Positive Operational LL with DNO

Oselvar (A-1 H, A-2 H, A-3 HT2) – P&A

What happened:

We discussed the option 1) of hanging the entire landings string with Wellsafe Explorer weak links, slickline BOP, Surface Flow Tre, Casing wear joint and the landing string in the blocks inside the derrick and the marine riser, or 2) break off the top heavy SFT and CWJ from the top of the 8 5/8″ casing landing string, and lay out the CWJ into the chute for riser joints. The landing string would then be sitting in slips. We discussed the two options, wrt to “wobbling” around of SFT and Wellsafe Explorer in the derrick during bad weather, and the danger for landing string hanging up again inside the marine riser if the Lower Marine Riser Package had to be disconnected (LMRP and marine riser then move up 6 m fast relative to the static landing string inside).

What was planned:

Suspend the landing string after disconnect subsea during a storm

What was learned:

The securing of the SFT and CWJ in the derrick worked very well. The whole assembly with two sets of bails was not moving around much even with high pitch and roll during the storm.

What actions are required:

Chose this solution if another disconnect and storm comes up during this P&A campaign.

What Was Done

It was decided to leave the landing string suspended in the blocks, hanging free down into the riser. The SFT was secured with 2 tugger wires and snatch blocks up in the derrick.