Negative Operational LL with DNO

Oselvar (A-1 H, A-2 H, A-3 HT2) – P&A

What happened:

Landing string got stuck after pulling 7 m. Possible stuck with SSTT at marine riser flex joint, OR upper lubricator valve inside the slip joint, OR THRT in annular. Difficult to know, but main point is that a landing string can get stuck in the drilling BOP stack and the marine riser.

What was planned:

Disconnect the Tubing Hanger Running Tool from the tubing hanger, and pull the landing string up 13 m in preparation for a forecasted storm with rig heave over 3 m

What was learned:

The landing string can easily hang up inside the BOP and marine riser.

What actions are required:

Plan to pull landing string in good weather before rig heave comes up. Plan to pull upper completion (tubing) with drill pipe and mechanical tubing hanger running tool. Design top of lubricator valves and THRT with chamfered top shoulder that will not hang up.

What Was Done

Worked string up and down with max 10 MT overpull, while pulling rig on anchor chains in 4 different directions. Bullseye at riser flex joint was 0,5 to 2,0 deg during the event (pretty good). Got string past hang-up point after 1 hr and 20 minutes.