Negative Operational LL with DNO

Oselvar (A-1 H, A-2 H, A-3 HT2) – N/A

What happened:

DONG handover documentation: When drilling 8-1/2″ with 9-1/4″ underreamer a section of the hole was not underreamed due to underreamer malfunction. This was only discovered because the underreamer wore out further down the section and a check run was made with a new underreamer all they way (the calliper in the BHA is positioned between bit and UR).

External Actions

When circulating at TD, position string so calliper can verify ID’s above and below UR shoulder. If tight sections are experienced when POOH then evaluate to take calliper readings (realtime or memory) to confirm ID / that section has been underreamed.