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By Jeff Danner Jeff has worked in both the chemical and biotech industries and is the veteran of thousands of science debates at cocktail parties and holiday dinners across the nation. In his Common Science blog, Jeff aims to make technological and scientific concepts accessible to all.

Something is Rotten in the Province of Alberta

By Jeff Danner Posted August 5, 2013 at 5:14 am

2986100971_e1faba0513_zScheduling conflicts this week have prevented me from putting together a full analysis of the topic for this week’s column. I will provide more details in the future, but for the time being, I wanted to apprise you of some troubling events in the Alberta Oil Sands.

The oil sands in Alberta are pretty much what they sound like, oil mixed with sand and a variety of other impurities, many of which are both difficult to remove and toxic. Compared to a traditional oil field, the hydrocarbons in Alberta, referred to as bitumen, are larger and have longer molecular chains, which cause the bitumen to exist as a solid rather than a liquid at ambient temperatures. In order for bitumen to become liquid enough to flow through pumps and pipelines it must be subjected to some combination of heating, dilution with lower molecular weight hydrocarbons, and/or chemical processing, to break the large molecules into smaller ones. When dilution, the most common approach, is used, the resulting material is called “dilbit” for diluted bitumen.

Bitumen is extracted from the ground in two ways. The material nearest to the surface is strip mined. In this technique, the earth, sand, and bitumen is excavated, put into the largest dump trucks ever built by mankind, and moved to a processing facility. About 20% of Alberta’s oil sands can be excavated by strip mining.

The other 80% of the bitumen is buried too deeply to be strip mined, so the oil companies plan to recover this material by injecting high-pressure steam several hundred feet into the ground to melt the bitumen and then allow it to flow back up to the surface through the same pipes used for the steam injection. This type of processing has been given a number of different Orwellian-sounding names. I’ll call it in-situ processing for the remainder of this column. In-situ processing has been demonstrated to be feasible on the small scale. Now that much of the shallow bitumen has been excavated via strip mining, oil companies are beginning to attempt in-situ processing on a large scale.

The scale-up of in-situ processing, to be diplomatic, is not off to a good start. The near surface zones where in-situ processing is practices contains relatively soft and porous geologic formations. When melted and pressured in this environment, the bitumen is not demonstrating any particular compunction to restrict its movement to within the pipes, as intended by the oil companies. It is flowing to the surface through cracks and porous materials and seeping into adjacent underground aquifers.

An uncontrolled excursion such as what I described above has been ongoing in Cold Lake, Alberta since late May. Once the bitumen has been heated and pressurized, there is little that can be done to mitigate the situation. The full environmental impact will not be known for some time. My instincts tell me that this type of event will become quite common if in-situ processing is applied on a large scale.

I have decided that from now on, any time I write a column on fossil fuels or climate change, that I will close by reminding you of the most important part of the story. Humans have already raised the carbon dioxide concentration in the atmosphere to 400 parts per million (ppm), a level 33% higher than it has been during the last half a billion years. At 400 ppm we are already experiencing changes in our climate which threaten our well being. Climate scientists predict that an atmospheric carbon dioxide concentration of 450 ppm represents a tipping point for the climate, at which point serious damage will occur to human civilization. Remaining below 450 ppm will require that we leave over half all currently-know fossil fuel reserves in the ground, forever. There is likely no better candidate to be left in the ground that the bitumen deposits in Alberta, yet we continue to scratch and claw them from the earth, even it if means turning Northern Alberta into a toxic wasteland.

Have a comment or question? Use the interface below or send me an email to commonscience@chapelboro.com.

image by pembina.institute

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