The influence of ionic strength on transport and retention of hydroxyapatite nanoparticles through saturated porous media under reservoir conditions

Abstract

Nanomaterials are widely used in daily life due to their outstanding properties. Nanoparticles (NPs) will unavoidably discharge and migrate across the environment throughout their whole life cycle. The destiny and behaviour of NPs in porous media, as well as the co-transport of NPs with other contaminants, have thus received a lot of interest. Despite their environmental friendliness, hydroxyapatite nanoparticles (HAP) have been used in few EOR studies. Hence, EOR applications must include HAP transport, retention, and adsorption on rock surfaces. Salinity affects NPs behaviour in porous media and EOR applications. Particle adsorption on rock surfaces at distinct ionic strengths impacts reservoir NP movement. The effects of electrolyte solutions with monovalent cations of NaCl on HAP transport behaviour through porous media are yet to be examined. HAP was synthesised and functionalized in situ using sodium dodecyl sulphate (SDS). FTIR and XRD confirmed HAP synthesis, while zeta potential analysis was used to measure its stability. HAP was transported through sandstone cores at varied ionic strengths. The viscosity of brine was examined at varied concentrations and temperatures before utilising it in nanofluid (NF) formulations. XRD, SEM, FESEM, and EDX were utilised on sandstone cores before and after flooding to assess NP adsorption and retention. Breakthrough curves were used to access the transport and retention of HAP through sandstone. Ultimate nanoparticle (NP) recovery is reduced with increase in ionic strength. Permeability measurements before and after NP transport proved that fewer NPs were agglomerated in the rock sample. FESEM, XRD, and EDX results proved that more NPs were adsorbed on the rocks during the transit. An increase in ionic strength causes NP retention to rise, leading to a reduction in NP recovery.