Asphaltenes behavior during petroleum reservoirs acidizing (a molecular-scale onset study)

Abstract

In the present study, we report our findings on asphaltenic sludge formation onset during petroleum reservoir acidizing treatment. To achieve this goal, we perform a series of molecular dynamics (MD) simulations at high temperature and pressure (550 K, 200 bar) on asphaltenic-oil (containing different molecular structures of asphaltenes) /hydrochloric acid (HCl) systems. Our simulation results indicate formation of asphaltenic sludge onset due to reservoir acidizing. Accumulation of the ionized asphaltenes at the oil/aqueous interface is the cause of sludge formation onset. Presence of ionized asphaltenes at the oil/water interface is attributed to the strong ion-ion interaction between ionized asphaltenes and acid ions (H+ and Cl-). Sludge formation onset is further stabilized via hydrogen bonding forces between ionized asphaltenes and interfacial water.