Positive BOP LL with DNO

Oselvar (A-1 H, A-2 H, A-3 HT2) – P&A

What happened:

When pulling 13 3/8″ seal assembly on other wells the choke and kill line failsafes were open against a closed choke. The problem is there are swab cups inside the casing that create a trapped volume and as the seal assembly is picked up this string movement creates a trapped pressure that then has to be treated as coming from below the seal assembly until it can be proven otherwise.

What was planned:

Pull 13 3/8″ seal assembly free from wellhead with closed upper annular preventer.

What was learned:

The choke was left 50% open and then closed as soon as the seal assembly was pulled free to create a “soft shut-in”. This resulted in zero trapped pressure.
The lack of trapped pressure meant it was quicker to diagnose the forward steps to circulate the 13 3/8″ x 20″ casing annulus. Possibly 30-60 minutes were saved.

What actions are required:

Incorporate this learning in the as run DOP.

What Was Done

The choke was left 50% open and then closed as soon as the seal assembly was pulled free to create a “soft shut-in”. This resulted in zero trapped pressure.