In SAGD operations, pairs of stacked horizontal wells are drilled into the reservoir about 400 metres beneath the surface. The top well injects steam to heat the bitumen, which separates from the sand and collects with the produced water in the lower well, approximately five metres below. The bitumen is then pumped to the surface, where it is separated from the water. The water is treated and recycled into the system.
The steam-oil ratio, or SOR, is an indicator of the efficiency of a SAGD operation. Generally, an SOR of less than 3 is considered to be an efficient operation. At MEG’s Christina Lake project, SOR has typically been 2.5 or less. Lower rates equate to greater cost efficiency, as less steam-generating infrastructure is required. Low rates also mean greater energy efficiency, as less natural gas is used in the process.
MEG typically recycles more than 90% of the water used to produce steam. Additional requirements are found from deep water sources that are not suitable for consumption or agricultural uses. No surface water is used in the process.
- Access to resources. More than 80% of Canada’s oil sands can only be accessed by drilling technologies, like SAGD.
- Reduced environmental footprint. With horizontal wells stretching more than a kilometre beneath the surface, a large area can be developed with minimal impact to the land. SAGD operations typically disturb only 10% to 15% of the surface of the development area.
- Manageable growth. SAGD allows development in stages, helping to manage costs and workforce peaks. MEG’s current operations and future plans are based on multi-stage expansions of between approximately 25,000 and 50,000 barrels per day.
- Technology upside. While SAGD is a proven technology, it is still relatively young and holds the potential for improved recovery rates, greater energy efficiency and lower costs as we continue to research and test potential enhancements.