Negative Operational LL with Wellesley

Carmen (35/10-10S) – Surface section

What happened:

NPT: 1.25 hrs
Cost: 260 417 NOK
Downtime due to reaming and reduced ROP.
Drilled stand from 1633-1661 m at 50 m/hr (reduced from 75) and 3 t WOB due to build tendency of 0.2 deg/30 m. No change seen in build tendency.
Reamed stand (twice) from 1747-1775 m and from 1835-1863 m due to build tendency of 0.2 deg/30 m. No change seen in build tendency.
Drilled 17 1/2″ hole from 1921 m to 2167 m.ROP 41 m/hr. Reamed stand (once) from 1949-1978 m and (twice) from 2037-2065 m due to increase in build tendency from 0.2 deg/30 m to 0.5 deg/30 m. Build tendency reduced to 0.3 deg/30 m.

What was planned:

Drilling of 17 1/2″ without motor and only using rotary