The Alberta Energy Regulator (AER) said on July 22 that it agrees with the assessment that the steaming strategy and wellbore issues were the main contributing factors to last year’s bitumen flow-to-surface (FTS) incidents at the east and south sections the Primrose project operated by Canadian Natural Resources Ltd. (CNRL).
The response comes after AER completed a preliminary review of both the CNRL causation report, received on June 27, and the independent technical review of CNRL’s report.
The technical review indicated that CNRL’s strategy to inject large volumes of steam at fracture pressure in closely spaced wells was a fundamental cause of the FTS incidents.
Four FTS incidents have been reported to AER since May 2013, resulting in the recovery of 1180 cu m of bitumen emulsion from the sites in an affected area covering 20.7 hectares (OGJ Online, July 18, 2013).
“Our assessment of the reports leads us to believe that these [FTS] events can be prevented if proper mitigation measures are put in place,” said Jim Ellis, AER president and chief executive officer.
Restrictions on steaming activity at Primrose East and within 1 km of Primrose South have been in place since June 2013. AER says the bitumen release has been contained, with cleanup efforts ongoing.
Ellis said AER, however, is “not prepared to approve a return to full operations at these sites until all potential risks are addressed and proper requirements are in place to avoid a similar incident,” adding, “This will require a gradual, step-by-step approach that allows us to manage those risks.”
AER’s investigation is ongoing, and it continues to examine what measures can be put in place to prevent similar incidents. CNRL and the panel that conducted the independent technical review continue to collect and analyze data and will submit final reports to the AER in September once all the data have been analyzed.