Drilling with coiled tubing will never replace drilling with rotary rigs. Rigs must be used on wells that require large-diameter holes and heavy, large-diameter pipe. Coiled-tubing drilling is designed for smaller-diameter, slim-hole wells that flow at less volume. Most of the coiled-tubing wells drilledtoday are sidetracks. These are wells that are drilled off of an older wellbore. Since the infrastructure of the older wellbore can be used, significant cost savings are achieved.