Enhanced oil recovery (EOR) processes are applied to recover trapped or residual oil in the reservoir rocks after primary and secondary recovery methods. Changing the wettability of the rock from oil-wet to water-wet is named wettability alteration. It is an important factor for EOR. Due to their unique properties, nanoparticles have gained great attention for improving oil recovery. Despite the promising results, the main challenges of applying nanoparticles are related to the colloidal stability of the nanofluids in the harsh conditions of the reservoirs. In recent years, polymer-grafted nanoparticles have been considered as novel promising materials for EOR. The obtained results showed that adding a hydrophobic agent trimethoxy (propyl) silane on the surface of modified silica nanoparticles with polyethylene glycol methyl ether has an effective role in improving retention and wettability alteration, especially in the oil-wet substrate due to hydrophobic interaction. The modified silica nanoparticle by mixed polyethylene glycol methyl ether (Mn ~ 5000) and trimethoxy (propyl) silane showed a proper performance at a concentration of 1000 ppm and a salinity range of 2000–40,000 ppm. The obtained findings can help for a better understanding of the silica nanofluid modification with both hydrophilic and hydrophobic agents for the EOR application of near-wellbore.

强化采油（EOR）工艺应用于一级和二级采收方法之后的储层岩石中残留油或残余油的采收。将岩石的润湿性从油润湿变为水润湿的过程称为润湿性改变。这是提高采收率的重要因素。由于其独特的性能，纳米颗粒在提高采油率方面引起了极大的关注。尽管取得了令人鼓舞的结果，但应用纳米颗粒的主要挑战仍与纳米流体在储层恶劣条件下的胶体稳定性有关。近年来，已将聚合物接枝的纳米颗粒视为EOR的新型有前途的材料。所获得的结果表明，在具有聚乙二醇甲基醚的改性二氧化硅纳米颗粒的表面上添加疏水剂三甲氧基（丙基）硅烷对改善保留率和润湿性变化具有有效作用，尤其是由于疏水相互作用而在油湿基质中。由聚乙二醇甲基醚（Mn〜5000）和三甲氧基（丙基）硅烷混合而成的改性二氧化硅纳米颗粒在浓度为1000 ppm和盐度范围为2000–40,000 ppm时表现出适当的性能。获得的发现可以帮助更好地理解用于近井EOR应用的亲水和疏水剂对二氧化硅纳米流体的改性。由聚乙二醇甲基醚（Mn〜5000）和三甲氧基（丙基）硅烷混合而成的改性二氧化硅纳米颗粒在浓度为1000 ppm和盐度范围为2000–40,000 ppm时表现出适当的性能。获得的发现可以帮助更好地理解用于近井EOR应用的亲水和疏水剂对二氧化硅纳米流体的改性。由聚乙二醇甲基醚（Mn〜5000）和三甲氧基（丙基）硅烷混合而成的改性二氧化硅纳米颗粒在浓度为1000 ppm和盐度范围为2000–40,000 ppm时表现出适当的性能。获得的发现可以帮助更好地理解用于近井EOR应用的亲水和疏水剂对二氧化硅纳米流体的改性。