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Ace Drilling Centralizer* Rotates on Liner, Provides Stability to Liner Drilling Directional BHA

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National Oil Company Selects Ace Drilling Centralizer (ADC)* to Stabilize 7” Liner Drilling String in Directional Interval

Casing and liner drilling are recognized as two of the best methods to minimize drilling problems and secure total depth of troublesome intervals. Both methods involve drilling with the casing or liner string with either a drill bit attached to the string or a retrievable BHA, which upon reaching total depth can be safely withdrawn through the string to isolate the BHA from hazards. 

Based on the most recent successes of the Ace Ratchet Collar (ARC), ACE have developed the Ace Drilling Centralizer (ADC), a centralizer that rotates independently of the casing or liner string.

This centralizer is developed for use in applications where many revolutions of the casing or liner string is expected.  Its use reduces drilling torque and minimizes wear to both the parent casing and the rotating casing or liner.  Applications include casing and liner drilling & reaming, and for rotating the string while cementing. To minimize drilling torque and wear on the liner and parent casing, the operator elected to run Ace Drilling Centralizers during its drilling test to evaluate their performance. 

The 7” ADC solid-body centralizer consists of a centralizer coupled with (2) Ace Ratchet Collars with extensions that fit under the centralizer.  The centralizer rides on these extensions to prevent wear on the casing or liner. The robust design is rated to 90,000lbs axial force and contains no small parts that can fail, leading to major issues.

The ADCs can be ordered with an outer diameter to match the hole size drilled.  In this case 8-1/4” was selected to run inside an 8-1/2” open hole. The design of the curvature of the blades and the bypass slots can also be varied to meet specific requirements.

The Result

The ADCs were installed onto the liner at the rig site by 1 trained installer, taking less than 10 minutes to install each centralizer assembly onto the pipe in the required location.  Just under 900’ of directional hole was drilled with the liner in 13-1/2 drilling hours.  The liner was rotated approximately 54,000 times at speeds ranging from 30 to 80 RPM, and was pulled at the end of the planned interval to recover all tools for evaluation.

This was the first run of the ADC for this operator, who is now pursuing further applications for this and other ACE products.

*Mark of Ace Oil Tools