Abstract
Coiled-Tubing (CT) integrity remains at the forefront in the mind of end users, particularly in high-end applications. The properties of a CT string, including ovality and wall thickness, change over time when it is run into and is pulled out of a well, due to a number of wear factors and a combination of them, including well trajectory, fluid properties, the CT properties and the applied external forces.
A typical CT string is exposed to a variety of applications during its lifetime, each having a different effect on the material. Ovality and wall thickness loss thus become critical telltale indicators for the condition of the pipe and its potential serviceability. Devices for ovality and wall thickness measurement, whether performed off-line or real time during a job, are readily available.
This paper demonstrates how one such device has been used for various services with CT, including acid stimulation work in Saudi Arabia, CTD work in Alaska, Nitrogen kick off, clean out and CT spooling in Columbia and extensive eLine operations in the Barnett Shale, Texas. These case studies will show the evolution of material loss and ovality and how the information can be used to monitor and maximize the life of the CT string in a way that no other technique or model is capable.
