基于电中和方法治理弱碱三元复合驱采出液脱水电场失稳

Controlling Electric-field Destabilization Using Charge Neutralization Method in the Separation of ASP Flooding Produced Liquid

碱/表面活性剂/聚合物三元复合驱采出液乳化稳定程度高,影响原油电脱水系统的平稳运行和脱水分离效果。针对这一问题,以聚合氯化铝(PAC)作为电中和调节剂,利用电中和方法治理脱水电场的失稳。实验结果表明,以PAC作为三元复合驱采出液处理调节剂,可降低体系电负性、减小脱水峰值电流、缩短脱水峰值电流持续时间、提高电场的响应性能和采出液脱水率。加入PAC后,采出液脱水率从PAC加入前的95%以下增至平均97.5%以上,且以PAC加量为180~240 mg/L时的电场脱水响应与作用机制发挥最为显著,脱水电流小、维持时间短且变化平稳,脱水后原油含水率控制在0.30%以内、60℃下的污水含油量控制在100 mg/L以内。随着脱水温度的升高,治理效果进一步提升。PAC充分发挥电中和作用机制和静电吸附作用机制,降低体系电负性、削弱油水界面膜强度、提高电场脱水性能,可用于改善弱碱三元复合驱采出液脱水电场失稳的问题。

Alkali/surfactant/polymer(ASP)flooding produced liquid has high emulsification stability,which affects the stable operation and effective dehydration performance of crude oil electric dehydration process.In order to improve this problem,polyaluminium chloride(PAC)was used as a chemical regulator to control electric-field destabilization by charge neutralization mechanism.The results showed that PAC could reduce the electronegativity of the emulsified system,decrease the peak current of dehydration,shorten the duration of peak current of dehydration,improve the response performance of the electric-field,and increase dehydration rate in ASP flooding dehydration process.The dehydration rate of produced liquid increased from below 95%to above 97.5%after adding PAC.When the mass concentration of PAC was from 180 mg/L to 240 mg/L,both the response and mechanism of electric-field dehydration played a significant role during the operation,low current value with short duration and steady change of current were obtained.The water cut in crude oil and oil content in separated water was controlled within 0.30%and 100 mg/L respectively after experiencing dehydration process.Furthermore,the control effect at 60℃was further improved due to the increased dehydration temperature.PAC could be used to improve the problem of electric-field instability in dehydration process for weak-base ASP flooding produced liquid.The electronegativity could be reduced,the oil-water interfacial film intensity could be weakened,and the electric-field destabilization performance could be improved by means of the potential mechanism of charge neutralization and electrostatic adsorption of PAC.