Introduction to Coiled Tubing
What is CT?
Coiled Tubing (CT) has been defined as any continuously-milled tubular product manufactured in lengths that require spooling onto a take-up reel, during the primary milling or manufacturing process. The tube is nominally straightened prior to being inserted into the wellbore and is recoiled for spooling back onto the reel. Tubing diameter normally ranges from 0.75 in. to 4 in., and single reel tubing lengths in excess of 30,000 ft. have been commercially manufactured. Common coiled tubing steels have yield strengths ranging from 55,000 PSI to 120,000 PSI.
Key Elements of a CT Unit
The coiled tubing unit is comprised of the complete set of equipment necessary to perform standard continuous-length tubing operations in the field. The unit consists of four basic elements:
- Reel - for storage and transport of the coiled tubing
- Injector Head - to provide the surface drive force to run and retrieve the coiled tubing
- Control Cabin - from which the equipment operator monitors and controls the coiled tubing
- Power Pack - to generate hydraulic and pneumatic power required to operate the coiled tubing unit