Fatigue resistant coiled tubing

摘要

The disclosed manufacture method for a length of tubing can produce a length of fatigue resistant tubing that has relatively high fatigue resistance and relatively low strip-to-strip welding length. The Fatigue resistance is calculated from experimental settings with controlled parameters and/or simulations reproducing similar material properties and loading conditions. A high fatigue resistance means certain product characteristics (e.g., low plasticization, low hydrostatic stress levels and free of imperfections welds) can be retained with an adequate bias weld design at low values after a specific test number of cyclic loading. The relatively low strip-to-strip welding length is an advantage for reducing probabilities of having cracks initiated and/or propagated at weld locations, where imperfections and localized differences of mechanical properties commonly cause failure. Low strip-to-strip welding length can also reduce the costs for welding.