Abstract

A fan delta sedimentation experiment was conducted through flume equipment, and based on different sedimentation bottom shapes, slopes, water depths, and supply conditions (supply flow rate, sediment concentration, and sediment particle size), the formation and evolution process of fan delta’s delta front sedimentation were simulated. The superimposed pattern of the genesis unit of the front of fan delta was summarized, and the quantitative characteristics of the sand body scale of fan delta’s distributary channel were established. Results indicated that the quantitative scale and relationship of distributary channel’s width-thickness are related with its ability to erode downstream, thus they are also further influenced by several factors such as lake level fluctuation, distance from source, and particle size of sediments in distributary channels. When water depth in lake basin is shallow, the width of the distributary channel is 22-160m, the thickness of the main body is 5-28m, the ratio of width-thickness is 4-8, and the correlation coefficient reaches 0.9382. These research results have important guiding significance for fine description of sand bodies under the condition of few wells in China’s offshore regions.

Keywords:Flume experiments; Fan delta; Genetic mechanism; Distributary channel; Quantitative relationship; Lake level