Synthesis of functionalized iron oxide nanocomposites for mitigating fine migration during low salinity water flooding in clay rich sandstones

Abstract The severe permeability impairment caused by clay fine migration remains a critical challenge during low salinity water injection in sandstone reservoirs. The research synthesizes and evaluates a cationic core shell nanocomposite to electrostatically stabilize clay minerals and preserve porous media permeability. A Fe 3 O 4 core was functionalized with chitosan and cetyltrimethylammonium bromide to fabricate the target nanomaterial which was subsequently characterized using advanced spectroscopic and crystallographic techniques. Dynamic light scattering and electrophoretic measurements were utilized to establish colloidal stability and quantify zeta potential alterations while Derjaguin Landau Verwey Overbeek theory calculations modeled the interparticle interaction energies. Core flooding tests were executed on natural clay rich cores to dynamically assess the treating agent. The results indicated that conventional low salinity water injection induced a massive repulsive energy barrier exceeding + 1000 Kbt triggering severe fine detachment and a detrimental permeability collapse of approximately 98%. Conversely the application of the formulated nanofluid effectively neutralized the negative surface charges of the intrinsic kaolinite and quartz grains. This charge neutralization eradicated the repulsive double layer forces and restored a weakly attractive state that anchored the fines to the pore walls. Consequently, the dynamic core flooding demonstrated an exceptional permeability retention with structural damage constrained to a mere 13% to 15%. In summary the synthesized cationic nanocomposite serves as a highly efficient chemical stabilizer that physically and electrostatically mitigates clay induced formation damage ensuring sustained hydrodynamic injectivity for enhanced recovery operations.