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Ace Ratchet Collar meets deepwater challenges in US Gulf of Mexico

Major GoM Operator selects Ace Ratchet Collar (ARC) and bow spring centralizer as a viable alternative to costly centralizer subs in deepwater

ratchet collar centralizer for deepwater operations
Overcoming deepwater challenges with ratchet collar


  • 13-3/8” Q-125 liner run thru 16” 97# casing (14.750” drift)

  • 8000’ water depth

  • ARC capabilities unaffected by 40°F mud line temp

  • Liner run thru 3.0°/100’ DLS and set in 17-1/2” open hole at > 70° inclination

  • Liner successfully ran to total depth and cemented

The challenge

A 13-3/8” liner needed to be run and set inside a 16” casing above a 14-1/2” x 17-1/2” under reamed hole. The 13-3/8” string utilized flush joint connections and was run through the subsea wellhead in 8,000ft of water. The operator had to be confident of the holding capability of the tool they selected under all operating conditions to prevent casing accessories from coming loose, possibly sticking the liner or causing junk in the hole.

A stop collar with a slim design was needed to pass through the 14-3/4” drift of the 16” casing and to provide sufficient holding force. This is especially critical when passing through the wellhead restriction at the mudline, where centralizer insertion force creates the highest load on the centralizer.

The solution

The patented slim ARC is specifically designed for close-tolerance applications to both pass tight restrictions and effectively manage surge and swab, allowing faster running speeds even in formations with narrow mud margins. Each unit is easily installed off-line and does not require pipe preparation or transportation off-site for installation.


Through a major service company, Ace Well Technology provided the Ace Ratchet Collar (ARC) as the fit-for-purpose solution to prevent centralizer movement while running in hole. The ARCs are rated to minimum 90,000lbs to resist high axial load while meeting pass-through requirements of the 16” casing string at a substantial cost savings versus the alternative solutions.

The result

Thirty (30) ARCs and the centralizers were installed off-line by trained personnel at the pipe yard. The pipe was sent to the rig then run-down hole through the subsea wellhead located in over 8000ft of water to total depth of over 12,500’ at 70° inclination. The casing annulus was circulated clean and cement pumped as per plan.

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