Unified wax deposition model

The calculation method of effective wax precipitation content was proposed according to the flow property of crude oil and wax precipitated mechanism.The main factors affecting the wax deposition were selected by using F testing method.The affecting factors include the viscosity of crude oil,shear stress on tube wall,temperature gradient and the dissolved fraction of wax mass on tube wall.The unified wax deposition model was presented by using line correlation method and wax deposition data of 9 kinds of crude oils on flow loop.In the application of this model,the wax deposition experiment on the flow loop was not needed.The wax deposition could be predicted by using viscosity,wax precipitation property and density of crude oil.The wax deposition along the Zhongning-Yinchuan pipeline was predicted by using this unified wax deposition model,instead of the wax deposited experiments on flow loop.The prediction result was compared with the field data.The relative average error is 6.32%.The maximum relative error is 20%.This method can be used to determine the period of pigging.