Positive Operational LL with Wellesley

Schweinsteiger (6204/11-3) – Top hole

What happened:

Due to shallow gas zone at 331m, needed to fill casing with mud to be ready in case of need to wash down and ensure that gas zone in annulus would not be at risk of flowing if exposed to seawater again. Needed also not to waste mud.

What was planned:

Run 13 3/8″ x 20″ casing filling with seawater.

What was learned:

Performed calculations to understand 1.25 SG mud volume required every 5 joints to balance 1.03 SG seawater hydrostatic while running to seabed. Flew ROV to observe shoe joint while filling and stopped pump when mud seen flowing through shoe, proving hydrostatic inside and outside thew casing equal. Once 13 3/8″ shoe stabbed into seabed, used ROV to observe overflow from 30″ LP WHH once casing filled.

What actions are required:

Use same practice if we ever have to do this again…..