FAQs

What is VAPEX (Vapour Extraction) and how does it work?

In many heavy oil reservoirs, waterflooding is no longer as productive because water tends to flow under much of the oil in the reservoir and reaches only the oil in the lower portions.  Thus, a vapour is needed to reach the oil that remains stuck in the upper portions of the reservoir. The vapour contacts the oil in the upper parts of the reservoir and thins it, which causes it to flow with the aid of gravity to a lower production well.  

For heavy oil recovery to be effective, the viscosity of the crude oil must be reduced. This can be accomplished by either heating the oil (steam injection) or by blending the oil with a solvent. In the ’80s and ’90s, development of a specific solvent-based process that exploited gravity drainage (an analogue to the well-known thermal process known as steam-assisted gravity drainage or SAGD) was carried out at the University of Calgary under the leadership of Dr. Roger Butler. He coined the term Vapex (Vapour Extraction), which has been branded, for this process.  The Vapex process involves the injection of a vaporized solvent into a horizontal well located in the upper portions of the oil reservoir. The solvent dissolves (by diffusion/dispersion) into the heavy oil reducing its viscosity and creating an expanding solvent vapour chamber. The diluted oil then drains down the edges of the chamber by gravity to a vertically aligned lower horizontal production well where it is pumped to the surface.

Steam is often used for heavy oil extraction because it provides both a vapour and heat to reduce the viscosity of the oil.  Using vapour gas solvents, however, has certain advantages.  To produce the steam, operators must use considerable amounts of energy, which produces greenhouse gases, and enormous amounts of fresh water.  In Vapex, no heat and no water is used.  The solvents are made of hydrocarbons that originally come from oil reservoirs so they are not harmful to the reservoir, and they cannot escape the reservoir.  The solvents are recovered with the oil and recycled, so they are not released to the atmosphere.