Exceedances

Unique Technology, Unique Challenges

Nexen incorporated a unique combination of technologies in the design of our Long Lake in-situ oil sands facility. Long Lake is the first oil sands project in Canada to combine Steam Assisted Gravity Drainage (SAGD) technology with an upgrader that employs gasification technology. By pioneering gasification, we take a portion of the bitumen barrel (asphaltenes) largely unused by most other industry players and convert it into syngas to help fuel our operations.

Utilizing syngas reduces our exposure to fluctuating natural gas pricing, and more importantly, it also allows us to get the most energy from every barrel of bitumen. However, as with the start-up of any complex industrial facility, we did experience some challenges including an unacceptably high number of air exceedances – particularly of nitrogen oxide (NO_x) – which are monitored as part of our regulatory licence to operate. These exceedances are associated with unplanned equipment shut downs.

Although zero exceedances is our ultimate objective, we targeted at least a 50% reduction in exceedances at Long Lake in 2011 and we've already seen significant improvement in the first seven months of the year. Specifically, we reduced exceedances in Long Lake’s Heat Recovery System Generators (HRSG), Once Through Steam Generators (OTSG) and Sulphur Recovery Units (SRU) as a result of increased reliability, more operator education and revised procedures.

Exceedances in the utility boilers remains unacceptably high. Though this equipment met manufacturing and regulatory specifications when it was installed, performance has since declined. We’re working with the manufacturer to determine the root cause of this problem. In addition, we’re proactively involving Alberta Environment as we work to improve performance in this area.