沉积学报2025，Vol.43Issue(3)：846-859,14.DOI:10.14027/j.issn.1000-0550.2024.081
基于沉积动力学的潮控三角洲沉积数值模拟研究
Numerical Simulation of Tidal Delta Sedimentation Based on Sedimentary Dynamics
摘要
Abstract
[Objective]Delta is not only an important part of sedimentological research,but also an important oil-gas enrichment layer in oil and gas exploration.The formation and development of deltas are completed by two or three sedimentary processes in rivers,tides,and waves simultaneously.With further research,tidal-controlled deltas have gradually become important targets for oil and gas exploration and sedimentary studies.However,owing to the influence of hydrodynamics,the distribution patterns of sediment bodies in tidal-controlled deltas are unclear,the sedimentary facies combinations are diverse,and the sedimentary systems and characteristics are complex,leading to significant differences in understanding the sedimentary characteristics and deposition models of tidal-controlled deltas.For the study of tidal-controlled deltas,traditional methods often lack field exposures,face difficulty in sedi-mentary dissections,and have low resolution logging interpretation data,resulting in a certain degree of bias in the understanding of tidal-controlled deltas.The application of numerical simulation method for sediment deposition is ex-pected to solve the above problems.[Methods]To address these issues,sediment numerical simulation methods(Delft3D)were used to establish an idealized tidal-controlled delta model.By varying the conditions of river flow and tidal amplitudes,the study explored the evolutionary patterns and main control factors of tidal-controlled deltas.Al-though the hydrodynamic equation model used by Delft3D is smaller in simulation speed and spatiotemporal scale,it can more accurately describe the deposition process and meet the needs of simulation.This simulation model refers to tide-controlled deltas such as Ganges River Delta,which is used as the reference condition of sedimentary environ-ment to determine the main parameters of the model.After the preliminary test and simulation of the parameters,the parameters were reasonably estimated,and the basic model and the corresponding set of parameter system were estab-lished,completing the model establishment.Furthermore,to explore the influence of the two variables of river dis-charge and tide on the development of the tide-controlled delta,the two variables of river discharge and tide ampli-tude were appropriately enlarged and reduced,and the dam body morphology and delta evolution law were observed by comparison and analysis with the basic simulation.[Results]The research results show that rivers and tides play different roles in the formation of tidal-controlled deltas.Rivers transport sediment from the upstream,which accumu-lates at the estuary,while tides transport and deposit sediment from the upstream towards the deep sea,forming sand bars.As the tidal amplitude increases,the bar body develops into a"flattened shape"towards the ocean.The mor-phology of the bar body and the area of the delta are determined by the river flow and tidal amplitudes.When the river flow and tidal amplitudes increase,their sediment-carrying capacity strengthens,allowing sediment to deposit further from the estuary,increasing the sand bar area.With the increase in tidal amplitudes,the existing bar bodies are eroded and remodeled,transporting the sand bodies towards the ocean,and increasing the average length of the bar body.[Conclusions]The evolution of tidal-controlled deltas can be divided into three periods:sediment accumula-tion at the river mouth;transportation of sediment by river-tidal interactions,forming bar bodies,and rapid delta development;and modification of bar bodies by river-tidal interactions,continued growth of delta area,but with a decreasing growth rate.关键词
潮控三角洲/沉积数值模拟/演化过程/沉积动力学Key words
tidal delta/sedimentary numerical simulation/evolutionary process/sediment dynamics分类
天文与地球科学引用本文复制引用
彭晨阳,唐明明,洪瑞峰,熊思琛..基于沉积动力学的潮控三角洲沉积数值模拟研究[J].沉积学报,2025,43(3):846-859,14.基金项目
国家自然科学基金项目(42072163,41972250)[National Natural Science Foundation of China,No.42072163,41972250] （42072163,41972250）
