Three dimensional visualization of solvent chamber growth during the VAPEX processes: An experimental approach using laser

Abstract

VAPEX is a non-thermal process proposed as an alternative to SAGD due to its applicability in thinner reservoirs, advantage of energy efficiency, produced oil quality, and environmental saving. Its high cost caused by the injected solvent, however, requires further efforts to optimize the process. This, in turn, entails a clear understanding of the physics of the process. To acquire this understanding, a 3-D visualization technique was applied to a VAPEX model packed with glass beads. The oil saturated porous media and the solvent injected into the model processed refractive indices matched with the glass beads, which made the model transparent. Laser illuminated the yellow fluorescent dye dissolved in the solvent to distinguish it from the oil. Two high-speed cameras recorded the process from two sides of the model while a laser sheet moved along the model. A dome-shaped solvent chamber with viscous fingering on its top was observed. The injection pressure influenced the size of the chamber especially in the horizontal direction, which was not possible to identify through standard 2-D tests. Also, the solvent spread along the ceiling of the model and then displaced the oil down. The boundary of the solvent and oil was tilted and even curved at different injection rates. Finally, variable injection rate cases were compared with constant rate trials and an optimum operation plan was proposed through the analysis of the production rate, produced oil quality, and 3-D images of the chamber growth.