EXAMPLES OF THERMAL CAPROCK OR CASING FAILURE PROBLEMS IN ALBERTA


Imperial Oil, Cold Lake (1988-2015)

Background


Imperial Oil's thermal operation in Cold Lake has been plagued by caprock breach and casing failure problems since its beginning. One of the early reported incidents dates back to 1988 when over 6,000 barrels of bitumen emulsion spilled into the boreal forest and contaminated three shallow aquifers. Over 2,600 cubic meters of contaminated soil, water and bitumen had to be transported to a landfill in the wake of the incident.   

The caprock and casing failure problems in Imperial's HP CSS operation in Cold Lake continues to date. Based on Imperial's annual progress presentations to AER, numerous oil-in-shale anomalies are being discovered all over the Imperial pads, and from depths ranging from reservoir to near-surface aquifers. On F-Trunk Pad, for instance, a group of oil-in-shale observations were discovered in 2001 that spanned over one kilometer wide. An investigation was completed by Imperial  in 2003 but was not successful in identifying the cause of oil migration to those near-surface locations

Imperial Oil also reports major fluid excursion from reservoir into Grand Rapids at various pads and different cycles.  The annual
presentations also indicate 65% of wells have experienced failure in their lifetime with near surface failures having made direct adverse environmental effects. 

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Total E&P, Joslyn (2006)
Background

On May 18, 2006, a major blowout occurred at Total's Joslyn SAGD project. The incident near the heel of a SAGD pair created a huge 125m x 75m crater with rock debris flying up to 300m away.  On the aftermath of the incident, that was decribed as "catastrophic" by the regulator, Total abandoned its Joslyn SAGD project. 

Total E&P completed a detail investigation report in 2007. And the regulator (ERCB) reviewed and issued their own investigation report in 2010. Another report was released by a joint review panel from the Federal Minister of Environment in 2011. The conclusions on the cause of the incident differ from one another and none conclusively identified the cause of the failure.

Caprock failure in Joslyn, although not as frequent and extensive as Cold Lake incidents, has been very significant by impacting how SAGD projects are being regulated in the province. Joslyn incident was dealt with more transparently compared to other incidents, and such, it raised awareness about the risk of caprock failure for in situ thermal recovery. In the wake of this incident, a joint caprock integrity study was initiated involving Alberta Geological Survey, Directive 051 was undergone a revision, and a new directive for shallow SAGD operation is drafted requiring detail caprock integrity study for the SAGD development applications.   

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CNRL, Primrose (2009-2015)
Background

CNRL's Cyclic Steam Stimulation operation in Primrose has been a scene of major caprock and casing failure incidents in the past few years. The first reported incident was a surface release of bitumen emulsion discovered in January 2009. The leaks observed near two surface fissures resulted in removal of over 1,000 cubic meters of bitumen emulsion as well as 12,000 tonnes of contaminated material from the site. Later that same year CNRL reported observed temperature anomaly in Grand Rapids formations as well as casing failures in other parts of its Primrose operation. The seepage event contaminated the Bonnyville Aquifer.

The leak through the fissures continued but an investigation completed by CNRL in 2010 did not find the definitive cause of the incident. Later that year CNRL received approval for dynamic steam injection as well as expansion of their HP CSS operation to a new area in East Primrose. Early 2013, CNRL reported the discovery of four new oil spills that were spread all across their operation from East to South Primrose, resulting in more than 1.2 million liters of bitumen release to surface, and affecting a massive area of boreal forest. One of the leaks that was located below a water body, resulted in unprecedented action of draining a small lake for cleanup. Based on annual presentations to AER, CNRL also reports numerous casing failures every year including one in January 2014 that released 27,000 liters of bitumen into overburden. 
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