided into three stages:proximal,middle and distal.The proximal drainage density ranges from 0.089 to 0.198,with an average drainage density of 0.143;the middle drainage density ranges from 0.136 to 0.190,with an average drainage density of 0.164;and the distal drainage density ranges from 0.164 to 0.372,with an average drainage density of 0.254.(2)The drainage density is controlled by slope and geomorphological factors,with the average drainage density gradually increasing as the slope decreases from the proximal to the distal end;spring lines contribute to the growth of the drainage density,whereas the Gobi,deserts and lakes cause the drainage density to decrease.(3)By studying the drainage density of the Golmud fluvial fan,the measurements can provide data support for three-dimensional(3D)geological modeling of subsurface sand bodies.[Conclusions]The drainage density responds to the change rule of the channel width along the course within the river fan.By portraying the drainage density within the range of the modern depositional system,it can provide a reference basis for the density of the sandstone and the area ratio of the sand body on the subsurface deposition

关 键 词：柴达木盆地 分支河流体系 格尔木河流扇 河网形态 河网密度 储层建模知识库 

分 类 号：P512.2[天文地球—地质学]