Asphaltene Stability in Crude Oil during Production Process

Abstract

Asphaltene instability may take place in the reservoir leading to permeability damage and contributing to flow restriction issues. It may also occur in production strings and surface facilities causing conduit clogging. Any change in oil composition or pressure and temperature at any stage of production will destabilize crude oil producing asphaltene precipitation. In this study, the stability of target crude oil under the influence of a direct current (DC) is investigated. The amount of the asphaltene deposit and its electrical charge at various operating conditions are investigated. The method consists of applying a DC voltage between two metal electrodes immersed in the crude oil sample. The amounts of deposits accumulated on the surfaces of the electrodes are recorded during experiment time utilizing a miniature two load cells connected to the electrodes. Electric field strength up to 500V is applied. This study confirms that asphaltene colloids are electrically charged. The fact that deposits form on the anode surface proves that asphaltene particles possess a negative charge. The experiment shows that time and potential differences are sensitive parameters. At the first 24 hours, all the asphaltene in the crude oil were extracted. This phenomenon reflects either limited amount of asphaltene exists in the sample, or that the resin content plays a major role in asphaltene colloids charge switch.