Toe-to-Heel Air Injection(THAI)

Only one or two planned commercial applications in Canada
Process where by the subsurface bitumen is ignited and supported with air injected from the surface.
As the fire front advances, the heat warms the bitumen, reducing its viscosity and retorting it. In combination, these transformations result in moveable oil that flows towards the producing wells surrounding the ignition area.
Advantages are that subsurface ignition requires no external source of fuel and is better at containing GHG emissions