Steam-Assisted Gravity Drainage (SAGD)
Steam-assisted gravity drainage (SAGD) is a thermal enhanced oil recovery method that involves drilling two parallel horizontal wells, one approximately five metres above the other. Steam is continuously injected through the upper wellbore, softening the bitumen, which then drains into the lower wellbore and is pumped to the surface. These pairs of parallel horizontal wells, one for steam injection and one for production, make it possible to recover bitumen continuously from an oilsands formation.
The SAGD process is an Alberta success story. It was introduced by Dr. Roger Butler in 1978. In 1984, the Underground Test Facility was initiated as an in situ SAGD bitumen recovery facility. Owned and operated by 10 industrial partners and with government funding, the facility allowed for research that confirmed the SAGD process and its commercial viability.
Since the late 1990s, SAGD has begun to see widespread commercial application.