不同潮差影响的陆架三角洲沉积模式-基于Delft3D数值模拟的启示
- 1. 西南石油大学地球科学与技术学院
- 2. 西南石油大学
- 收稿日期:
2024-07-23
- 网络出版日期:
2025-03-04
摘要: 潮汐营力对海洋陆架三角洲形态规模及分支河道的发育演化具有重要影响，不同幅度的潮差对陆架三角洲坝体及分支河道定量控制机理是当前热点科学问题。本文采用单因素控制的方法，基于Delft 3D水动力模拟软件设置无、小、中、大潮差等四组对照组，分析不同潮差控制下陆架三角洲关键地质体的演化规律。实验结果表明，在无潮汐作用影响时，分支河道的下切深度和宽度随着流动距离增加逐渐减少；而在加入潮汐作用后，分流河道的数量随着潮差的增大而减小，但河道的下切程度及宽度则增加。无潮汐作用时分支河道的宽深比介于2~10之间，在小潮差时宽深比则呈下降趋势直至0，中潮差和大潮差影响下河道宽深比分别对应于0~3和2~4范围。结果表明，潮汐作用有利于增加砂体的宽厚比，且随着潮差的增大，三角洲在平面上的形态变化越稳定；潮汐影响下的三角洲中分支河道的数量显著减少，这主要归因于潮汐在横向上周期性的涌入和退却，它促进了横向河道及潮汐通道的形成。中-大潮差影响下分支河道侧向迁移距离短，分支河道更稳定，坝体相互之间更为孤立，为类似地下沉积体储层构型分析提供重要参考依据。
Shelf delta depositional model influenced by different tidal ranges-Inspiration from Delft 3D numerical simulation
- Received Date:
2024-07-23
- Available Online:
2025-03-04
Abstract: Tidal forces have an important influence on the form and scale of Marine shelf deltas and the development and evolution of branch channels. The quantitative control mechanism of different amplitude tidal ranges on the dam body and branch channels of continental shelf deltas is a hot scientific issue. In this paper, a single factor control method is used to analyze the evolution of the key geologic bodies in the continental shelf delta under different tidal ranges by using Delft 3D hydrodynamic simulation software to set up four control groups: no, small, medium and spring difference. The experimental results show that the downcut depth and width of the branch channel decrease with the increase of the flow distance when there is no tidal effect. When tidal action is added, the number of distributary channels decreases with the increase of tidal range, but the downcut degree and width of distributary channels increase. The width-to-depth ratio of the branch channel ranges from 2 to 10 when there is no tidal action, and decreases to 0 when there is low tidal range. Under the influence of middle tidal range and spring tidal range, the width-to-depth ratio of the branch channel corresponds to 0 to 3 and 2 to 4 respectively. The results show that tidal action is beneficial to increase the broad-to-thickness ratio of sand body, and the delta morphology changes more stable with the increase of tidal range. The number of branch channels in the delta under the influence of tides decreases significantly, which is mainly due to the periodic influx and retreat of tides in the lateral direction, which promotes the formation of lateral channels and tidal channels. Under the influence of middle-spring difference, the lateral migration distance of the branch channel is shorter, the branch channel is more stable, and the dam body is more isolated from each other, which provides an important reference for reservoir configuration analysis of similar underground sediments.
点击查看大图
下载:
