Well Decommissioning – Starter Head Removal & Conductor Pull Hole Drilling

Customer: Operator

Location: North Sea, Offshore Platform

Well Decommissioning – Starter Head Removal & Conductor Pull Hole Drilling
Published in Machining


The challenge was to remove 41 redundant production Well ‘starter heads’ from the internal 18 5/8” casing strings, cut to be as near to the weld of the starter head and casing as possible.

Cutting had to be carried out internally due to tight access between the well-bay deck and distance required for the removal lifting method for the 26” & 18 5/8” conductor, eliminating standard external cutting.

With the starter head cut and removed, the scope required 2 off x 6.25” diameter holes to be trepanned / drilled through the 18 5/8” casing and the 26” conductor. 

For this purpose, a 6” pin was to be inserted for the initial pull of casing strings for decommissioning of the well.

Remove 41 redundant production well starter heads


Glacier Energy designed a bespoke ‘automatic feed’ internal casing cutting machine.  This achieved the client required cut depth inside the 18 5/8” casing. The design incorporate a quick mounting and self centring method to reduce set up time onsite.

Successful removal of production well starter head

Glacier Energy designed and manufactured a 26” conductor wrap-around mounting fixture to allow for 2 off drilling positions 180 degrees apart, site assembly before or after head removal as required.

Drilling was carried out using Glacier Energy original Dee-Drill machines and all equipment was hydraulically powered.

Successful offshore deployment and cutting was achieved under platform conditions.


  • The success of client focused trials (FAT) and demonstrations to establish actual cutting timescales has allowed for the scheduling of Glacier Energy's offshore work scope to be planned into the full well abandonment programme. This therefore reduces stand-by time offshore.
  • The equipment is serviced and containerised for short notice mobilisations, allowing the client to continue well abandonment operations on schedule.
  • The equipment is designed to allow for use on various OEM style wellheads which allows usage on most operators' well abandonment programs.

Successful removal of 41 starter heads

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