为提高纳米流体驱对油藏的适用性,满足高效开采的需求,设计了一种对温度能动态响应的纳米材料。将温敏性单体异丙基丙烯酰胺(NIPAm)和亲水单体衣康酸(IA)接枝在纳米SiO₂表面制备了温敏型纳米复合材料NIPAm/IA/SiO₂。通过红外光谱、动态光扫射等表征手段研究了NIPAm/IA/SiO₂的化学结构、热稳定性、形貌及粒径。结果表明,NIPAm/IA/SiO₂具有良好的分散性和热稳定性(初始分解温度为310℃),中值粒径为264 nm。当环境温度低于低临界溶液温度(LCST)时,NIPAm/IA/SiO₂呈现亲水性。温敏型纳米流体的润湿作用使岩石表面亲水性增强、毛细管力增大,NIPAm/IA/SiO₂提高采收率主要是通过渗吸作用完成;当温度高于LCST时,NIPAm/IA/SiO₂呈现两亲性,此时岩石表面趋于中性润湿,从而提高了油水两相的流动性,使孔喉中的油更容易被注入流体驱替。

In order to improve the applicability of nano-fluid flooding to reservoir and meet the demand of efficient production,a kind of nanomaterial with dynamic response to temperature is designed.NIPAm/IA/SiO₂,a temperature-sensitive nanocomposite,is prepared through grafting N-isopropylacrylamide (NIPAm) and itaconic acid (IA) onto the surface of nano-SiO₂.The chemical structure,thermal stability,morphology and particle size of NIPAm/IA/SiO₂ are studied by means of infrared spectroscopy,dynamic light strafing and etc.It is indicated by the results that NIPAm/IA/SiO₂ has good dispersion performance and thermal stability (initial decomposition temperature of 310℃),and its median particle size is 264 nm.NIPAm/IA/SiO₂ shows hydrophilic property when the ambient temperature is lower than the low critical solution temperature (LCST).The wetting effect of temperature-sensitive nanofluid enhances the hydrophilicity of the rock surface and increases the capillary force,therefore NIPAm/IA/SiO₂ improves the recovery efficiency mainly through imbibition.NIPAm/IA/SiO₂ shows amphiphilicity when the temperature exceeds LCST.Under this condition,the rock surface tends to be neutral wetting,which increases the fluidity of the oil-water two phases,and makes the oil in the pore throat easier be injected into the fluid to displace.

陈思齐(1998-),女,硕士生,研究方向为化学驱提高采收率,1193902501@qq.com;郑学成(1988-),男,博士,副教授,研究方向为油气田安全环保,通讯联系人,xc.zheng@swpu.edu.cn。