Enhancing Oil Recovery Using Natural Polymers and Nanoparticles: Insights into Flow Behavior and Dispersion Mechanisms

The continuous demand to transition the energy sector toward environmentally sustainable practices has become a primary driver for investigating natural materials. The naturally derived polymers should effectively perform under high-temperature and high-pressure reservoir conditions. This motivated the development of a new hybrid solution incorporating the effectiveness of nanoparticles. However, limited studies have addressed different polysaccharide–nanoparticle hybrids. This study aims to distinguish the rheological behavior of different polysaccharides under reservoir salinity and temperature. The study evaluates the influence of non-metal oxide (SiO₂) and metal oxide (ZnO) nanoparticles on the polysaccharides. Xanthan and flaxseed gum and their NPs hybrid solutions were examined by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) to assess their structure. Rheological performance was tested across 1–1000 s^–1 shear rates, 25–55 °C, and 1000–35,000 ppm of NaCl. The study focused on Berea sandstone core flooding to evaluate oil recovery, pressure behavior, and displacement efficiency. Despite similar initial viscosities, flaxseed required nearly 10 times more concentration than xanthan, confirming the role of biological origin. Xanthan retained 55.3% viscosity with heating, while flaxseed lost 89.6%. Salinity caused a moderate viscosity drop in xanthan, but an erratic effect in flaxseed. SiO2 showed uniform dispersion and enhanced xanthan stability. ZnO is aggregated and poorly bonded. Oil recovery improved by 38.5% in xanthan–SiO₂ and 26.9% in flaxseed–SiO₂ systems. Despite similar initial viscosities, flaxseed required nearly 10 times more concentration than xanthan, confirming the role of biological origin. Xanthan retained 55.3% viscosity with heating, while flaxseed lost 89.6%. Salinity caused a moderate viscosity drop in xanthan, but an erratic effect in flaxseed. SiO₂ showed uniform dispersion and enhanced xanthan stability. ZnO is aggregated and poorly bonded. Oil recovery improved by 38.5% in xanthan–SiO₂ and 26.9% in flaxseed–SiO₂ systems.