Nanofluids In Enhanced Oil Recovery Research Articles

On the role of disjoining pressure in nanofluid-assisted enhanced oil recovery: a mini-review.

Nanofluid application in enhanced oil recovery (EOR) recently emerged and garnered significant attention within the field. Nanofluids possess unique properties of reducing oil-water interfacial tension, stabilizing emulsions, altering rock surface wettability, and enhancing disjoining pressure between crude oil and rock surfaces, therefore have potential for the oil recovery process. This review provides an in-depth exploration of various aspects related to nanofluids in EOR. Different types of nanofluids are presented with their preparation methods and representative properties. More importantly, the disjoining pressure, a key physical concept in nanofluid-assisted EOR, is introduced and discussed in terms of the mechanism of oil displacement and measurement methods. Further understanding the role of disjoining pressure in nanofluid-assisted oil displacement is necessary for the development and application of effective nanofluids for EOR.

Research progress and prospect of silica-based polymer nanofluids in enhanced oil recovery

Abstract In recent years, silica-based polymer nanofluids (NFs) have attracted more and more attention because they can enhance temperature and salt tolerance. This study summarized the research progress and prospects of silica-based polymer NFs in enhanced oil recovery (EOR). First, the synthesis method and the effect on silica-based polymer NFs were studied. Research progress in rheology, wettability, viscoelasticity, interfacial tension, adsorption, porous media flow, and emulsion stability were reviewed, and the mechanism for EOR was expounded. Then, the mechanical properties of silica-based polymer NFs and the interaction between silica and polymer were discussed by molecular dynamics simulation. And the progress of research on macroscopic reservoir simulation was explored. Finally, the related auxiliary technologies were introduced, and future research directions were put forward. The results of this study will help researchers better understand the mechanism and research progress of silica-based polymer NFs in EOR.

Displacement dynamics of trapped oil in rough channels driven by nanofluids

It is well accepted that nanofluids have great potential in enhanced oil recovery (EOR). However, the EOR mechanisms by nanofluids largely remain elusive. In the study, the displacement dynamics of residual oil trapped in rough channels by different nanofluids under varied injection pumping forces are investigated by atomistic modeling. Our results indicate that both hydrophilic nanoparticles (NPs) and Janus NPs have highly obvious oil displacement effects. Specifically, hydrophilic NPs increase the viscosity and enlarge the sweeping scope of injected fluid, while Janus NPs favor either staying at the oil–water interface to reduce the interfacial tension or adsorbing onto the convex surface. Under the drag of the injecting flux, Janus NPs displace trapped oil molecules and alter the local surface wettability by sliding along the surface. In contrast, hydrophobic NPs are prone to migrate into the oil phase, which not only reinforces the trapping effect of the oil molecules by the rough surface but also poses a risk of channel blockage. Despite that the oil displacement effect of all the injection fluids is found to be less significant with low pumping force, the Janus NPs are able to maintain a stable oil displacement performance under low pumping force thanks to their sufficiently long contact time with the oil phase. Furthermore, analysis on capillary number indicates that Janus NPs have outstanding application potentials in reservoirs under realistic flooding conditions. Our findings provide atomistic insights into the mechanism of nanofluids in EOR and shed light on the selection and optimization of NPs.

Enhanced oil recovery by wettability alteration using iron oxide nanoparticles covered with PVP or SDS

Wetting phenomena have been extensively investigated in treatment of rocks surface in oil reservoirs using nanofluids for enhanced oil recovery (EOR) purposes. Nanoparticles (NPs) have shown their potential in EOR through surface modification, which results in wettability alteration. In our previous study, the synthesized Fe3O4 NPs coated with Ethylenediaminetetraacetic (EDTA) or Sodium Lauryl Sulfate (SLS) showed good results for wettability alteration phenomenon resulting in EOR. In the present study, the same synthesized iron oxide NPs have been covered with new agents of Polyvinylpyrrilidone (PVP) as a hydrophilic polymer or Sodium Dodecyl Sulfate (SDS) as an ionic surfactant using the same experimental technique as before. Full characterization of the modified NPs has been carried out using Field Emission Scanning Electron Microscope (FE-SEM), X-ray Diffraction device (XRD), Transmission Electron Microscopy (TEM), Fourier-Transform Infrared spectroscopy (FTIR), and the Vibrating-Sample Magnetometer (VSM) analysis. The Scanning Electron Microscope (SEM) micrographs and FTIR analysis and Zeta-potential measurements on the treated carbonate-rock surface decorated with the NPs showed strong wettability alteration from oil-wet to water-wet. The effect of various parameters including the concentration of the mentioned NPs in water-based nanofluid, exposure time, pH, salinity, temperature and pressure on wettability alteration of oil-wet carbonate-rock surface was comprehensively investigated by contact angle measurements. Additionally, the imbibition tests were conducted to determine the potential of the nanofluids in EOR at core-scale. Moreover, the stability of nanofluids in the absence and presence of salts was assessed with Zeta-potential measurements. Our final results showed that NPs covered with PVP and or SDS resulted in 16 % and 13 % increase in oil recovery compared to brine alone, respectively.