NEWS Centek and Ace Oil Tools develop deepwater centralizer
Centek Group and Ace Oil Tools AS have jointly developed the CentrAce centralizer, designed specifically for use in tight-tolerance deepwater applications.
The CentrAce combines a low profile locked-on Ace stop collar with a close tolerance Centek centralizer. The unit is fitted like an over-pipe, and is pulled into the well by the casing weight, allowing rotation of the string as required. It is suitable for use in under-reamed wells and is ideal in wash-out sections, as the centralizer outer diameter is over-sized to the nominal bore hole. The CentrAce reduces dependency on subs, bringing major cost savings.
The CentrAce’s integrated Ace Ratchet Collar means only one stop collar is needed, unlike conventional stop collars which require two collars on either side of the centralizer. The ACE collar once tightened becomes part of the CentrAce centralizer and locks it in place. The stop collar comprises male and female components, which when pushed together with a hydraulic ratchet system lock a toothed ring onto the tubular. A race bearing coupling between the CentrAce centralizer and the stop collar allows the casing to be rotated as required within the centralizer.
When run in hole, the CentrAce unit is pulled through any restrictions reducing insertion forces and easing the deflection transition of the bows. The low friction and insertion force along with the low profile design means it can pass through the tightest tolerances. Because the casing can be rotated at the same time running force is further decreased greatly reducing the likelihood of loose or broken components down hole.
“Sub connector assemblies are very expensive because you have to machine both the male and female connections. The CentrAce gives cost savings as it can be speedily installed around the casing at the pipe yard or on a rig,” said Cliff Berry, Global Accounts Manager at Centek Group. “With a sub you can only fit one per casing length but with the CentrAce you can if required fit several units on the same length of pipe giving closer spacing and better centralization. This is ideal for preserving well integrity.”
The time taken to make up is reduced because compared to two standard stop collars, each with 10 screws to tighten, the CentrAce is clamped speedily into place. This speeds up installation in the pipe yard.
“The Ace stop collar is very low profile with a holding force much greater than a conventional stop collar,” said Ken Erik Steine, Business Development Manager at Ace Oil Tools. “We were able readily to adapt our collar technology to fit inside the CentrAce centralizer, producing an integrated unit with unmatched holding strength but which still leaves the casing free to rotate.”
Designed and manufactured by Centek and Ace Oil Tools, the CentrAce range is available in a range of sizes.