Removal of asphaltene deposition from well columns: Impact of casing composition

Asphaltene precipitation and deposition in oil reservoirs, wells, transportation, and refineries pose severe problems. Thus, it is important to evaluate its influence by using cutting-edge techniques such as surface treatment. The purpose of the current investigation is to demonstrate how the alteration of casings composition can influence the threshold at which asphaltene can be dislodged from the well column. This can be accompolished by changing surface energy properties. To evaluate the kinetic changes in the removal velocities of asphaltene particles, the intermolecular asphaltene-oil-casing adhesive forces were calculated using the surface energy characteristics of the casings. A study on the experimental size distribution of asphaltene particles was also conducted as a supplement to the theory of surface energy. The mean size of asphaltene particles decreased from 0.6 to 0.4 microns in live oil while the pressure decreased from 5500-4500 psia at 80°C for 260 minutes, before reaching an asumptote. The results showed that particle rebound has a significant impact on the critical velocity of asphaltene removal from the well column which are profoundly influenced by the casing substrate. This can be considered as a viable physical-based surface treatment method to mitigate the deposition of asphaltene in well columns.