experimental analysis of clay swelling and fines migration under varied fluid injection patterns

Formation damage caused by the interaction of injected fluids with clay minerals remains a significant operational challenge in carbonate reservoirs. this experimental study investigates the combined influence of fluid injection patterns and varying ionic compositions on clay swelling (bentonite/ smectite) and fines migration (kaolinite). utilizing synthetic cores and both static (bottle test) and dynamic (core flood) methodologies, the research quantified permeability impairment via the formation damage index (fdi). results conclusively demonstrate that clay swelling is the dominant damage mechanism under aggressive low-salinity injection, causing a significantly higher fdi (27.6%) compared to fines migration (19.8%). furthermore, while polyvalent cations were confirmed to provide superior natural inhibition, the evaluation of chemical additives revealed a functional selectivity: the commercial inhibitor tetramethylammonium chloride (tmacl) effectively controlled swelling, reducing fdi to 11.05%, whereas alumina nanoparticles were ineffective against swelling but showed novel potential for mitigating fines migration. these findings underscore the necessity of developing integrated, multi-stage injection strategies that simultaneously manage ionic strength and apply tailored inhibitors to address the specific combination of swelling and migration damage mechanisms present in a reservoir