Negative Equipment LL with DNO

Oselvar (A-1 H, A-2 H, A-3 HT2) – P&A

What happened:

We pressure tested the BOP in an untraditional way using a BOP jump tool. This took very long time and induced more risk. The intitial plan was to tag the tubing hanger with the BOP jump tool, in order to act as a depth reference, for BOP space out. The dimensions from the BOP jump tool drawing was imported into a 3D drawing of the tubing hanger. It was found to be OK.

What was planned:

Test the drilling BOP after it had been disconnected. Both the LMRP and the BOP had been disconnected after bad weather. To test the LMRP/BOP H-4 connector the UA has to be closed around DP.

What was learned:

Pressure testing the BOP with the BOP jump tool is not recommended. Tagging BOP or wellhead items from a semisubmersible rig is bad. It is hard to control a tag to less than 5 MT.

What actions are required:

We have not planned for, or have equipment to pressure test the H-4 connector below the LMRP. Install a wearbushing in the tubing hanger, if it has to be tagged. Ideally get a BOP test tool that can be landed inside the HXT on top of the wearbushing. Need to ask Aker Solutions to supply this ASAP before well A2 and A1.

What Was Done

Just before the test, it was discovered that the actual dimensions of the physical BOP jump tool was different from the drawings. The tubing hanger could not be tagged without beeing damaged. Alternative plans were made, by tagging a closed MPR. A pipe ram should not be closed without pipe. The vertical tolerances were very small, and the rig heave was 2 m. If the MPR was closed with the BOP jump tool in the wrong place, we could have damaged the drilling BOP. The DP had to be blocked in the top, leading to a 61 MT force acting upon the pipe and up on the MPR during the test. This is not good.