Study On The Geometry Characteristics And Quantitative Parameters Of Meandering River

The meandering river sand body reservoir is an important type of the continental clastic rock reservoir.With the oilfield development,quantitative analysis of the meandering river sand body has a vital significance of oil and gas exploration and development.This study chooses ten rivers and establish the relationship among the sinuosity,valley slope and channel width.A theoretical function,which links the channel width,the discharge,the sinuosity and the slope,was also constructed based on the Manning equation and evaluated by modern rivers.The growth process and size change of point bar are analyzed under different ranges of sinuosity:when the sinuosity is less than 1.6~1.7,the length of point bar keeps constant and is related to the channel width;when the sinuosity is more than 1.6~1.7,the length of point bar decreases and controlled by both the sinuosity and the channel width.Combining these two functions,the mechanism of river adjustment to the slope variations under a given discharge has been investigated.This adjustment of the sinuosity works in the state of self-organized meandering rivers.With the slope increasing,the channel curves more strongly,and therefore the channel keeps relatively steady with a little widening.There are two situations where this mechanism of adjustment doesn’t work: ⅰ)for an unorganized meandering river,the channel width is deduced to be dramatically narrowing with the continuous increase in the slope,and then the braided river starts.;ⅱ)the slope is too low,and the sinuosity has been 1 or is approaching to 1,the channel widens rapidly.