Asphaltene Stabilization in Alkyl Solvents Using Oil-Soluble Amphiphiles

Abstract

ABSTRACT Asphaltene plugging is a known cause of near well-bore formation damage. The stability of asphaltenes is predominantly controlled by the thermodynamic state of crude oil. Changes of temperature, pressure and compositions of crude oil can result in the precipitaion of asphaltene components. In this study, the stability of asphaltenes in alkane solvents was investigated using a series of alkyl benzene-derived amphiphiles. The results indicate that the effectiveness of amphiphiles on asphaltene stabilization are strongly influenced by their chemical structure, including the polarity of head groups, the length of alkyl tails and the existence of extra polar groups. These results also provide the information about the interactions of asphaltenes and resin molecules in the crude oil. The small-angle X-ray scattering technique was used to investigate the physical structure of asphaltenes in the amphiphile/alkane solutions. The results indicate that solubilized asphaltenes can interact with each other or with amphiphiles to form associated colloids. The phenomena of precipitation and dissolution of asphaltenes in the porous media was investigated using visual micromodel experiments. In a dissolution experiment, the oil-soluble amphiphile/alkane solutions were proved to be capable of removing asphaltene deposits from porous media.