稠油-水混输停运管线再启动力学响应特性研究

Dynamic Response Characteristics of Heavy Oil-Water Mixed Transportation Pipeline Restart

为保障海洋稠油集输管线的安全停输与顺利启动,以旅大油田稠油为研究对象,利用Anton Paar Rheolab QC流变仪分析纯油及其稠油-水乳状液流变学特征与初始启动力学响应特性。通过自主研制室内环道再启动实验装置,测量停输管线在不同温度、不同启动流量工况下再启动压力的变化规律,将基于流变仪测试的再启动压力理论值与实测值相比较,评估其预测可靠性。流变实验结果表明:稠油乳状液初始启动应力随时间的变化可分为三个阶段,即启动应力上升阶段、衰减阶段、平衡阶段;启动温度、恒定剪切速率对启动应力的影响作用呈正相关。通过流变仪测量得到的启动应力可用于预测再启动压力,平均绝对相对误差为6.95%,其吻合精度较好。为解决海上无人平台稠油-水停输管线启动、置换自动化实施难题提供了理论依据与数据支撑,对海上高黏稠油管线停输再启动作业及管线设计具有指导作用。

In order to ensure the safe shutdown and smooth start-up of offshore heavy oil production and transportation pipelines,taking Lvda heavy crude oil as research object,the rheological characteristics and initial start-up dynamic response characteristics of heavy oil and heavy oil-water emulsion were systematically analyzed by using Anton Paar Rheolab QC rheometer.The restart pressure of shutdown pipeline at different temperatures and flow rates was measured through laboratory loop restart experimental device developed independently.The theoretical values of restart pressure measured using rheometer were compared with those measured through the laboratory loop restart experimental device to evaluate the reliability of theoretical prediction.The experimental result shows that the start-up process of heavy oil-water emulsion can be divided into three stages:the rising stage,attenuation stage and equilibrium stage of start-up stress.Start-up stress is positively related to start-up temperature and shear rate.The average relative error of the start-up stress measured by rheometer is 6.95%,it can be used to predict the restart-up pressure of pipeline.The research result can provide theoretical basis and data support for restart-up and replacement automation of shutdown heavy oil-water pipelines on unmanned offshore platforms and guidance for restart-up operation and pipeline design of offshore heavy oil pipelines.