Laboratory sulfide-stress-cracking(SSC)tests were performed on specimens taken from a QT-900 coiled-tubing(CT)test string to define zones of acceptable sour service.SSC tests were performed at room temperature in a brine-fluid environment with H_2S partial pressures ranging from 0.145 to 145.0 psi and pH levels from 2.8 to 4.5.The effectiveness of a new inhibitor for crack prevention was tested.SSC testing,which included Natl.Assn.of Corrosion Engineers(NACE)Method A tensile,four-point bent-beam(FPBB),and slow-strain-rate(SSR)test specimens,was performed on as-milled as well as fatigue-cycled tubing.
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