SPE Drilling & Completion
Volume 24, Number 1, March 2009, pp. 191-199

Summary

The failure of a primary barrier on a completed high-pressure/high-temperature (HP/HT) well in the west Franklin field in the UK continental shelf in 2005 resulted in a significant pressure increase in the production annulus requiring a complex well-kill operation to resolve. Following this incident, an investigation program was undertaken to determine the root cause of the failure and, thereafter, to develop a solution. The failure investigation looked at all aspects of the well design and operations and found no clear cause. A "failure test" then was carried out that recreated the exact downhole conditions on surface. This test demonstrated that very small irregularities in the internal-casing profile would cause the packer casing seal to fail under severe bottomhole conditions. A program then was undertaken to develop a packer-seal system, suited to the severe well environment, that could withstand a specified degree of casing irregularity. A rigourous qualification program also was developed to verify the new systems capability in irregular casing.

The program was completely successful, and new packer-seal systems have been qualified to these enhanced standards and deployed in the field.

© 2009. Society of Petroleum Engineers

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History

• Original manuscript received: 7 November 2006
• Meeting paper published: 20 February 2007
• Revised manuscript received: 21 January 2008
• Manuscript approved: 10 April 2008
• Published online: 16 March 2009
• Version of record: 1 March 2009