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New solvent-based process could dramatically reduce the cost and environmental impact of recovering oil from tar sands

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A new Canadian technology shows promise as an environmentally-friendly way to extract oil from Alberta's tar sands by using significantly less energy than conventional steam-extraction methods.
Dubbed N-Solv, the technology, which involves the injection of propane into the tar sands in place of steam, will soon be put through the paces in a demonstration project led by Mississauga, Ontario-based engineering firm Hatch Ltd. and Calgary-based consulting firm Nenniger Engineering Inc. The project will be funded in part by Sustainable Development Technology Canada (SDTC).

While solvent injection is not new, Hatch and the N-Solv team are taking a fresh look at ways to overcome hurdles that previously made it uneconomic. If the N-Solv solution works as planned, the technology could have a significant impact on oil recovery from Alberta's oil sands, which constitute the majority of Canada's petroleum reserves – the second largest in the world after Saudi Arabia.

N-Solv has overcome the first hurdle in getting its process to market – attracting the necessary funds to further develop and demonstrate the technology on the path to commercialization. In this case, Hatch and Nenniger Engineering turned to SDTC, a foundation created by the Government of Canada to support the development and demonstration of clean technologies. The SDTC funding, as well as additional funding leveraged through project partners, will be used to build and operate a 2,000-barrels-of-oil-per-day demonstration plant in Alberta. SDTC's funding is subject to final contract negotiations. “SDTC helps to de-risk clean technologies like N-Solv, thereby assisting its progress to market,” says Rick Whittaker, Vice President, Investments, with Ottawa-based SDTC.

Background

There are two main techniques for recovering bitumen from the tar sands: mining and drilling. If the bitumen is close to the surface, mining is the most practical option. The bitumen is easily, though expensively, processed to recover oil and a variety of other gases.

However, since 90 percent of bitumen is located many hundreds of metres below the surface, drilling is the only alternative to extract the majority of the reserves. Traditionally this method involves the injection of steam, which helps liquefy the bitumen, making it possible to pump it to the surface. The process requires large volumes of steam, which is produced by burning fossil fuel, resulting in significant greenhouse gas emissions and air pollution. A second downside, and one of particular concern in relatively arid Alberta, is that the process uses large amounts of water. Adding to the environmental impact, the water has to be de-mineralized to avoid clogging the steam production machinery, with the resultant brine buried deep underground.

“Our challenge is to get the N-Solv process tested in a field pilot as soon as possible so that we can prove to the investment community that there are better choices available than steam,” John Nenniger says. “The environmental benefits could be significant and if our field demonstration shows that the environmentally friendly path is also the most profitable choice, then the markets can respond quickly and force a change in direction.” Photo courtesy: Suncor Energy Inc.

The N-Solv machinery pumps propane gas into the tar sands – heated to approximately 60ºC. When the propane interacts with the sands underground –where the temperature is six to 13ºC year-round – it condenses, and the bitumen dissolves into the liquefying propane. By operating at slightly elevated temperatures, the propane actually warms the bitumen, thus accelerating the extraction rate. Laboratory tests indicate commercially viable extraction rates are achieved using 80 to 90 percent less energy than steam, says Stephan Broek, Hatch's director of technology commercialization, in Calgary.

The mixture of bitumen and propane then drains through the sand to a second set of pipes. The resulting fluid mixture can then be pumped to the surface for further processing, including the recovery of the propane for re-use.

The idea of injecting unheated solvent vapour into the tar sands and using gravity drainage to extract the bitumen was originally patented in 1976 by a senior VP for Hatch, Emil Nenniger. This process was studied at the Alberta Research Council, the University of Alberta and the Ontario Research Foundation during the 1970s and 1980s. The research showed that solvents had a remarkable ability to liquefy bitumen, but that the extraction rates were too slow to be commercially viable.

In the late 1990s, John Nenniger (Emil's son) theorized that the extraction rate would be greatly accelerated if the propane was heated. The father and son team approached Hatch to partner in the technology development. In 2004, an experimental test program was conducted that confirmed Nenniger's theory while also showing an additional benefit –propane upgrades the quality of the bitumen extracted from the tar sands by leaving some of the unwanted byproducts, such as asphaltenes, behind in the reservoir. “Our challenge is to get the N-Solv process tested in a field pilot as soon as possible so that we can prove to the investment community that there are better choices available than steam,” John Nenniger says. “The environmental benefits could be significant and if our field demonstration shows that the environmentally friendly path is also the most profitable choice, then the markets can respond quickly and force a change in direction.”

“The technology could lead to a large reduction in natural gas consumption compared to steam technology, thus eliminating huge amounts of greenhouse gas emissions,” Whittaker says.
Nenniger says the reduction could eventually be equivalent to the GHG emissions from all Canadian automobiles.

The N-Solv demonstration plant, to be located in the Fort McMurray, Alberta area, is scheduled to go online in 2007.

With an investment fund of $550 million, SDTC supports clean technology projects through the critical stages between research and commercialization. In doing so, SDTC helps increase the chances that Canadian innovations like N-Solv succeed in an increasingly competitive global marketplace. To date, SDTC has invested $169 million in 75 projects, almost one-quarter of that in the energy exploration and production sector. This investment is leveraged almost three times through funding from consortia partners, which have provided another $446 million.

Research work to develop N-Solv was funded in part by the federal government's CANMET Energy Technology Centre in Ottawa, under the Industrial Energy Research and Development program of Natural Resources Canada.

About the author: Vicky J. Sharpe is President and CEO of SDTC. For more information on SDTC, please visit www.sdtc.ca.

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