CDC™ Undereamer


CDC™ Undereamer

The WellEnTech CDC™ Underreamer is suitable for various downhole operations. It is a high expansion device and has an uninterrupted through bore. Depending on which blades the tool is dressed with will determine what OD the reamer will open out to. It can be deployed on either jointed pipe with a top drive or on coiled tubing with a PDM motor. The tool has three cutting blades which provide stability during operation. The large internal piston ensures maximum load is applied to the blades throughout the operation and a powerful spring pulls the blades back into the body when flow is stopped. Interchangeable blades provide a range of reaming diameters.


  • Short, compact design
  • Triple blade arrangement
  • Through bore
  • Blades and nozzles are easily removed and replaced
  • Blades can be redressed and reused
  • Assembled/dis-assembled using standard hand tools
  • Field redressable
  • Underreaming
  • Wellbore cleanup operations
  • Anchoring

The CDC™ Undereamer is generally run on a BHA below a motor but can also be run on jointed pipe. Flow down through the tool and out through the internal nozzle creates a pressure within the tool which acts against the piston. As the piston moves up within the tool, milled pockets which surround the blade pushes against them resulting in them pivoting about hinge pins. When fully open the blade is fully supported against a stop shoulder and wedge. When the operation is completed and flow is stopped, a spring within the tool returns the piston which simultaneously retracts the blades.


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