AN EXPERIMENTAL THEORETICAL APPROACH TO THE ACTIVITY OF AMPHIPHILES AS ASPHALTENE STABILIZERS

Abstract

ABSTRACT The addition of amphiphiles is one of the most frequent approaches used to prevent asphaltene precipitation in reservoir rocks and wellbore tubing. These substances can solubilize the asphaltenes otherwise insoluble under production conditions. The activity of the amphiphiles as asphaltene stabilizers is directly related to the adsorption behavior of the amphiphile on the asphaltene surface. In this study, a semiquantitative description of the adsorption behavior of different amphiphiles is carried out using molecular modeling to characterize the mutual interactions between the amphiphile, asphaltene and solvent. At the same time, flocculation onset measurements using n-heptane as a precipitating agent were carried out to evaluate the experimental activity of the different amphiphiles as asphaltene stabilizers. Two different indexes calculated using the mutual interaction energies amphiphile–asphaltene–n-heptane were used to correlate them with the experimental activity shown by the amphiphiles. The results obtained indicate that the activity of the amphiphiles as asphaltene stabilizers increases, as their adsorption on the asphaltene is more favorable. In fact, the net adsorption energies of amphiphiles on asphaltenes from n-heptane can be used as a good criterion for the selection of asphaltene precipitation inhibitors.