Learning From Assurance
This week¿s Learning From Assurance is on Non-Shearables. The ability to shear is the last line of defense to prevent a blow out scenario and each operation must be able to demonstrate capability to shear drill pipe, work string and tubing (with any associated control lines / cables), as per SP-1213 section 6.9.2. However there is certain equipment that is run across the BOP for a short period, that is Non-Shearable; for example; BHA, Drill Collars, ESPs etc. This is also true for CWI operations when pulling a toolstring across a BOP/XT.
It is critical that the Driller/Operator/crew is notified of the shearability of all equipment run through the BOP/XT, along with a specific procedure to manage the risk for Non-Shearables, especially those that cannot be closed in against. This procedure should consider the exposure time in the level of controls, as well as the contingency plan with the actions to take if the well needs to be shut in. Particular attention is required for dynamic fill operations.
Each site shall ensure:
- The list of Shearable and Non-Shearable tubulars is posted in the dog house.
- Does the unit¿s HSE Case WPS bowtie include when Non-Shearables are across the BOP/XT? Are the Safety Critical Tasks / barriers understood?
- A risk assessed specific procedure is available for Non-Shearables across the BOP/XT (to be specific to the Non-Shearable tubulars or toolstring).
- A TBT is held prior to running Non-Shearables across the BOP/XT with reference to the procedures.
- The presence of the Toolpusher on the rig floor (or control unit) while Non-Shearables are across the BOP/XT.
- All personnel involved in the operation are clear on their responsibilities / actions to take if the well starts to flow.
- Drills are performed (and recorded) for Well Control scenarios where Non-Shearables are across the BOP/XT.
To reference the PDO standards:
Well Control Specification, use the following link SP-1213
Well Control Principles, Practices and Implementation Guidelines, use the following link GU-1035
To access more LFAs/PWRs from UWA activities please follow this link to UWD Knowledge Base KB.
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