水、油接触过程中原油粘度变化的试验研究

应用高温、高压液体粘度装置 ,模拟了水、油接触时地层原油的轻烃组分向地层水中扩散而引起地层原油粘度的变化过程。测定了原油与模拟地层水多次接触后原油粘度与模拟地层水体积数的关系。试验结果表明 ,随着油、水接触轮次的增加 ,甲烷的含量呈下降趋势 ,乙烷和C3 以上组分呈上升趋势。原油粘度变化与油水接触时间有密切关系。随着油水接触时间的增加 ,油中的轻烃组分逐渐扩散到水中并达到平衡状态 ;随着浓度差的减小 ,扩散速度逐渐减慢。原油中轻烃组分溶于水并随地层水产出是导致原油粘度上升的主要原因。这一结果可为水驱油田开发中有效控制原油的粘度、增加水油流度比及提高水驱效率提供理论指导。

Experimental study on viscosity variation of crude oil in oil-water contact process

The viscosity change of crude oil resulted from diffusion of light hydrocarbons from crude oil into water during the process of water displacement was simulated using the high temperature and high pressure fluid viscometer. The effect of simulated formation water on crude oil viscosity after oil water contact was determined. The results show that the change of crude oil viscosity is related with the contact time of oil and water. The light hydrocarbons were dissolved into water and then discharged with water from formation, which was an important reason for the increase of crude oil viscosity during the water displacement process. The study results may be helpful for effectively controlling crude oil viscosity, increasing mobility ratio of water to oil and enhancing water displacement efficiency.