含蜡原油蜡沉积影响因素对比试验
Comparison test of factors affecting wax deposition of waxy crude oil
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摘要: 为探究不同蜡沉积因素对大庆原油结蜡规律的影响, 采用单一变量法, 控制不同的结蜡时间、油壁温差、温度区间、剪切速率等影响因素, 利用某新型动态蜡沉积试验装置对大庆原油进行蜡沉积对比试验。结果表明: 当剪切速率一定时, 随着结蜡时间延长, 蜡沉积量逐渐增多, 蜡沉积速率逐渐降低; 当结蜡筒壁温度不变且在析蜡点以下时, 随着油温的升高, 蜡沉积量逐渐增大; 当油壁温差保持不变且温度区间逐渐上升时, 蜡沉积量逐渐减小; 剪切应力与剪切剥离蜡量并非线性关系, 当剪切力达到某一临界值时, 蜡沉积层会被油流冲刷下来。研究结果可为未来含蜡原油管道的输送提供借鉴与技术支持。Abstract: In order to study the influence of different wax deposition factors on the wax deposition law of Daqing Crude Oil, the influence factors such as different wax deposition time, oil wall temperature difference, temperature range and shear rate were controlled with a single variable method, and the comparison test of wax deposition for Daqing Crude Oil was conducted with a new dynamic wax deposition testing apparatus. The results show that: In case the shear rate is constant, the amount of wax deposition will increase with the wax deposition time increase, while the wax deposition rate will decrease. In case the wall temperature of the wax deposition barrel is kept unchanged and lower than the wax appearance temperature, the amount of oil deposition will increase with temperature rising. In case the temperature difference between oil and pipe wall is maintained constant and the temperature range rises gradually, the amount of wax deposition will decrease. For shear stress is of nonlinear relationship with the amount of sheared and stripped wax, the wax deposition will be washed down by the oil flow when the shear force reaches a critical value. The research results could provide reference and technical support for pipeline transportation of waxy crude oil in future.