..."The THAI™ process combines controlled combustion with vertical and horizontal wells. The simple equation is: air in, upgraded heavy oil out.
To begin the process, bitumen around the “toe” of the horizontal well is heated with steam. Once this approximately three-month heating cycle in a bitumen reservoir is complete, the steam is shut off and air is injected into the vertical well to create a combustion reaction in the reservoir.
Through the controlled injection of air, an estimated two metre thick combustion front begins to move along the horizontal well at about 10 inches (25 centimetres) a day toward the “heel” of the horizontal well. As it heats up, the bitumen drains into the horizontal production well and brought to the surface through natural pressure.
Because the combustion front heats the bitumen to 400 degrees, the oil is also partially upgraded underground. The heat causes a portion of the asphaltine content of the oil to be left behind as coke that is the fuel for the continued combustion.
“It’s an ideal technical solution,” says Chris Bloomer Petrobank’s Chief Operating Officer for Heavy Oil. “Not only does THAI™ allow for a higher recovery of the resource – from 70 to 80 per cent – greenhouse gas emissions are cut by half and there is negligible fresh water use.” Another environmental benefit is a smaller surface footprint and easier reclamation."...........
