# Progress on the Application of Nanomaterial Expansion in Oil Displacement
## 1 Introduction  
Nanotechnology focuses on the innovative applications of solid materials from 1 to 100 nanometers in the field of engineering [1]. Since the beginning of the 21 st century, this technology has gradually penetrated into the fields of medicine, food processing, electronic devices, and oil and gas development. In petroleum engineering operations, nanomaterials have enabled multifaceted integrated solutions, spanning wellbore cementation enhancement, drilling fluid rheology optimization, and chemical conformance control improvement [2, 3]. It is worth noting that nanomaterials can greatly enhance the recovery efficiency in tertiary oil recovery processes through mechanisms such as reducing interfacial tension and altering rock wettability [4]. Therefore, nanomaterials have become a research focus in the oil extraction industry [5]. The application of nanofluids in the field of enhanced oil recovery (EOR) has undergone a comprehensive process, spanning from fundamental mechanism exploration to field validation. In 2013, [PERSON] et al. [6] systematically investigated the role of nanoparticles in EOR. Their findings revealed that nanoparticles can significantly enhance oil recovery by altering rock wettability, reducing interfacial tension (IFT), and increasing fluid viscosity. This study established the theoretical foundation for nanofluid application in EOR. In 2018, [PERSON] et al. [7], further validated that nanofluids improve oil recoverythrough the synergistic effects of IFT reduction and viscosity enhancement. That same year, [PERSON] et al. [8], building on previous research, highlighted that nanoparticle size, concentration, and surface properties also influence the effectiveness of oil displacement. Concurrently, [PERSON] et al. [9], through more in-depth research, elucidated multiple mechanisms by which nanofluids enhance oil recovery, including the generation of structural disjoining pressure and improvement of the mobility ratio. In 2019, [PERSON] et al. [10] indicated that nanomaterials like SiO\({}_{2}\) can stabilize fluid stability and improve flow characteristics through mechanisms such as adsorption and precipitation. [PERSON] et al. [11], in their 2020 review, examined the application of SiO\({}_{2}\) and ZnO nanoparticles in altering rock wettability and reducing IFT, emphasizing the crucial role of surface functionalization in nanofluid stability. In 2022, [PERSON] et al. [12] experimentally validated that SiO\({}_{2}\) and Al\({}_{2}\)O\({}_{3}\) nanofluids significantly enhance oil recovery within porous media. They also noted that the thermal conductivity properties of these nanofluids can accelerate energy transfer. [PERSON] et al. [13], in 2023, explored the potential of ionically stabilized nanofluids for use in heavy oil reservoirs. [PERSON] et al. [14] emphasized the application prospects of nanocomposites under complex geological conditions. The application of nanofluids in EOR has progressed beyond the initial exploration phase, with mechanisms becoming well-defined and technologies optimized. Subsequent research has continued to refine these applications. Extensive studies have demonstrated that certain nanomaterials exhibit excellent oil displacement performance while also demonstrating cost-effectiveness. The content of impurities in silica is extremely low and the density is low, which makes it easier to disperse in the oil displacement process and means that it has less impact on the environment [15]. At the same time, its preparation cost is relatively low, suitable for large-scale applications [16]. Research has demonstrated that SiO\({}_{2}\) nanoparticles can attenuate interphase tension, generate multiphase emulsions, and induce wettability alteration, thereby substantially enhancing hydrocarbon displacement efficiency. For enhanced oil recovery (EOR) applications, [PERSON] et al. [17] developed a novel silica-based amphiphilic Janus nanofluid system. At a concentration of 100 mg/L, the incremental oil recovery factor reached 5.74%. Similarly, [PERSON] et al.