News Release 2011-08-16

 

News Release 2011-08-16

News Release 2011-08-16 (NR2011-20)

VIEW PDF (69.38 KB)

ERCB issues conditional approval for the resumption of pipeline operations to Plains Midstream Canada

For immediate release

Calgary, Alberta (Aug 16, 2011)… Following a comprehensive review and assessment, and a third-party engineering review of the incident (see attached Background), the Energy Resources Conservation Board (ERCB) has provided conditional approval to Plains Midstream Canada (Plains) to resume operations of the NPS 20 Rainbow Pipeline following the failure on April 28, 2011.

Plains is responsible for ensuring that the pipeline can be safely operated within all regulatory requirements. Prior to resuming operations, Plains must confirm it has met the following conditions:

  • Completion of work, to readiness for backfill, of all excavated sites inspected as per ERCB’s direction of May 17, 2011 (five priority sites and five additional sites);
  • Implementation of weekly aerial surveillance of the pipeline to monitor for geotechnical hazards;
  • Improved procedures and operations to ensure effective response should another failure occur; and
  • Implementation of a Community Consultation Plan submitted to the ERCB on May 12, 2011, which includes meetings with local stakeholders prior to resumption of operations.

The ERCB requires Plains to submit monthly progress reports and attend monthly meetings with ERCB personnel to ensure effective implementation of conditions of approval and regulatory requirements.

The ERCB also directed Plains that the interim maximum operating pressure of the pipeline will be limited. Operating pressure will be determined subject to ERCB review of pressure values within 30 days of the time of the failure.

The engineering assessments concluded that the April 28, 2011 failure was due to high- stress on an existing crack in a fillet weld that was made on a weld-on sleeve. Plains has committed to excavating and inspecting all sections of the pipeline containing these types of weld-on sleeves on an expedited schedule.

The ERCB continues its official investigation into the incident and will issue a full report at a later date.

A start-up date has not been confirmed.

– 30 –

For more information, please contact:

Kim Blanchette, ERCB Communications
Phone: 403-619-9455
E-mail: Kim.Blanchette@ercb.ca
Media line: 1-855-474-6356

NR2011-20

BACKGROUND – ERCB Assessment of NPS 20 Rainbow Pipeline

On April 28, 2011 Plains Midstream Canada experienced a pipeline failure on its 20” Rainbow Pipeline, approximately 95 km northeast of Peace River in Northern Sunrise County. The failure resulted in a release of approximately 28,000 barrels of crude oil.

In addition to the ERCB on-site incident response, ERCB technical staff began reviewing evidence related to the cause of the failure. A comprehensive review and assessment of Plains’ procedures and a third party engineering review that analyzed the cause of failure and Plains’ leak detection and response procedures has been completed. As a result of this review and assessment, a number of requirements and recommendations for improvement have been made and accepted by Plains.

Subsequent to the failure, several meetings were held between Plains and ERCB staff, along with numerous official requests to Plains for information to demonstrate that the pipeline could be safely returned to operation and operated within all regulatory requirements.

On May 17, 2011, the ERCB directed Plains to conduct two excavation programs to inspect weld-on sleeves on the pipeline and report results of those excavations to the ERCB. ERCB inspectors were on-site during these excavations.

On June 3, 2011, the ERCB directed Plains to retain the services of a duly qualified consultant to conduct a comprehensive engineering assessment that would provide engineering evidence supporting whether or not the pipeline would be safe to restart. Det Norske Veritas (DNV) was engaged by Plains and submitted a final report to the ERCB on July 27, 2011. The ERCB has reviewed and accepted the report.

The DNV report concluded the following:

  • the pipeline failed as a result of a crack in the circumferential fillet weld of a weld-on repair sleeve in the presence of an unusually high stress;
  • the initiating defect, or crack,  was formed at the time of installation of the weld-on sleeve (1980) by a mechanism known as delayed hydrogen cracking;
  • the source of the high stress that led to the failure of the defective weld has not been conclusively established; and
  • the stress that caused the failure could not have been caused solely by internal pressure or lack of support due to inadequate compaction of the backfill in April 2010. It is possible that the cumulative effect of sub-critical loads from various sources could have caused the weld failure.

As reported by DNV, sections of the pipe excavated as part of the assessment did contain very small cracks on fillet welds used to fasten weld-on sleeves. It was determined that these small cracks likely occurred at the time of repair, more than 30 years ago. Based on the information submitted by the company, the ERCB accepts that the failure was likely caused by an unusual combination of stresses acting on the weld defect. The ERCB also accepts that these small repair-related cracks, if repaired on an expedited schedule, pose minimal risk to the integrity of the pipeline. Plains has committed to excavating and inspecting all weld-on sleeves on the pipeline and making necessary repairs. The ERCB will monitor these repairs and meet with Plains on a monthly basis to discuss results. The report also contained a number of recommendations to improve operating procedures all of which Plains has committed to implementing on a timely basis.

On August 16, 2011, the ERCB issued a letter to Plains authorizing the NPS 20 Rainbow Pipeline to resume operation subject to various conditions.

Note to editors

The ERCB also notes that information it distributed on May 5, 2011 about a Bow River Pipeline spill in 1975 was incorrect. The ERCB has no record of a large-scale leak at a pipeline operated by or licensed to Bow River Pipeline in 1975. The incorrect name of the operator, the spill volume, and date were the result of a data search that was inaccurately generated in the days after the incident.

A full search of the ERCB’s electronic and papNoer records indicates that the largest recorded pipeline spill in Alberta occurred on December 5, 1980 in the Valleyview area on a pipeline operated by Peace Pipe Line Ltd. The total volume recorded was approximately 40,000 barrels.