Steam Assisted Gravity Drainage (SAGD)
What is SAGD?
Steam-assisted gravity drainage (SAGD) is a specific form of heavy oil extraction. Nearly all heavy oil and oil sands are too viscous or thick at ambient reservoir temperature to flow on its own. SAGD recovery involves drilling pairs of horizontal wells, one placed above the other in each pair. Steam is injected into the upper horizontal well. The steam heats the reservoir, thinning the heavy oil and oil sands which can then drain through gravity to the lower horizontal well. The oil sands-water mixture is then pumped to the surface.