CNRL Primrose FAQs

September 15, 2014

Incident History

Question: When did these incidents occur?
Answer: The first flow to surface incident was identified in May 2013. Between May and June 2013, CNRL reported four flow to surface incidents at the Primrose East and South locations.

Question: What did the AER do when the incidents were discovered?
Answer: The AER immediately responded with inspectors and investigators to ensure the FTS incidents were being appropriately managed. As per our protocol, once the releases were contained and clean up was underway, we moved to a full investigation into the incidents. Restrictions were put into place at Primrose East and South while the investigation takes place.

Question: What restrictions were put in place?
Answer: In July 2013, the AER prohibited steaming at all of Primrose East and within one kilometre of the Primrose South FTS location. This restriction has been amended to allow low-pressure steaming in Primrose East.


Causation Report

Question: What caused the incident?
Answer: The CNRL report indicates that there are four enabling factors that could have caused the FTS incidents. The four factors include:

  • Excessive release of bitumen emulsion from the producing reservoir into the overlying Grand Rapids
  • A vertically induced fracture that moves to the top of the Grand Rapids formation
  • A significant heaving of the overburden (overlying shales) which could allow for vertical fractures.
  • In addition, there are vertical pathways through which fluid can travel through shales (i.e., existing wellbores and/or natural fractures or faults), which may have contributed to the FTS events.

Question: So are you just taking their word for it?
Answer: The causation report was completed by CNRL staff, however the AER has been collecting and analysing data (both that collected by CNRL and its own information) and conducting a technical review as part of our investigation. In addition, the AER ordered a third-party review by an independent panel of technical experts.

Question: Who is on the independent panel?
Answer: The panel includes experts in the field such as Russ Bacon, P.Eng., Keith Hirsche, Rick Kry and Pat McLellan, P.Eng. The panel was selected by CNRL in response to an Environmental Protection Order (EPO) issued by Alberta Environment and Sustainable Resource Development. The responsibility for the EPO was transferred to the AER on March 29, 2014.

Question: What does the independent panel say caused the incidents?
Answer: While the independent panel agreed with the factors pointed out by CNRL, they indicated that the steaming strategy that CNRL employs, namely large volumes of steam injected at fracture pressure in closely spaced wells, is a fundamental cause of the FTS events.

Question: Does AER agree with the cause of the incident?
Answer: The AER agrees with the conclusions of the July Causation reports in that the FTS incidents were likely caused by a combination of CNRL’s particular steaming strategy and potential well bore issues. As a result, the AER is not prepared to allow full high pressure operations at these sites until all potential risks are addressed and proper requirements are in place to avoid a similar incident. This will require a gradual, step-by-step approach that allows us to manage those risks.


Application Approval

Question: What has the AER approved?
Answer: The AER has approved CNRL’s application to convert operations at Primrose East from high-pressure to low pressure steam, less than half of original steam pressures. The AER is satisfied this approach will successfully mitigate potential risks of further bitumen release at the sites.

Question: Why did the AER approve CNRL’s application?
Answer: The AER is satisfied that the modified low-pressure approach to steaming operations effectively address all four factors identified in CNRL’s Causation Report that enable an FTS release to occur. The independent panel also agreed with CNRL’s identification of the four contributing factors and stated that three of them would be mitigated by a low pressure steaming operation similar to the one proposed in CNRL’s application.

CNRL will use much lower steam pressures – from 11 MPa to 4 MPa. MPA stands for megapascal. The pascal (symbol: Pa) is a unit of pressure defined as one newton per square metre.

Question: Why would the AER allow steaming to resume before the investigation is complete?
Answer: Although the investigation continues and CNRL’s final report has not been submitted, no further information is expected to be provided in the final report that will influence the technical recommendation. The AER is satisfied that the causation reports submitted in July have identified the causes of the FTS event, allowing the investigation to move into its final phase. Allowing low pressure steaming will also allow the AER to assess the modified approach and ensure all appropriate measures have been taken to prevent another flow to surface event..

Question: What happens if the flows from the FTS sites increase or new FTS incidents occur?
Answer: If flow rates at the existing sites increase, or new sites occur, the AER will immediately take action to address the event and may require the company to stop steaming.

Question: Will you be monitoring the effects of the low-pressure steaming?
Answer: Last summer the AER directed CNRL to enhance monitoring at the Primrose sites. That monitoring remains in place and will assess any impacts to low pressure steaming.


Future Operations at CNRL

Question: Why doesn’t the AER just shut CNRL down completely until the investigation is completed?
Answer: The restrictions put in place are designed to address those areas where FTS incidents have occurred. CNRL has conducted operations on a modified basis, with reduced volumes as directed by the AER, without FTS incidents at other sites. The AER does not feel a full shut down of operations is warranted at this time.


Investigation Status

Question: When will the AER investigation be complete?
Answer: The AER expects CNRL and the independent panel will complete their reports by March 2015. Shortly after, the reports will be made public.