一种分子修饰纳米驱油剂的合成与提高采收率机理的研究

Synthesis and Enhanced Recovery of a Molecularly Modified Nano Oil Displacement Agent

研究了纳米二氧化硅粉体的有机表面改性的方法。采用两性表面活性剂十二烷基二甲基氧化胺(OA-12)和硅烷偶联剂的协同作用来对纳米二氧化硅进行改性,分别讨论了反应温度、反应时间、OA-12和硅烷偶联剂的添加量对改性效果的影响。利用红外光谱(IR)、热重(TG)和物理吸附等分析方法对改性前后的纳米二氧化硅粉体进行表征。测定了改性纳米二氧化硅的基本性能,改性合成工艺结果表明,合成纳米二氧化硅驱油剂的最佳工艺条件为:在反应温度为80℃时,0A-12的添加量为3%、前期反应4.5h、硅烷偶联剂的添加量为25%、后期反应3h。改性后的纳米二氧化硅发生润湿反转,由油湿变为水湿,当加量逐渐增加,表面界面张力下降,有利于提高洗油效率;流体黏度增加,有利于提高驱油剂波及体积,由驱油实验可知,质量分数为15%的纳米流体在注入量1PV条件下,原油采收率提高5%以上,具有较好的提高采收率的效果。

Surface modification of nano-SiO_(2) was carried out in solution with 3-methacryloxypropyltrimethoxysilane and amphoteric surfactant dodecyl dimethyl ammonium oxide(OA-12).The structure and performance of modified nano-SiO_(2) were analyzed by infrared spectroscopy(IR),thermogravimetric(TG)and physical adsorption.The influence factors as stirring time,temperature and modifier amount on modified performance were discussed.The results showed that optimal modification conditions with OA-12 and KH-570 were as follow:temperature 80℃,initial reaction time 4.5 h,post-reaction time 3 h,silane coupling agent 25%(mass fraction)and OA-123%(mass fraction).Modified nano-silica changed from hydrophilic to hydrophobic.As an oil-displacing agent,nano-SiO_(2) enhanced the oil recovery via molecular modification and manipulating the interfacial characteristics.