Evaluation of activated carbon as a Pickering emulsion Stabilizer for conformance control at high temperature and Salinity: A Focus on stability and rheology

• Activated carbon particles provide a dual steric hindrance . • Activated carbon particles act as spacers and bridging materials, strengthening the inter-droplet network against thermal and mechanical changes. • Salt ions further contribute to steric hindrance by acting as co-spacers and bridging materials within the network. • Rheological analysis reveals a transition from balanced viscoelastic behavior to gel-like behavior with increasing salt concentration . This study investigates activated carbon as a porous Pickering emulsifier for oil-in-water emulsions in conformance control applications, aiming to enhance emulsion stability under high salinity and temperature without needing additional surfactants or polymers as needed with the conventional Pickering emulsifiers. The stability and rheology of activated carbon emulsions were evaluated under harsh conditions using X-ray fluorescence, FTIR, microscopy, and rheometry. Tests determined the minimum carbon concentration needed for stability, validated by thermogravimetric analysis and droplet size measurements. Results reveal a dual steric mechanism where activated carbon enhances stability by utilizing porous adsorption of oil droplets as physical barrier in addition to surrounding them. Moreover, salt ions act as co-spacers at high salinity and temperature, the increased particle concentration further reinforces the inter-droplet network, offering resilience to thermal and shear stress. This study highlights activated carbon’s potential as an effective Pickering emulsifier for conformance control in extreme reservoir conditions, paving the way for next-generation emulsifiers in industrial applications.