Title : Enhanced oil recovery using rectangular silica nanoparticles: An efficiency comparison over commercial spherical nanoparticles
Abstract:
Enhanced Oil Recovery (EOR) methods have traditionally relied on chemical flooding techniques to increase the extraction efficiency of oil reservoirs. Recently, the integration of nanoparticles (NPs) with conventional EOR methods, such as water flooding, has demonstrated significant potential in enhancing oil recovery rates. The effectiveness of these nanoparticle assisted EOR methods, however, is highly dependent on the stability of the nanofluids. Ensuring the stable dispersion of nanoparticles within the flooding medium is crucial for maximizing their effectiveness in altering reservoir properties, reducing interfacial tension, and improving the overall displacement efficiency of the oil recovery process.
More research is needed to optimise NPs’ performance for EOR applications. This study focuses on silica NPs due to their low production cost and environmental friendliness. A primary challenge with silica NPs is their tendency to aggregate in solution due to their ultra-small size and large surface area, which hinders their effectiveness in EOR applications. To address this, silica NPs with a unique rectangular (peanut-like) shape were synthesised. The physicochemical and morphological properties of these NPs were characterised using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Brunauer-Emmett-Teller (BET) surface area analysis, Zeta Potential (ZP), and Dynamic Light Scattering (DLS). The performance of the synthesised rectangular silica NPs was evaluated for EOR applications through contact angle measurements and interfacial tension (IFT) assessments.
A microfluidic setup was constructed to assess the efficacy of enhanced oil recovery at the pore scale, comparing commercial spherical silica NPs with the as-synthesised rectangular silica NPs. This setup allowed for direct visualisation of oil recovery mechanisms after nanofluid injection. Results indicated that the rectangular silica NPs exhibited significantly greater stability compared to commercial spherical NPs, with less size distribution variance.
The IFT measurements revealed a substantial reduction in the presence of rectangular silica NPs, with a 75% IFT reduction compared to only 12% for spherical commercial NPs. Moreover, the rectangular silica NPs improved oil recovery in micro-model tests post-water flooding, showing an approximate 15% increase in recovery compared to a 6% increase with spherical NPs. This enhancement is attributed to better adsorption of rectangular NPs on microchip-pore surfaces, inducing greater structural disjoining forces, detaching oil droplets from surfaces, and altering wettability. In contrast, spherical silica NPs showed notable microchip-plugging due to higher aggregation, which blocked pores and reduced oil recovery. Future research will focus on functionalising the rectangular silica NPs with different agents to further enhance their stability and improve oil recovery efficacy.
Keywords: Enhanced Oil Recovery, Silica Nanoparticles, Nanofluid Stability, Interfacial Tension, Microfluidic Setup, Wettability Alteration.
Audience Take Away Notes:
- Innovative Application of Rectangular Silica Nanoparticles (NPs) in EOR: Understanding the advantages of using uniquely shaped silica NPs over traditional spherical NPs in enhancing oil recovery
- Enhanced Stability and Efficiency: Insights into the stability and performance benefits of rectangular silica NPs, including reduced aggregation and improved interfacial tension reduction.
- Microfluidic Setup for EOR Evaluation: A demonstration of how microfluidic setups can be used to directly visualise and assess the efficiency of nanofluids in EOR at the pore scale
- Wettability Alteration and Structural Forces: An explanation of the mechanisms by which rectangular silica NPs enhance oil recovery through better adsorption, wettability alteration, and the induction of structural forces.
- Future Directions in Nanoparticle Functionalisation: Exploration of potential future research directions, including the functionalisation of rectangular silica NPs to further enhance their stability and efficacy in EOR applications.
- Improved Oil Recovery Methods: Oil industry professionals can adopt more efficient EOR methods, leading to higher oil recovery rates and reduced operational costs
- Enhanced Research Capabilities: Researchers can expand their methodologies to include novel nanoparticle designs and microfluidic testing setups, advancing their experimental capabilities.
- By offering a more stable and effective nanoparticle design, this research simplifies the implementation of EOR techniques, making the designer's job more efficient and reducing the likelihood of nanoparticle aggregation issues.
- The detailed characterisation and performance evaluation of rectangular silica NPs provide valuable data that can improve the accuracy of nanofluid designs for EOR, assisting in overcoming challenges related to nanoparticle stability and efficiency.
