In North America Exploration and Production we have water recycling and brackish water programs in place. At Primrose and Wolf Lake (PAW) we recycle more than 98% of the produced water. Our ongoing reduction of fresh water use is being accomplished through a long term brackish (saline) water source development plan, including associated brackish wells, field and plant infrastructure. Efforts to improve fresh water use efficiency at PAW have resulted in 40% decrease of fresh water use per barrel of bitumen production since 2007. See graph below on PAW water use.
Primrose and Wolf Lake operations water use
We also treat and use brackish water at our Brintnell project in the Pelican Lake area, where we have pioneered polymer flooding for Enhanced Oil Recovery (EOR). In 2011, we completed substantial improvements to recycled water handling. As a result of this work, the recycle rate is currently 90% and we expect to maintain this rate for polymer production through 2012. All future polymer flood development is being designed and planned for saline water usage. Alternate sources of saline water supply are currently being evaluated.
We do not use any fresh water for water flooding in our SE Saskatchewan and Manitoba operations.
Our Nipisi fresh water usage in 2011 increased from 2010 due to the repair of several injection wells, which significantly increased the injection capacity of the field. Nipisi continue to have very high produced water recycle rates with 99.9% during 2011.
Our Horizon Oil Sands operation is designed to recycle over 80% of the water used in bitumen extraction so that it can be reused in our processes. Water withdrawals from the Athabasca River continue to be far less than our authorized withdrawal limit. We also keep water supply storage onsite that allows us to maintain production in the event of low water flow periods in the Athabasca River, during with withdrawals from the river may be restricted. Our Horizon water management system is a closed loop and does not release water offsite. Learn more about our innovative ways to reduce fresh water use and how we are recycling water at our Horizon plant.
Canadian Natural's Septimus unconventional natural gas project in northeast British Columbia is also designed to conserve fresh water. We source brackish water from deep wells from hydraulic fracturing. Also, the produced water is further treated and reused to frac subsequent wells.