Water use in the oil sands is under increasing scrutiny by the public and regulators, making it a key issue for oil sands producers. Some of the concerns related to water use by steam-assisted gravity drainage producers include:
Water used for the production of bitumen in ConocoPhillips Canada’s Surmont Phase 1 steam-assisted gravity drainage operations is groundwater drawn from the Lower Grand Rapids formation, more than 150 metres below the surface. It contains water with 1,200 to 2,500 milligrams per litre of total dissolved solids per litre and a number of naturally occurring elements that make the water unfit for human consumption, agricultural or livestock purposes without extensive treatment. Water we use during bitumen production does not include surface water such as river water, lake water or water from shallow groundwater sources that are currently being used, or may be used, by municipalities, local landowners or agricultural operations.
We also use water to build ice roads in winter, for dust control in summer, to drill new water wells, to drill wells to increase our knowledge of the thickness and distribution or our bitumen reserves, and to drill wells to produce bitumen. For these purposes we use local surface water, for which licenses are obtained from Alberta Environment and Resource Development, as well as reused, treated water from our Surmont staff housing facility.
In steam-assisted gravity drainage operations, source water is drawn from reservoirs located at depths greater than 150 metres below the surface, treated and used to generate steam. The steam is injected into the ground and most of the water is delivered back to the surface with the oil. This produced water is recycled and treated for reuse in steam generation to improve efficiency.
A small amount of water is consumed during the process and is replaced with makeup water to balance the cycle. One of the ways a small amount of water is consumed is through boiler blowdown, which is one of the byproducts of steam generation. Boiler blowdown is a waste fluid made up of water and a high concentration of dissolved and suspended solids. A portion of the boiler blowdown water is recycled and the remainder is treated and sent to a licensed disposal well, where it is disposed by deep well injection more than 300 metres below the surface. This complies with the strict Energy Resources Conservation Board regulations.
In Alberta, water use for steam-assisted gravity drainage operations is regulated by Alberta Environment and Sustainable Resource Development and the Energy Resources Conservation Board. Key regulations that provide regulatory guidance on water use have been revised in 2006, 2009 and 2012, with more revisions anticipated in 2013.