In Changqing oilfield,the pipelines between Jingsi and Jingsan consociation station is vital for the waxy crude oil pipelining.The wax deposition,however,triggers huge economic,safe and efficient problems to the pipeline operation.A series of polyacrylate paraffin inhibitor (WI) with various side chain carbon number distributions were first synthesized by free radical polymerization,and the structural properties and crystallization properties were characterized by using the FTIR and DSC method.Then,the effects of the WIs on the rheological properties of the Changqing waxy crude oil were studied.The results show that after adding 400 mg/kg WI⁃2,the pour point of Changqing crude oil can be reduced by 10 ℃,the anomalous point can be decreased by 8 ℃,and the viscosity of non⁃Newtonian fluid region can be greatly reduced.After that,based on the indoor wax deposition experiment,the influences of the WI on the Changqing crude oil wax deposit properties were studied by settling various conditions and the wax deposition models of Changqing crude oil undoped /doped with WIs were developed.Using the wax deposition models to predict the wax deposit under the field operation condition,it is found that without adding WIs,the prediction error of the wax deposit thickness at different time is less than 5%,and the wax inhibition efficiency can reach 88%~95% after adding 400 mg/kg WI⁃2.