Abstract: Via heating pipelining method, Changqing waxy crude oils with few resins and asphaltenes are transported in Jiangsan-Jinger pipelines, which makes great demands on the safe, economic and efficient pipelining technology. Based on crude oil rheology, physical chemistry and gel chemistry theory, the control stress rheometer was first used to test the complex rheological behaviors of the crude oil, such as viscosity-temperature, yielding, viscoelastic and thixotropic properties. The rheological equation and thixotropic model were then created to fit the Changqing waxy crude oil. Finally, based on the rheological properties, pipeline flow and heat transfer properties, thermal and hydraulic coupling characteristics of the Jingsan-Jinger pipelines, the restart characteristics were forecasted. Results showed that the shear dilution properties became more obvious with the decreasing temperatures below abnormal point; above the pour point, the gelled crude oil showed ductility properties, while below the pour point, it showed a strong brittleness nature, and with the decrease of temperature, yielding stress value increased exponentially; under the constant shear rate, the destruction and reformation of the gel structure occurred in the early 10 min. The prediction of the pipeline restart properties showed that after being shut down for 32 h, pipeline crude oil temperature at the end would drop to the abnormal point; after being shut down for 48 h, pipeline crude oil temperature at the end would drop to the pour point. Considering the safety of pipeline operation, the maximal shutdown time was 32 h, corresponding to the restart pressure of 1.51 MPa.

Key words:  Waxy crude oil pipelines,    , Shutdown and startup,    , Rheological property,    , Yield behavior,    , Viscoelasticity,    , Thixotrop 

摘要：         长庆靖三-靖二联外输管线采用加热输送,所输送的是靖安油田典型的低胶质沥青质含量的高含蜡原油,这对安全、经济、高效的管输工艺提出了很高的要求。基于原油流变学、物理化学和凝胶化学理论,首先使用高精度控制应力流变仪对管道停输条件下,原油体系的黏-温、屈服、黏弹、触变等复杂流变行为进行了研究,然后拟合了适用于该原油的流变方程与触变模型,最后基于原油流变性、管流的流动与传热、热力与水力的耦合特性,对长庆靖三-靖二联管道的再启动特性进行了预测。结果表明,长庆原油在反常点温度以下剪切稀释性也随着温度的降低表现得更为明显。在凝点以及凝点温度以上,原油所形成的胶凝结构表现出一定的延性性质,而在凝点温度以下则表现出很强的脆性性质,并且随温度的降低,屈服值呈指数规律增大。在恒剪切速率的作用下,胶凝结构的破坏和重整发生在初期的10min内。所预测的长庆靖三-靖二联外输管线停输再启动特性,与现场数据相吻合。停输32h后,管道末端原油油温会降至其反常点附近,停输48h后,管道末端原油油温会降至其凝点附近。考虑管道运营的安全性,管道最大停输时间为32h,对应再启动压力为1.51MPa。

关键词: 含蜡原油输送管道,   ,  停输再启动,   ,  流变性,   ,  屈服行为,   ,  黏弹性,    , 触变性