Negative Equipment LL with DNO

Norma (25/7-11 S) – Surface section

What happened:

From the start of the section after the FIT, delivery of cuttings to the ISO tanks using the CCBs proved problematic. Problem was traced to a faulty (partially-punctured) pneumatic seal on one of the (two) CCBs. 2.75 hrs were lost circulating clean and starting to POOH during troubleshooting the problem.

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What was planned:

To drill 17 1/2″ section with CCB cuttings handling, aiming for 80 m/hr on-bottom ROP.

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What was learned:

To change out the damaged seal requires an estimated 12-24 hours. Drilling continued, controlling on-bottom ROP to 50 m/hr due to the reduced efficiency of the CCB installation.

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What actions are required:

1. Review with MI Swaco the CCB installation design to evaluate what possible modifications could be made to allow easier and quicker replacement of the seal concerned if it leaks. 2. Review with MI Swaco project co-ordinator minimum stock levels as per contract of spare parts for the CCBs and evaluate if contracted minimum stock levels are being carried on the rig. 3. Review with MI Swaco project co-ordinator whether the seal involved should be subject to a planned routine changeout, and not replacement only when it fails.