The influence of the adsorption of amphiphiles and resins in controlling asphaltene flocculation

Amphiphiles are frequently used to prevent asphaltene precipitation in rese rvoir rocks and wellbore tubing. It is supposed that these substances can s tabilize the asphaltenes forming a steric stabilization layer around them. In this study, adsorption isotherms of two amphiphiles (nonylphenol and non ylphenolic resin) and a native resin on asphaltene particles are obtained i n order to analyze the relationship between adsorption and effectiveness of these compounds as asphaltene stabilizers. The comparison of the three iso therms reveals a significant difference between the adsorption behavior of the amphiphiles and the resin fraction in terms of the shape of the isother m. Nonylphenol and nonylphenolic resin adsorption isotherms show an LS-shap e that can be explained using an adsorption mechanism in two steps. The ads orption isotherm of the native resin can be explained by penetration of the micropores of the asphaltene particles by resin molecules. There were foun d significant differences in the activity of the studied compounds as aspha ltene precipitation inhibitors that can be linked to the adsorption behavio r of these species. In particular, the native resins seem to show an activi ty stabilization mechanism different than that found for the other species studied.