• Published: 26 May 2011
  • Incident ID: 3171

C-Annulus Over-Pressurisation

Cause & Consequence

  • Failure of vessels or pipework
Incident Consequence

Incident Location


Incident Activity

Production operations

Incident Info Source

Heidi Mykland, Shell Exploration and Production

Specific Incident Equipment

No details available

Lessons Identified

- Thermal expansion happens rapidly on PWRI wells due to temp < 90degC.- Increased monitoring of annuli is required after AITs, especially if well offline when AIT carried out.

Incident Recommendations

- Remote monitoring of C annuli to be installed if practical.

- Platform Operating Procedures to be updated to ensure that they include increased annuli monitoring on start up, after AITs and when bringing on PWRI wells.

- Raise awareness of platform crews on the importance of Annuli monitoring.

- Review frequency of routine C annuli monitoring to ensure that it is adequate.

- Review C annuli monitoring procedures.

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