Other Equipment LL with DNO

Norma (25/7-11 S) – Reservoir section

What happened:

While sampling the MDT Saturn probe got stuck. All attempts to free with wireline tension, cycling probes, jarring……all failed. The electrical release for the wireline, which would have allowed a “conventional” fishing attempt with overshot on drillpipe, failed to release when attempted. This dictated that a third party side-door overshot be used to strip over the wire and successfully retrieve the stuck toolstring.

What was planned:

Run MDT wireline toolstring to acquire reservoir pressure and take samples.

What was learned:

1. Plan on the basis that every time the MDT is run, there is a high likelihood of it getting stuck – whichever sampling probe is used, but in particular the Saturn probe. The risk is the price paid for acquiring the information.
2. Plan on the basis that when the above happens, the electrical release may not work. There is no mechanical weak-point back-up – so we need to have the side-door overshot mobilised every time (as was done in this case).

What actions are required:

Discuss with Schlumberger (insist ??) that they provide the side-door overshot assembly and grapples. They currently provide excellent fishing equipment (cut lip guide, overshot and grapples) to be used when the electrical release works. It is useless when the electrical release fails.
The side-door overshot and grapples should be part of the load out with the MDT tool, managed and run by the Schlumberger operators.