Asphaltene Precipitation inHeavy-Oil Systems

Abstract

Vapor-Assisted Petroleum Extraction (VAPEX) is a relatively new and promising method for recovering heavy crude oils in Canada. The technique upgrades the oil in-situ through asphaltene precipitation, but it may also cause damage to the formation by clogging its pore throats. This thesis brings some clarity to what asphaltenes are and how they form from mixes of bitumen and solvent, depending on the type and amount of solvent used. This was investigated through a series of laboratory experiments where the amount of precipitated solids has been measured at different solvent concentrations. The results are closely linked to asphaltene related production problems and the VAPEX recovery method, which is thoroughly evaluated. Other recovery methods used for heavy oils are also covered, as well as their geological and geographical occurrence, and economic importance for the world’s total oil production. Finally, further work is suggested and future predictions are made.