This research effort was designed to evaluate stress-oriented hydrogen-induced cracking (SOHIC) behavior of a broad range of advanced plate steels (0.002 wt% sulfur) that were not produced to enhance resistance to cracking in wet H2S environments. Test results indicated that SOHIC resistance was adversely affected by microstructural (ferrite/pearlite) banding. However, additional factors also played a role in determining SOHIC behavior.
Sour service behavior of a 110ksi material was investigated in a range of production environments. Slow strain rate tests were performed at a strain rate of 510-7/s, in sweet as well as in sour production environments. The strain to failure in sweet environments is lower than the in-air values and is substantially lower in the presence of H2S.
A corrosion cracking assessment evaluated a 13Cr-5Ni-2Mo 110 ksi grade martensitic stainless steel as a potential well tubing material for oil and gas production from Gulf of Mexico reservoirs. Also, Stress Corrosion Cracking at low H2S/low temp/high acidity (pH<3.5) was tested by Cyclic Slow Strain Rate.
The aim of this test program is to provide technical data to support the replacement of austenitic flexible pipe carcass, at Campos Basin, by low cost materials with suitable mechanical properties and corrosion resistance when the field conditions turn too aggressive to carcass materials in operation.
Subsea flowlines and risers experience fatigue cycles due to thermal and/or pressure transients or vortex induced vibration (VIV). Tests were performed under constant stress intensity factor (K) levels, in a mildly sour environment and in seawater under cathodic protection to understand the difference in the CRG.