The industry has experienced difficulty in establishing the use of coiled-tubing drilling (CTD) in the offshore environment. Numerous projects have been tried, but a commitment had not been made until recently to test this method in a controlled way, to further the learning curve and realize the potential of CTD offshore and in accessing bypassed reserves. In the South China Sea, Petronas Carigali contracted Schlumberger for a pilot project with the primary objective of bringing proven technology to the offshore environment to access small, bypassed reserves economically and to offer an alternative to conventional drilling. The offshore environment of the South China Sea has a large number of candidates for this type of pilot on existing installations. With the lessons learned from this pilot project, CTD was proven as an effective, alternative re-development option to access bypassed reserves in mature fields.