触变性原油管道的停输再启动分析

Analysis of Restart of Thixotropic Crude Oil Pipeline

利用六参数触变模型对触变性原油进行表征分析,并采用数值模拟方法对含蜡原油进行管道再启动分析。结果表明,空白油预剪切温度在凝点以上2℃时,剪切作用对凝点温度下的触变性影响不显著,恒压启动过程中的末端流量以及恒流量启动中的启动压力均接近未剪切的情况;加剂油预剪切温度在凝点以上4℃时,剪切作用对凝点温度下的触变性都有较大影响,启动过程中的关键参数与未剪切情况相比有明显改善。对于添加降凝剂的输油管道,可以设法在停输期间对管内原油进行"扰动",以削弱原油的结构强度,促进管道的再启动安全。

Thixotropic crude oil was characterized by using six-parameter thixotropic model, and the restart of waxy crude oil pipeline was analyzed by numerical simulation. The results show that the effect of shearing on the thixotropy of blank oil sample at freezing point is not significant when the pre-shearing temperature is 2 ℃ above its freezing point, and the terminal flow rate and the starting pressure during the constant pressure start-up are close to those without shearing;the effect of shearing on the thixotropy of the oil sample with pour point depressant at freezing point is significant when the pre-shearing temperature is 4 ℃ above its freezing point, and the key parameters during start-up are improved compared with those without shearing. For the oil pipeline with pour point depressant, it is possible to disturb the crude oil in the pipeline during shutdown to weaken the structural strength of the crude oil and promote the safe restart of the pipeline.