摘要
Fan delta was one of the important sediment types for continental clastic rocks.The fan delta sand body geometrical shape could be forecasted by using numerical simulation method of dynamic model of sediment transport.After mathematic equations of fan delta sand body deposition process were established,simulation conditions were designed for fan delta sedimentation process based on deposition characteristics of modern delta.The length and width of the calculation field were 20 km and 10 km.The flow rate was designed as the most serious flood in 50 years.When simulation process carried through the year 2 000,fan delta sedimentation process reached stabilization state with the largest sand thickness of 39 m,medium sand was the main sediment.By fan delta lithology simulation study,a set of technology about reservoir structure simulation and prediction of fan delta was established.Four sediment units could be identified:underwater distributary channel with an average length-width ratio of 2.68 and average width-thickness ratio of 79.8;debouch bar with average length-width ratio of 2.02 and average width-thickness ratio of 68.2;distal bar with average lengthwidth ratio of 1.65 and width-thickness ratio of 58.3;underwater overflow sedimentation.The correlativity among the sand body geometry parameters was preferable.The experimental results showed that the dynamic model of sediment transportation could better revealed the fan delta development process by using numerical simulation method,and then could forecast the sand body geometrical shape of the fan-delta.