改性磁性纳米粒子对稠油乳化降黏的影响  

Effect of modified magnetic nanoparticles on emulsified viscosity reduction of heavy oil

作　　者：孙娜娜[1] 柳健 蒋华义[1] 董红妹 胡建波 SUN Nana;LIU Jian;JIANG Huayi;DONG Hongmei;HU Jianbo(College of Petroleum Engineering,Xi'an Shiyou University)

机构地区：[1]西安石油大学石油工程学院

出　　处：《油气储运》2025年第3期311-324,共14页Oil & Gas Storage and Transportation

基　　金：陕西省教育厅重点科学研究计划资助项目“改性磁性纳米粒子的性能调控及其对稠油乳化降粘的微观作用机理”,24JR134。

摘　　要：【目的】乳化降黏技术是解决稠油运输困难常用的方法之一,但传统乳化剂制备的稠油乳状液稳定性较差,在运输过程中容易受外部环境影响导致破乳,研究发现磁性纳米粒子可以促进油水乳状液的稳定性,并且通过外加磁场可以实现循环再使用,而传统的磁性纳米粒子分散性差、沉降快、且对乳状液稳定性的促进效果差,易受外部环境影响。【方法】引入具有负电性与黏弹性的HPAM(聚丙烯酰胺)对磁性纳米粒子Co_(3)O_(4)进行改性,并通过实验探究pH值、乳化温度、油水比等因素对改性前后Co_(3)O_(4)制备的稠油O/W型乳状液稳定性的影响规律与作用机理。【结果】随着pH值升高,乳状液的稳定性增强,且Co_(3)O_(4)@HPAM对乳状液的稳定效果优于Co_(3)O_(4),在pH=10时,4 h后乳状液分水率仅为2.13%。乳状液稳定性发生变化的原因是:随着pH值增大,磁性纳米粒子的Zeta电位绝对值升高,油滴间静电排斥力变大;乳状液表观黏度逐渐增大,油滴运移阻力增强,降黏率逐渐减小,但均在98%以上;油水界面张力降低,有利于磁性纳米粒子吸附在油滴表面;油滴粒径变小、分布更加均匀。随着乳化温度升高,乳状液稳定性变差,当乳化温度为25℃时,4 h后Co_(3)O_(4)@HPAM与Co_(3)O_(4)制备的乳状液分水率分别为25.00%、52.28%;乳状液表观黏度均逐渐减小,降黏率降低,但均大于97%;油水界面膜强度降低,小油滴聚并为大油滴。在油水比小于等于7:3条件下,随着油水比增大,乳状液表观黏度升高,降黏率呈现减小趋势,乳状液稳定性逐渐增强,油滴变小且数量增多;当油水比为8:2时,仅Co_(3)O_(4)@HPAM能够成功制备出O/W型乳状液,4 h分水率为10.25%,降黏率为97.66%。【结论】研究结果充分解释了磁性纳米粒子在不同实验条件下对稠油乳状液稳定性的促进作用,可为磁性纳米粒子在稠油乳化降黏输送技术中的应用提供支持。[Objective]The technology of emulsified viscosity reduction is commonly employed to address the challenges of transporting heavy oil.However,the stability of heavy oil emulsions prepared with traditional emulsifiers is typically low,making them susceptible to demulsification due to external environmental factors during transportation.Previous studies have demonstrated the effectiveness of magnetic nanoparticles in enhancing the stability of oil-water emulsions,and the method of recycling through the application of a magnetic field.Nevertheless,traditional magnetic nanoparticles exhibit poor dispersibility and a high tendency to settle,which limits their ability to enhance emulsion stability and renders them vulnerable to external environmental influences.[Methods]Hydrolyzed polyacrylamide(HPAM),characterized by its electronegativity and viscoelasticity,was introduced to modify Co_(3)O_(4)a type of magnetic nanoparticle.Experiments were conducted to investigate the impact patterns and action mechanisms of various factors,including pH value,emulsifying temperature,and oil-water ratio,on the stability of the O/W emulsions of heavy oil prepared with Co,O4 before and after modification.[Results]The stability of emulsions improved at higher pH values.Co,O@HPAM exhibited a significantly greater impact on emulsion stability compared to Co_(3)O_(4)with a water separation rate of only 2.13%recorded after 4 hours for the emulsion at pH 10.The following factors were identified as contributing to the changes in emulsion stability.As the pH value increased,the absolute value of the zeta potential of the magnetic nanoparticles and the electrostatic repulsive force between oil droplets also increased.This led to a gradual rise in apparent viscosity and enhanced migration resistance of oil droplets in the emulsions,resulting in a steady decrease in the viscosity reduction rate,which,however,remained above 98%.Additionally,the oil-water interfacial tension decreased,facilitating the adsorption of magnetic nanoparticles onto the su

关 键 词：改性磁性纳米粒子 乳化降黏 pH值 温度 油水比 ZETA电位 表观黏度 油滴分布 

分 类 号：TE822[石油与天然气工程—油气储运工程]