Coiled Tubing Complete Guide
Coiled Tubing (CT) is a continuous length of small-diameter pipe that is spooled onto a reel in the same way as wire or cable is wrapped on a drum. The coiled tubing operation permits the technique of "snubbing" a continuous length of tubing in and out of a live well through a stripper BOP arrangement. The main advantage of Coiled Tubing is that it can be run into producing wells, against high wellhead pressures (e.g.
https://www.drillingmanual.com/coiled-tubing-complete-guide/