Canada’s oil sands have been valued for millennia—18th century explorer Sir Alexander Mackenzie passed through the area and reported locals using bitumen and spruce gum to seal their canoes. Ever since first commercialization in the 1960s, processes have become cleaner and more efficient most notably in recent years.
It has come a long way. In 1978 it took ten barrels of fresh water to produce a barrel of bitumen. Today, the world’s second-largest producer, “Suncor Energy” can boast a water-oil ratio of 0.17.
Reducing fresh water usage and dealing with tailings ponds has been one of the industry’s biggest challenges and that’s where most breakthroughs are focused. Case in point: a revolutionary new process called TRO—Tailings Reduction Operations—being introduced by Suncor will soon enable recycling water from tailings ponds much quicker. “We expect to generate surplus water as our existing tailings ponds are reclaimed far quicker than before,” said Gord Lambert, Suncor’s Vice President, in an online interview. With TRO, fine tailings are mixed with polymer flocculent, which when dried can then be reclaimed in place or relocated.
Drying can be done in a number of weeks, so reclamation and recycling are accelerated. It’s almost an embarrassment of riches—the company will have more water than it needs at which time it will send to other operators, reducing overall industry demand. Lambert reckons sending it to other operators would certainly be revolutionary, “because it means getting past individual corporate bragging rights in favor of doing what’s best for the regional watershed.”
When it comes to their in situ operations, Suncor again created a new approach to water efficiency. Not having the traditional disposal wells handy, they devised a system called Zero Liquids Discharge (ZLD). ZLD removes the salts and recycles the water to produce more injection steam leaving only the salty solids for disposition. Consequently by 2009, 97.5% of the injection steam needed for their MacKay River SAGD operation was continuously being recycled.
When Devon Canada’s Jackfish operations began production in 2007, the company became the first oil sands operator to use 100% saline water to create steam for its SAGD operations. High initial costs—finding the aquifer,drilling, testing, and special saltwater-friendly boilers— were reclaimed. Now over 95% of it is recycled back into the steaming operation. Devon plans to use the same method for Jackfish 2 starting in 2011.
Another innovation promises to revolutionize froth as it enters tailings ponds. Edmonton-based Titanium Corp. has developed a hydrocarbon and water recovery plant that will recover bitumen and heavy minerals concentrate. The concentrate goes through a mineral separation plant to extract valuable ilmenite, leucoxene and zircon. Water is reused and dry tailings leftovers go to reclamation. On-site commercialization is planned for 2011.
Canadian Natural Resources Limited is instituting a new idea for its tailings ponds too, at its Horizon Oil Sands facility. Waste CO2 is injected into the tailings slurry lines before they enter the pond, where it reacts to form carbonic acid. This changes the pH of the tailings mixtures to allow fine clays, silts and sand to settle out more quickly, ensuring prompt water recycling. To further improve efficiency, during their next phase, there’s another new treatment: cyclones will remove water from the coarse sand, and thickeners will remove water from the fine clays, silts and sand. The de-watered streams will then be combined with waste CO2. Tailings will be depositedin the disposal area where even more water will be released and reused. Overall, it reduces tailings pond footprints and reduces the need for river water, plus the elimination of 219,000 tonnes of CO2 emissions per year.
Even with these breakthrough techniques, tailings ponds still need reclaiming. This may take decades. Standard reclamation programs have started to plant a mix of grass seeds and to let trees grow naturally. Last year ConocoPhillips took heed of research programs made by the University of Alberta, and planted three tree species: spruce, birch and aspen. Next they plan to nurture native shrubs, indigenous flowers and even wild blueberries.
Reclaiming wetlands has presented a number of problems. Wetlands in the Cold Lake oil sands operations area are mainly bogs, fens and water- saturated peat. The challenge is in replacing the complex suite of waterfowl, wildlife and fish species. Two years ago, Imperial Oil and Ducks Unlimited Canada teamed up on a pilot project with a new idea. A clay cap and geotextile liner were laid over the wetland to protect its seeds before the well pad was built, to maintain drainage across the site and allow natural vegetation and wildlife habitat to return afterwards. So far, it has worked—when the liner was removed after winter, natural vegetation re-sprouted.
An efficient way of producing oil sands virtually without the need for water or natural gas—and thus lower capital and operating costs—has been Petrobank’s THAI (Toe to Heel Air Injection), now poised for large-scale commercialization. THAI combines controlled combustion with vertical and horizontal wells. The principle is basically an underground combustion front forced along by air injection. The heat reduces the bitumen viscosity and the crude is collected by horizontal production wells below. Massive greenhouse gas reductions and underground upgrading using catalysts are bonuses.
Bitumen upgrading is another phase companies are making more efficient and environmentally sounder. North West Upgrading for example will upgrade and refine bitumen into diesel fuel and other products in a single location by adding hydrogen during the on-site process. The hydrogen is obtained by burning the heavy bottom of the bitumen barrel with pure oxygen. The large volumes of pure CO2 produced are used in EOR (enhanced oil recovery) and in that process stay sequestered underground.
Capturing CO2 is also a bonus with Nexen and OPTI Canada’s conversion of heavy oil waste into synthetic gas to help fuel their Long Lake SAGD operations. The gas is produced from asphaltene bitumen residue and used to run both the SAGD and the upgrading operations, significantly reducing the amount of natural gas that’s required. The companies claim producing a barrel of sweet synthetic crude ten dollars cheaper than other operators. Also, the bitumen is upgraded to premium synthetic crude on site using a proprietary technology, a gasifier and a hydro cracker.
Cenovus Energy has piloted a new process to aid efficiencies with their SAGD operations: SAP—Solvent Aided Process, which adds butane to injected steam. Now in its third test at the company’s Christina Lake operations, it has reduced water usage by 10%, dropping its steam/oil ratio from 2.2 to 1.9. Further gains are expected as the pilots progress.
When it comes to oil sands mining operations, extraction solutions are still being discovered, currently with the use of solvents to separate out bitumen. Researchers at the Imperial Oil-Alberta Ingenuity Centre for Oil Sands Innovation (COSI) at the University of Alberta for example are exploring that. It’s cutting edge research with the eventual goal of totally eliminating the need for water in extraction operations: essentially dry-cleaning it. Hurdles remaining include: how to recover the solvents from tailings?
Those original historical bitumen users haven’t been forgotten either. When developing their Horizon Oil Sands project, Canadian Natural Resources scored an industry first in compensating local First Nations communities for the unavoidable disruptions to their watersheds. After years of consultation, the company built an entire lake ecosystem to duplicate the natural one—complete with native plant and fish species.
Did you enjoy this article?
We respect your privacy and will never share your information with third parties.