长庆联合站间管线添加防蜡剂后的蜡沉积特性

长庆靖四至靖三联合站站间管线是靖安油田重要的外输含蜡原油管道。管线内壁蜡沉积给管道经济、安全、高效的运行带来了严峻的考验。首先制备了一系列的聚丙烯酸酯类防蜡剂，考察了防蜡剂的结构与结晶特性及其对长庆原油的流变性改善效果。结果显示，在添加400 mg/kg WI⁃2防蜡剂后，长庆原油凝点可下降10 ℃，反常点可下降8 ℃，非牛顿流体区黏度大幅降低。基于室内环道蜡沉积实验，研究了添加防蜡剂对长庆原油在不同管输条件下的蜡沉积特性的影响，回归了适用于靖四至靖三联合站站间管线的蜡沉积模型，并对现场的蜡沉积情况进行了预测，发现在不添加防蜡剂的情况下，结蜡模型对不同时间内结蜡层厚度的预测误差不超过5%；添加400 mg/kg WI⁃2防蜡剂的防蜡率可达88%~95%。

Wax Deposition Properties of the Pipelines between Consociation Stations in Changqing Oilfield after Adding Wax Inhibitors

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.