低温输送管道稠油粘附能预测模型

A prediction model for heavy oil adhesion energy in low-temperature transportation pipelines

海上和内陆油田集输系统含水率较高(90%以上)产生严重的集输管道原油粘附现象。通过建立以Deriagwin-Landau-Verwey-Overbeek(DLVO)理论为基础,分子间热运动、管流剪切应力、范德华引力(VDW)和双电层静电斥力(EDL)等各作用能项为核心的粘附能预测模型对高含水稠油粘附现象进行了研究,并计算了集油温度(粘附温度),分析了粘附能影响因素,最终对模型进行了验证。结果表明,预测模型中VDW可以促进稠油粘附,而分子热运动、管流剪切应力和EDL可以抑制稠油粘附现象。这些相互作用也受温度、溶液相离子浓度、分离距离和油滴粒径变化影响,可以通过改变这些影响因素来防治稠油粘附现象。粘附温度计算值与粘附温度实验值对比表明,模型计算值误差在2℃以内。本文研究成果可为进一步开展低温输送现场试验提供理论基础与应用指导。

High water content(more than90%)in the gathering and transportation system of offshore and onshore oilfields has led to the serious adhesion of crude oil in the gathering and transportation pipeline.Based on the Deriagwin-Landau-Verwey-Overbeek(DLVO)theory,the adhesion energy prediction model considering the intermolecular thermal motion,pipeline flow shear stress,van der Waals(VDW)force,and electrical double-layer static repulsion(EDL)as the core of the energy terms was established to study the heavy oil adhesion phenomenon caused by high water content.The oil collection temperature(adhesion temperature)was calculated,and the influencing factors of adhesion energy were analyzed.Finally,the model was verified.The results show that VDW in the prediction model can promote heavy oil adhesion,while intermolecular thermal motion,pipeline flow shear stress,and EDL can inhibit heavy oil adhesion.These interactions are also affected by changes in temperature,solution-phase ion concentration,separation distance,and oil droplet size,which can be altered to combat heavy oil adhesion.By comparing the calculated value of adhesion temperature with the experimental value,it is found that the error of the calculated value of the model is less than 2℃.The research results of this paper can provide a theoretical basis and application guidance for further field tests of low-temperature transportation.