Casing Backoff tool

Brand: Schlumberger
Product Code: Casing Backoff tool

Casing Backoff tool

Performs Casing Backoffs in horizontal and vertical wells

The casing backoff tool facilitates backoff of uncemented casing stumps at a selected coupling location downhole after a section has been cut and retrieved. The tool is effective in vertical or horizontal wells. The tool features nine subassemblies, including two hydraulic anchors and a torque generator. The hydraulic anchors allow the backoff tool to be used in horizontal wells because drill collar weight is not required to hold the anchors open. The tool is cycled, and, using hydraulic pressure only, the torque generator and anchors work in tandem to breakout and unscrew the casing threaded connectors with approximately one-half turn per cycle. When connection torque is sufficiently lowered, the backoff tool is pulled out of the hole, and a casing spear is
run to complete the unscrewing and recovery of the casing stump. A threaded connection remains downhole for the new casing string to be stabbed into and made up.Schlumberger can also supply subs for aligning the old and new casing strings to facilitate proper makeup downhole.

Fishing&Sidetracking Services
Replacing worn or damaged sections of uncemented casing, in vertical or horizontal wells.
  • Provides backoff solution for horizontal wells
  • Simplifies operations by eliminating need for left-hand drillstring.
  • Facilitates operations by leaving threaded connection for re-engaging new casing string after worn casing is removed
  • Supports further drilling by eliminating reduced casing drift diameter resulting from internal casing patches
  • Contributes to operational safety by maintaining original casing strength and integrity
  • Hydraulic anchors eliminate need for drill collar weight to achieve backoff
  • Tool generates up to 60,000 ft.lbf
  • Tool design eliminates need for overtorquing connections in a left-hand workstring on a “blind” backoff from surface

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