Coiled Tubing String Longitudinal Properties

Abstract

fax 01-972-952-9435. AbstractThis paper discusses test results of material properties along the length of a coiled tubing (CT) string that was manufactured in 1997. The 1.50-in. OD, 0.102-in. WT, 9,052-ft CT sting was made from 80-ksi yield strength material. The new string was manufactured with conventional procedures and was cut into 362 25-ft segments. The segments were properly numbered, protected against corrosion, and stacked. Among them, 128 segments were chosen for testing.Samples from the test segments were prepared for fatigue testing and tensile testing. Fatigue testing was performed with a bending machine having a 48-in. bending arch and 4,000-psi internal pressure. Tensile testing was performed with full-body specimens to determine yield strength, ultimate tensile strength, modulus of elasticity, elongation, and reduction of area.A total of 252 samples were tested. Test data are statistically analyzed, and their distributions along the length of length of the CT string are plotted. The results are compared with correspondent specifications and standards.