Nanofluid-enhanced oil recovery (EOR) technology is an innovative approach to enhancing oil production in oilfields. It entails the dispersion of nanoparticles within a fluid, strategically utilizing the distinctive properties of these nanoparticles (NPs) to engage with reservoir rocks or crude oil, resulting in a significant enhancement of the oil recovery rate. Despite the notable advantages of nanofluid EOR technology over conventional oil recovery methods such as binary and ternary flooding, practical implementations continue to grapple with a range of pressing challenges. These challenges encompass concerns regarding the economic viability, stability, and adaptability of nanomaterials, which pose significant barriers to the widespread adoption of nanofluid EOR technology in the oil field. To tackle these challenges, addressing the current issues may involve selecting simpler and more readily available materials coupled with straightforward material modification techniques. This approach aims to more effectively meet the requirements of large-scale on-site applications. Within this framework, this review systematically explores commonly employed nanofluids in recent years, including inorganic nanofluids, organic nanofluids, and composite nanofluids. It categorizes the research advancements in optimizing modification techniques and provides a comprehensive overview of the mechanisms that underpin nanofluid EOR technology and its practical applications in oilfields. This comprehensive review aims to offer valuable references and serve as a solid foundation for subsequent research endeavors.

The problem of offshore oil leakage has wreaked havoc on the environment and people’s health. A simple and environmentally friendly impregnation method combined with marine mussel bionics was used to address this issue. Using the viscosity of polydopamine (PDA), nano- Fe₃O₄ and WS₂ adhered to the framework of the melamine sponge (MS), and then the magnetic sponge was modified with n-octadecanethiol (OTD), and finally the superhydrophobic magnetic melamine sponge (mMS) was prepared. The modified sponge has superhydrophobicity (WCA, 156.8° ± 1.18°), high adsorbability (40~100 g°g⁻¹), recyclability (oil adsorbability remains essentially unchanged after 25 cycles), efficient oil–water separation performance (>98%), and can quickly separate oil on the water’s surface and underwater. Furthermore, the modified sponge exhibits excellent stability and durability under harsh operating conditions such as strong sunlight, strong acid, strong alkali, and high salt, and can control the direction of the sponge’s movement by loading a magnetic field. To summarize, mMS has many potential applications as a new magnetic adsorption material for dealing with complex offshore oil spill events.

The discharge of oily wastewater and oil spills at sea are the current difficulties in water pollution control. This problem often leads to terrible disasters. Therefore, the effective realization of oil-water separation is a very challenging problem. Superhydrophobic sponge is a promising oil-absorbing material. In this article, we reported a superhydrophobic sponge with nano-Fe₃O₄ for oil-water separation. The addition of nano-Fe₃O₄ allows the sponge to be recycled under the action of magnetic force. The sponge has the advantages of low cost, simple preparation and efficient oil-water separation. This kind of sponge is very worthy of promotion for the treatment of oily wastewater and marine oil spill accidents.

With the intensification of human activities, a large amount of oil and organic solvent waste has been created, resulting in serious ecological and environmental pollution. Therefore, how to balance environmental benefits and economic benefits control a large number of organic solvent and oil pollution is an urgent problem. To solve this problem, a highly efficient oil-water separation material was designed and prepared in this paper. Graphene oxide aerogels were synthesized by the Pickering emulsion and hydrothermal method, and then hydrophobically lipophilic polydimethylsiloxane (PDMS) reduced graphene oxide aerogel composites (PDMS/GA) were obtained by modification of PDMS. The surface functional groups, hydrophobicity, thermal stability, and micromorphology of the materials were tested by various characterization methods. Their properties were tested by an oil absorption test and repeated experiments. The oil absorption performance experiments and repeated performance experiments of PDMS/GA are reported. The number of oxy-gen-containing functional groups of the modified graphene oxide (GO) decreased, and the contact angle of water was 134.4°. The adsorption capacity of n-hexane was up to 18.5 times its own weight. The material has the advantages of being lightweight, easy to recover, good hydrophobicity and lipophilicity, and has the potential for large-scale applications in the field of oil-water separation.

The KCl/PHPA waste drilling fluid is produced during drilling operations in Bohai Oilfield, China, which cannot be directly used or discharged, it needs to be flocculated. In order to know the aggregation mechanism of colloidal particles in KCl/PHPA drilling fluid, the calculation method of zeta potential and the relationship between the stability of waste fluid and zeta potential are discussed in detail in this article. The process of decreasing the zeta potential of waste fluid due to the addition of cationic polyacrylamide is called instability. The process in which unstable particles aggregate into larger particles is called coagulation, and the process in which unstable particles aggregate into large flocs is called flocculation. According to the types of treatment agents in KCl/PHPA waste drilling fluid, the structure and energy changes formed between low-viscosity polyanionic cellulose, partially hydrolyzed polyacrylamide, xanthan gum, starch, and water molecules are constructed. The energy of the four treatment agent systems decreased by 21.4–67.5% after the cationic polyacrylamide was added. The reduction of system energy reduced the repulsive force between colloidal particles in the waste fluid and promoted the agglomeration of colloidal particles. The agglomeration mechanism of waste liquid particles was obtained.

In situ combustion of heavy oil is currently the most suitable thermal method that meets energy consumption and carbon dioxide emission requirements for heavy oil recovery. The combustion catalyst needs to perform multiple roles for application; it should be capable of catalyzing heavy oil combustion at high temperatures, as well as be able to migrate in the geological formation for injection. In this work, a hyperbranched polymer composite nanometal fluid was used as the injection vector for a heavy oil in situ combustion catalyst, which enabled the catalyst to rapidly migrate to the surface of the oil phase in porous media and promoted heavy oil cracking deposition at high temperatures. Platinum (Pt) nanoparticles encapsulated with cetyl-hyperbranched poly(amide-amine) (CPAMAM), with high interfacial activity, were synthesized by a facile phase-transfer method; the resulting material is called Pt@CPAMAM. Pt@CPAMAM has good dispersion, and as an aqueous solution, it can reduce the interfacial tension between heavy oil and water. As a catalyst, it can improve the conversion rate during the pyrolysis of heavy oil in a nitrogen atmosphere. The catalyst structure designed in this study is closer to that exhibited in practical geological formation applications, making it a potential method for preparing catalysts for use in heavy oil in situ combustion to resolve the problem of catalyst migration in the geological formation.