Study of the VAPEX process in fractured physical systems using different solvent mixtures

Abstract

In this work, the vapour extraction (VAPEX) process is studied experimentally in a rectangular physical model at moderate-high pressure. The solvent was either pure propane or a mixture of propane/ methane with different compositions. The solvent and carrier gas were totally mixed before injection, so that a solvent with the desired composition flowed through the injector during experiments, and the solvent mixture was in thermodynamic equilibrium before injection into VAPEX cell. Effects of pressure and composition of solvent were studied. Results showed that at a fixed pressure, the process is more effective with pure solvent compared to the use of solvent mixtures. The main feature of this work is that heavy oil recovery is improved as the approach pressure, defined as the (saturation) pressure minus operating pressure, decreases regardless of solvent composition or operating pressure. These results provide insight into proper field scale implementation of the VAPEX process. Copyright © 2007, Institut français du pétrole.