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Ace Ratchet Collar provides cost-effective solution in tight tolerance well

Operator selects Ace Ratchet Collar (ARC) and Centek UROS 1-piece centralizer as the preferred solution to costly centralizer subs on a shallow water well in Mexico

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  • Thirty (30) ARCS installed on 9-7/8” casing

  • Casing run thru 11-7/8” 71.80# liner (10.711” ID, 10.625” drift)

  • Casing run to total depth and cemented without incident

The challenge

A 9-7/8” casing string had to be run in to 10-5/8” x 12-1/4” open hole through both 13-3/8” casing and an 11-7/8” liner. The 9-7/8” string utilized flush joint connections.


A reliable slim stop collar was required to prevent slippage of the centralizers during run-in and while cementing. Considering flush joint casing connections, it is especially critical for the stop collars to prevent the casing accessories from slipping and collecting above the 11- 7/8” liner during run-in and to hold the centralizers in place while cementing to deliver the calculated stand-off.

The solution

Since the Ace Ratchet Collar (ARC)* resists high axial loads, while meeting drift requirements of the 11-7/8” liner, it was selected as the fit-for-purpose solution to prevent movement of the centralizers.

The patented slim ARC is rated to over 90,000lbs axial load and is specifically designed for close-tolerance applications. It can pass tight restrictions and effectively manage surge and swab, allow for faster running speeds in formations with narrow mud margins. The ARC also offers substantial cost savings as each unit is easily installed off-line and does not require pipe preparation or transportation off-site for installation.


The result

Thirty (30) ARCs and the centralizers were installed off-line by trained installers at the service company location within a few hours. The liner was shipped to the rig then run in the hole through both the parent casing and 11-7/8” liner, to total depth of over 4300m and 20° inclination. The casing annulus was circulated clean and cement pumped as per plan.

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