In order to establish barriers to enable a safe removal of a sub sea BOP, two temporary cement plugs had to be placed in the 10¾″ casing using 2″ coiled tubing (CT).

The operation was performed from a floating drilling/production semi submersible rig in 360 m water depth connected to the well by a marine riser.

A 23/8″ hole was milled through a BOP testing tool assembly (BTT), which had become stuck below the BOP due to a malfunction of a BOP ram, while containing well control throughout the operation.

A novel OBM formulation design was utilized in order to clean up the settled solids in the OBM in the well through the 23/8″ milled hole.

A novel cement packer was run down to 2000 m through the 23/8″ milled hole and set in the 10¾″ casing, allowing a successful cement plug to be placed in a 46 degree inclination at extremely low pump rate utilizing coiled tubing. A similar cement plug was set and tested at 900 m using the same method.

The whole operation was completed successfully considering that a lot of uncharted coiled tubing technology was utilized.

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