CO2-原油体系黏度测定与预测

Viscosity measurement and prediction of CO2-crude oil system

为研究K油田57025井CO2-原油体系黏度变化的特点,采用CO2-原油室内混溶实验的方法测试不同压力、温度和CO2摩尔分数下的混合流体黏度。结果表明:原油黏度随压力的减小而增大,且35℃时黏度对压力变化敏感;随CO2摩尔分数的增大而减小,且黏度的降幅也减小;随温度的升高而减小,且黏度的降幅也减小。现有黏度计算模型计算过程复杂,不能直接反映实验变量对原油黏度的影响,为预测该CO2-原油体系黏度,通过结合吴光焕黏度计算模型和Briggs模型得到适合该体系的黏度计算模型。与现有模型相比,该模型能准确预测黏度与温度、压力和CO2摩尔分数之间的相关关系,计算方便、精度高,平均误差只有6.73%,可用于该CO2-原油体系黏度的计算。

In order to study the characteristics of viscosity change of CO 2 -crude oil system in the Well 57025 of the K oilfield, viscosity of mixed fluid under different pressure, temperature and CO 2 molar content was tested by the CO 2 -crude oil miscible experiment. The results show that viscosity of crude oil increases with the decrease of pressure and is sensitive to the change of pressure at 35 ℃. Viscosity decreases with the increase of CO 2 molar content, and the declining amplitude of viscosity decreases as well. Viscosity decreases with increasing temperature, and the declining amplitude of viscosity decreases as well. Existed calculation model is complicated and cannot directly reflect the influence of the experimental variables on the viscosity of the crude oil. In order to predict the viscosity of the CO 2 -crude oil system, a new viscosity calculation model is obtained by combining the WuGuanghuan model and the Briggs model with the existed model. The new model can accurately predict the correlation between viscosity and temperature, pressure and CO 2 molar content. Besides, it is convenient to calculate with high precision, and its average error is only 6.73%, which is suitable for the viscosity calculation of the CO 2 -crude oil system.