Relatively new bitumen recovery processes, such as SAGD, minimize the environmental footprint in terms of land disturbance and water demands. However, as a corollary, air monitoring becomes more difficult. In particular, monitoring for sulphur and nitrogen oxides, as currently practiced, suffers from significant limitations in remote regions, such as the Canadian oil sands areas. Current techniques require the placement of monitoring trailers in accessible locations, but the electrical power or even access for optimal location for trailers is not always given. In addition, the trailers are capable of monitoring air quality only at the location of their deployment.
There would be an advantage in deploying monitoring techniques that require minimal power (e.g. car battery, solar cell) and are capable of measuring air quality at a distance from the place of deployment.
In the autumn of 2008, a trial of DOAS (Differential Optical Absorption Spectroscopy) was undertaken in northern Alberta and northern Saskatchewan, at four SAGD plants in various stages of development. Results of this study, and a discussion of the technology, will be given. Advantages and limitations of DOAS for deployment in Athabasca will be discussed. In general it was found that SO2 results showed remarkably low degrees of contamination, while NO2 concentrations were more noticeable.
Conventional techniques for air quality monitoring in Western Canada have, for several decades, relied on monitoring trailers deployed in strategic locations downwind from major emitters. Typically, sulphur dioxide, for example, is measured by pulsed fluorescence spectroscopic techniques. These systems have proven to be quite reliable in the past.
The northern Canadian heavy oil and oil sands areas, however, present unusual challenges that limit the applicability of the conventional techniques. Most projects are located in the boreal forest areas of the Canadian west, and it is therefore necessary to minimize the environmental footprint of such projects. The more recently developed in-situ recovery techniques, primarily Steam Assisted Gravity Drainage (SAGD) are in fact capable of significantly reduced footprints by virtue of their reliance on horizontal well technology. Horizontal sections of such wells are now of the order of 800 meters, and multiple wells can be drilled from a single location.
It is this reduction in land disturbance that, as a corollary, makes extensive air quality monitoring more difficult, for the following reasons:
Monitoring stations of the conventional type require building of access roads or clearings.
Electrical power lines need to be installed to the trailer sites chosen, because permanent mains power is required for trailer operation.
Any trailer so deployed is capable of measuring air quality only at the point of deployment; air quality assessment at a distance is not possible.
Given that the oil sands area in northern Alberta alone is of the order of 140,000 square kilometers in area (and is therefore larger than most European countries and just under half the size of Germany or France) adequate monitoring of air quality in the region may well become part of the footprint problem if the current technology is not at least augmented by other techniques.
