Even with the price of oil unseasonably low, the quest for new forms of energy must forge on. Gaining access to oil reserves previously too expensive to develop is all made possible with steam. Steam Assisted Gravity Drainage or (SAGD) is one process to extract oil from large “oil sands” reserves.
The oil sands, also known as the tar sands, are largely located in remote areas of Canada and Venezuela. With approximately 450 billion barrels of oil between the two countries, those reserves match the approximate size of the oil reserves in Saudi Arbia. Oil sands are either loose sands or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and water, saturated with a dense and extremely viscous form of petroleum technically referred to as bitumen.
Previously this bitumen was mined by primarily traditional surface mining extraction methods which leaves an indelible mark on the land. SAGD allows access to the bitumen using a far less invasive strategy.
How does SAGD work?
It’s actually very simple. Two parallel wells are dug, tapering into two parallel horizontal wells. The top well is known as the steam injection well. The bottom well is known as the production well.
After the wells are dug, steam is forced into the injection well. The steam heats the surrounding bitumen which loosens/liquefies the mixture making it less viscous and free flowing. Gravity allows the mixture to seep into the bottom production well. Pumping equipment is then used to take the bitumen to the surface where the water and oil are separated and go through a “clean up” process that readies the oil for commercial use.
SAGD is not the only way you can access the oil in the oil sands using steam. There is also a method called Steam Enhanced Extraction, or (SEE) for short. SEE is also known as steam flooding – aptly named, steam flooding is a process by which steam is pumped into the ground and forces steam horizontally. As the steam cools it turns back into water (hence “flooding”) and forces its way into a nearby production well. This method is not only used to extract bitumen, but is used to remove contaminates from the ground.
At the heart of these enhanced oil recovery methods is steam. Having a resource that can properly select a steam boiler for these applications is critical to the operation’s success. For more information about industrial steam boilers for SAGD and SEE applications, contact WARE today (502) 968-2211.