控应变流变仪测试含蜡原油的胶凝过程

Waxy Crude Oil Gelling Properties Test by Strain-controlled Rheometer

含蜡原油的粘弹性参数储能模量G′和耗能模量G″可用来表征原油内部结构特征,它们在凝点和倾点附近随温度变化特性能够描述含蜡原油的胶凝特性和流动特性。采用ARES-G2控应变流变仪对大庆原油和马岭原油进行不同温度的应变测试,结果表明:随着应变增大,原油从线性粘弹区过渡到非线性粘弹区,并且线性粘弹区范围随着温度的升高而增大。在线性粘弹区范围内对经50℃恒温热处理的大庆原油和经33℃恒温热处理的马岭原油进行振荡剪切温度扫描,降温速率分别为1℃/min和0.8℃/min,应变为0.5%,频率为1Hz。结果表明:储能模量曲线和耗能模量曲线的两个交点温度可分别用以表征原油的凝点和倾点,且凝点和倾点之间符合线性经验关系。

The viscoelastic parameters storage modulus(G')and loss modulus(G')of waxy crude oil can be used to stand for its inter-nal structure features,and the temperature-dependent characteristic of G' and G' between gelling point and pour point can be adopted to describe(he gel status and flow status of the waxy crude.The result obtained by using the strain testing with different temperature of Daqing crude oil and Maling crude oil with the strain-controlled rheometer ARES-G2 showed that linear viscoelastic region enlarged with the increase of temperature when crude oil turned from the linear viscoelastic region to non-linear viscoelastic region with the strain increased.In the scope of linear viscoelastic region,constant temperature heating at 50 C for Daqing crude oil and at 33 ℃ for Maling crude oil by oscillatory shear test were made.The results showed that the temperature drop rates were 1 'C min and 0 8℃/min separately,the strain was 0.5% and the frequency was 1 Hz.It was concluded that the corresponding temperature of two intersection points of storage modulus curve and loss modulus curve could be utilized to express the gelling point and pour point for the crude oil.and the relationship between the gelling point and pour point obeyed the rule of linear empirical relations.