Integration of Natural Seaweed-Derived Polymers and Nanoparticles for Enhanced Oil Recovery

Abstract

This study investigates the use of a carrageenan-based polymer extracted from red seaweed combined with silicon dioxide (SiO₂) and aluminum oxide (Al₂O₃) nanoparticles as a green hybrid chemical system for enhanced oil recovery under Caspian Sea reservoir conditions. The research focused on reservoir conditions of 55 °C and 15,000 ppm NaCl. The seaweed-derived polymer was extracted using an acid-assisted ultrasonic process and prepared at different concentrations, with 1.5 wt% selected as the optimal polymer concentration. Hybrid formulations with SiO₂ and Al₂O₃ nanoparticles were prepared at concentrations of 0.1, 0.2, and 0.5 wt%. The formulations were characterized using ATR-FTIR spectroscopy, XRD analysis, zeta-potential measurements, rheological testing, and tertiary core flooding experiments on Berea sandstone core plugs.

The results confirmed that the extracted polymer was κ-carrageenan. Hybrid formulations showed improved thermal and salinity viscosity retention compared to the pure seaweed polymer. Core flooding experiments demonstrated that Seaweed+SiO₂ achieved the highest incremental oil recovery of 22.7% OOIP, followed by Seaweed+Al₂O₃ with 17.7% OOIP and pure seaweed polymer with 15.6% OOIP. Total cumulative recoveries were 74.3%, 71.6%, and 67.1% OOIP, respectively. Overall, the results demonstrate the technical feasibility of using seaweed-derived carrageenan combined with metal oxide nanoparticles as an environmentally friendly chemical EOR system for high-temperature and high-salinity Caspian Sea reservoir conditions.