WE Report

Lessons Learned

Lesson Learned





By: Drilling Supervisor

Report No.

2324

Discipline/Origin

Drilling
Own Experience

Well

Hemispheres
36/1-4

Date created

2021/12/24
1444 days ago

Project Phase

Operational
Project Phase

LL Type/Classification

Operational
Other

Borgland Dolphin


What happened in Top hole:
30″ conductor and cement was cleaned out with seawater and sweeps, hole displaced to 1.40 SG WBM.
Drilling commenced with 3000 lpm and an apparent loss rate of 45 m3/hr over 10 mins observed.
Well flowchecked, static. Checked all surface equipment, all OK. Shakers were still gumbo laden from drilling cement with seawater. Staged up in 500 lpm increments to minimum flowrate for MWD, 2600 lpm and commenced drilling ahead.

What Was Planned

Drill 17 1/2″ section with 1.40 SG Glydril WBM starting with 3000 lpm.

What Was Learned

With cold new mud, better to start in this manner staging up and confirming pit levels at each stage before drilling ahead.
RMR flowmeter can be used to cross-check that volume pumped downhole by rig pumps matches mud volume returned from seabed to pits.

What Actions Are Required

Add stage-up procedure described to 17 1/2″ DOP after displacing to WBM prior to drilling ahead.
Add reminder to DOP that RMR system has flowmeter which can be used to cross-check volume pumped downhole by mud pumps in case of apparent losses.

EDITOR


CLOSE LL (testing)





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