基于聚焦光束反射测量技术监测稠油乳状液破乳过程

Monitoring the Demulsification Process of Heavy Oil Emulsion Based on Focused Beam Reflectometry

为获得乳状液液滴大小与分布对稠油乳状液表观黏度和稳定性的影响规律,利用聚焦光束反射测量仪(FBRM)考察了温度和剪切速率对辽河油田欢喜岭稠油乳状液液滴平均粒径(简称粒径)大小的影响,动态监测了油包水(W/O)乳状液在加入碱性降黏剂后的破乳行为。结果表明,聚焦光束反射测量技术可以对W/O型乳状液的破乳行为进行良好的动态监测,并可实现对碱性降黏剂最佳使用量的评估。随着温度的升高,油水乳状液液滴粒径增大,乳状液黏度减小;温度低于55℃时,随着剪切速率的增加,乳状液液滴粒径减小,乳状液黏度逐渐变小;当温度高于55℃时,剪切速率对乳状液液滴粒径和黏度的影响较小。在W/O型乳状液中加入Na_2CO_3溶液后,乳状液发生破乳反相,体系黏度降低,小尺寸O/W型乳状液液滴数量增多,粒径减小,液滴分布更加均匀;Na_2CO_3质量分数为0.2%时,乳状液黏度降到最低,乳状液液滴粒径和油水界面张力最小。

In order to obtain the influence of emulsion droplet size and distribution on the apparent viscosity and stability of heavy oil emulsion,the effect of temperature and shear rate on the average droplet size（referred to as droplet size）of Huanxiling heavy oil emulsion in Liaohe oilfield was investigated by using a focused beam reflectometer（FBRM）. The demulsification behavior of water-in-oil（W/O） emulsion after addition of alkaline viscosity reducer was dynamically monitored. The results showed that focused beam reflectometry enabled a good dynamic monitoring of the demulsification behavior of W/O emulsion and an assessment of the optimum amount of alkaline viscosity reducer. With increasing temperature,the droplet size of oil-water emulsion increased,and the viscosity of emulsion decreased. When the temperature was lower than 55℃,the droplet size of emulsion decreased with increasing shear rate,and the viscosity of emulsion decreased gradually. When the temperature was higher than 55℃,the shear rate had little effect on droplet size and viscosity of emulsion. After adding Na2CO3 solution to W/O emulsion,the emulsion emulsified in reverse phase,the viscosity of system reduced,the number of small size O/W emulsion droplets increased,the droplet size decreased,and the droplet distribution was more uniform. When the mass fraction of Na2CO3 was 0.2%,the viscosity of emulsion was the lowest,the droplet size of emulsion and the interfacial tension of oil and water reached the minimum.