Coiled tubing has been traditionally characterized by its mechanical properties in order to guarantee that the structural response of the tubing is uniform and satisfies current standards along its full length. Also the tubing is generally fatigued tested in order to characterize its responses under simulated field conditions. As coiled tubing applications become more challenging, there is a need for higher mechanical properties, better resistance to severe environments and a better relative fatigue performance in the tube body and bias weld. The limitations to develop a product that satisfies these new requirements can not be understood solely based on coiled tubing mechanical properties, but extensive metallurgical analysis must be performed.
In this study, the relevance of the metallurgy basis in each of the production steps was reviewed in order to understand the limitations of current manufacturing process. This understanding, coupled with the goal of developing new products that satisfy new market demands, has resulted in a complete redesign of the manufacturing process. Preliminary results of a new manufacturing process have proven to provide a path for current and future innovative products.