Investigating the Impact of Nanoparticles and Nanofluids on the Surface Wettability
Authors: Bahadori Negin , Chen Yun 
Published: February 2024

Abstract
Oil recovery is a critical process of oil production and plays a significant role in meeting the world’s energy demands. As existing oil fields mature and reservoirs become depleted, increasing the recovery rate from hydrocarbon reservoirs becomes more important than ever. The global recovery rate from hydrocarbon reservoirs is currently limited to only one-third of the original oil at place in average, leaving a substantial amount of oil not extracted. By implementing advanced secondary and enhanced oil recovery (EOR) technologies, it is possible to increase the recovery rate beyond current limits. This can alleviate a number of issues related to global energy supply, such as reducing the dependence on aging oil fields. Improving the recovery factor from hydrocarbon reservoirs is therefore essential to maintain a consistent global energy supply and meet the increasing energy demands of the world. Polymer flooding is a well-known chemical enhanced oil recovery (CEOR) process that has been widely implemented. This process mainly operates by lowering the interfacial tension (IFT) of the mineral oil-brine/aqueous chemical and enhancing the viscosity of the injected fluid. However, the effectiveness of polymer flooding is limited by the degradation of polymers caused by chemical, thermal, and mechanical stresses. To overcome this limitation, the approach that combines the benefits of traditional polymer flooding with the advantages of nanotechnology has been proposed in this study. The introduction of nanoparticles enhances the wettability of the rock, which altering reservoir rock wettability from strongly oil wet to water wet. The use of polymers and nanoparticles together has been demonstrated to improve recovery rates beyond those of conventional enhanced oil recovery methods like Surfactant-Polymer (SP) or Alkaline-SurfactantPolymer (ASP). As a result, it can be considered as a viable alternative. Moreover, this technique has economic benefits since the expenses linked with nanoparticles are considerably lower than those connected with surfactant flooding. Hence, this approach has the potential to increase the effectiveness of CEOR processes and raise the quantity of oil recovered.
The objective of this research is to examine the behavior of nanofluids that were prepared using conventional oilfield polymers, with a specific emphasis on their effectiveness in wettability alteration. For this study, the nanofluids consisting of a low concentration of silica (SiO2) and polyacrylamide (PAM), with varying levels of nanoparticle concentration are created. As nanoparticles are introduced into a polymer matrix, they have a tendency to cluster together, forming agglomerates. However, using a lower concentration of nanoparticles can reduce the likelihood of agglomeration and improve the even distribution of nanoparticles within the polymer matrix. As such, and a Drop Shape Analyzer is utilized to measure the contact angle and interfacial tension between the nanofluid and mineral oil system. The findings of this research could enhance the fundamental understanding of the mechanism of wettability alteration via nanoparticles and provide valuable insights into the impact of modifying wettability on oil recovery rates.