Vapex-gravity-assisted film drainage for heavy oil recovery

Reservoir heavy oils of viscosity higher than 20 cp are difficult to recover efficiently. A new vapor extraction process called Vapex which uses horizontal wells and volatile solvents is being developed, primarily in Canada. This process lowers the viscosity of the oil by dilution and the oil is produced by gravity drainage (vertical movement of fluids) to horizontal wells placed low in the reservoir. More oil should be produced at lower production and energy costs. The Vapex process is outlined in this article and followed by some experimental work demonstrating gravity drainage flow in films at the macro- and micro-scale.