For a while, when I was a student, I had an attic bedroom that was heated by a small coal fire, with a relatively short chimney up to the roof. I learned, fairly early on, that in starting the fire you needed a fairly high velocity air flow across the coals, and underlying firewood strips. And to get this I would rest a shovel over the front of the fireplace, and try and seal off the sides. I kept a small bellows beside the fire to help when this wasn’t particularly successful. When you are starting a fire underground the provision of air is critical, but when you are trying to burn the residual coke that is left, after the heat has cracked the rest of the oil and caused it to flow away, keeping that air flowing at a high enough rate to sustain the high-temperature burn becomes somewhat critical to most efficient operation, particularly if the air has to get through a sand layer to reach the fire. This is the post on THAI – Toe to Heel Air Injection for the recovery of heavy oils, which is part of the ongoing technical post ( tech talk ) series that I write on Sundays. It is a subject that has been described several times in the past at The Oil Drum. I first mentioned it back in 2006 when the first underground test was underway at White Sands. I used this illustration at the time. It is an artist’s impression of a side view of the site, with the blue dotted horizontal line representing the recovery well and air being fed in from a higher well into the formation. The test at White Sands in Alberta has been followed by a test at Lloydminster in Saskatchewan which got underway in a more conventional heavy oil last October. The Kerrobert project followed much on the procedures from the earlier test, and the currently planned full scale production at May River (Large pdf file) Petrobank, which is partnered with Baytex Energy Trust on the 50/50 joint venture, recently sunk two vertical air-injection wells and two horizontal production wells into the extensive Mannville conventional oil reservoir near Kerrobert. Compressed air was added last week after a temporary steaming of the ground to mobilize the oil around the injector site. With the addition of the air, spontaneous underground combustion has begun. “I think we will see some oil as early as today,” Bloomer said. Don and Gail described the THAI process in 2007 and have given some history on its use, THAI having been patented by Petrobank who have a 12 minute video on the process and the first trial and preparation for full scale production. It is well worth watching.

Original Source of The THAI process for bitumen and heavy oil