Sedimentary Numerical Simulation Of Tide-Dominated Esturaine

Estuary,a sedimentary system of fluvial to marine facies transition,is one of the key areas of sedimentological research in recent years.Scholars home and abroad have carried out a lot of studies based on the outcrop and modern deposits.In order to effectively identify the characteristics of estuary interbeds and guide the development of estuary reservoir,it is necessary to study the genetic mechanism of estuary reservoir and the spatial distribution of sand body.For this purpose,this paper setup three groups of Delft3 D models,including the Westerschelde estuary,the theoretical model and the Hangzhou Bay model,based on the hydrology,geology and subsurface characteristics of estuaries from the research of modern deposits and a mass of literature.And simulation results are discussed and analyzed for summarizing the characteristics of hydrology and geomorphology of estuary deposit system,relationship between model and modern deposit,main controlling factors of deposition process,spatial distribution and growth process of esturay sandbody.The experiment shows that:(1)The estuarine deposit simulated by Delft3 D has a good correspondence with modern deposit,hydrodynamic conditions and sedimentary geological and geomorphological characteristics are consistent with the facts.(2)During the process of estuarine deposit,tide is the main controlling factor favorable reservoir formation,such as tidal-bars.Fluvial action promotes the formation of point-bars and damages the tidal-bars,as well,the abundance of sandy sediment is closely related to the viscosity sediment.(3)There are lots of differences between inner and outer estuary on bars deposit models and distribution characteristics.The bars in the inner estuary are more dense,most of them are composite deposits with a small scale and high lateral migration ra,and the interbeds is relatively developed.The distribution of bars in the outer estuary is scattered,most of them are banded or echelon,with wide distribution range and good continuity,but the spacing distance between two bars is large and the interbeds is relatively simple,so it belongs to the favorable reservoir.