Pore-scale micromodel experiments for performance evaluation of polymeric nanofluids in CO2 flow through porous media for carbon utilization and storage

Abstract

This study investigated the synthesis and application of carbonated single-step polymeric nanofluids for efficient CO₂ utilization in a subsurface environment. The nanofluids were synthesized using oilfield polymer solutions, ensuring high stability and compatibility with petroleum reservoir conditions such as the presence of crude oil and micromodel studies for CO₂-EOR applications. The work highlights the preparation of nanofluids via a single-step method. Polymers e.g., xanthan gum and polyvinyl alcohol (PVA) were chosen as a base fluid and tetraethyl orthosilicate (TEOS) as a precursor. The nanofluids demonstrated superior stability as evident by visual and zeta-potential results. The average particle of all synthesized nanofluids was in the range of 33–110 nm for xanthan gum-based nanofluids whereas 16.9–115 nm for PVA-based nanofluids. After utilizing the pressure decay method (pressure range: 6–12 bar, ambient temperature: 30 °C), the nanofluids demonstrated exceptional CO₂ absorption capabilities, presenting a promising avenue for carbon capture and utilization. The highest CO₂ absorption was observed for P2 and X1 among all prepared nanofluids as evident from molality results. Higher CO₂ absorption output was also validated by microscopic studies where maximum CO₂ bubbles were observed for P2 and X1. After synthesis, the nanofluids were deployed in a microfluidic unit to simulate subsurface conditions, demonstrating their potential for enhanced CO₂ sequestration. This study presents the novel synthesis of single-step polymeric nanofluids for CO₂ utilization in subsurface environments, with a focus on carbon storage. The study innovatively utilizes a single-step method for nanofluid preparation, enhancing stability and CO₂ absorption efficiency. The findings offer a significant advancement over previous CO₂ sequestration techniques, providing a promising solution for mitigating greenhouse gas emissions.