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Ace Ratchet Collar replaces centralizer subs in the coast of West Africa - Senegal

Major Operator selects Ace Ratchet Collar (ARC) and Centek Uros CT bow spring centralizer as a viable alternative to costly centralizer subs in a close tolerance application.

Ratchet collars prevent centralizer movement
Ratchet Collar for faster running speeds


  • 11-3/4” SM125S SLIJ Liner run thru 13 3/8” 72# casing (12.347” ID)

  • Dual Centralizer setup

  • Cost savings between $80 - $150 000 USD

  • Liner successfully ran to total depth and cemented

The challenge

A 11-3/4” liner needed to be run and set inside a 13 3/8” casing above a 12-1/4” x 14-3/4” under reamed hole. The 11-3/4” string utilized flush joint connections. 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 12.347” ID of the 13 3/8” casing and to provide sufficient holding force. The operator also had the option to run two centralizers on each joint with the stop collar, to ensure proper standoff was achieved.


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 the major service company Halliburton, 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 13 3/8” casing string at a substantial cost savings versus the alternative centralizer subs.


The result


Forty (40) ARCs and twenty (20) centralizers were installed off-line at the pipe yard, on ten (10) joints. The pipe was sent to the rig then run down to TD of 2776 meters. The casing annulus was circulated clean and cement pumped as per plan.


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