稠油水混输海管停输再启动压力预测

为保障海底稠油集输管线的安全停输与顺利启动，以旅大稠油为研究对象，利用Anton Paar Rheolab QC流变仪分析稠油及其乳状液流变特征与再启动力学响应特性，通过SPSS软件，对正交启动实验数据进行非线性回归分析，建立四参量七系数的启动应力模型；自主研制了室内环道再启动实验装置，分析停运管线在不同工况下启动压力的变化规律，将基于启动应力模型的再启动压力预测值与实测值相比较，评估其预测可靠性。结果表明，稠油乳状液初始启动应力随时间的变化可分为3阶段，即启动应力上升阶段、衰减阶段、平衡阶段；再启动压力预测值与实测值平均相对误差绝对值为16.38%,再启动压力随温度升高而降低，随启动流量升高而升高，适当升高启动流量能减少管线启动时间，但将伴随着再启动压力的升高。

Prediction of restarting pressure of shut-down offshore pipe for heavy oil-water mixed transportation

To ensure the safe shutdown and smooth start-up of heavy oil gathering and transportation subsea pipeline, taking LD heavy oil as the research object, the rheological characteristics and mechanical response characteristics of restart for heavy oil and its emulsion were analyzed by Anton Paar Rheolab QC rheometer. The orthogonal start-up experimental data were analyzed by SPSS software, and a start-up stress model with four parameters and seven coefficients was established. An indoor loop restart experimental device was developed to analyze the variation of the start-up pressure of the shutdown pipeline under different working conditions. The predicted value of restart pressure based on the start-up stress model is compared with the measured value to evaluate the reliability of the prediction. The results show that the changes of initial start-up stress of heavy oil emulsion with time can be divided into three stages, including rising stage, declining stage and equilibrium stage. The average absolute relative error between the predicted value and the measured value of the restart pressure is 16.38%. The restart pressure decreases with the increase of temperature and increases with the increase of start-up flow rate. And with the increase of flow rate properly can shorten the start-up time, but also can enlarge the restart pressure at the same time.