Abstract
Reservoir souring, as a results of water or steam injection, may lead to the exposure to sour conditions of systems which were not designed for sour service. Stress corrosion cracking (SCC), hydrogen embrittlement cracking (HE) and hydrogen induced cracking (HIC) are potential threats to the integrity of systems exposed to such conditions .
Approaches are outlined for the assessment of both the fitness–for–future–operation and the limiting operating conditions for such systems, focussing on SCC and HIC.
A method for the selection of appropriate SCC and HE tests based on slow strain rate testing (SSRT) is reviewed. The SSRT is used to determine operating conditions under which materials are not susceptible to SCC and HE. The fitness for further service of defect-containing equipment is determined on the basis of crack growth rates and maximum allowable defect sizes, maximum allowable crack tip opening displacements (CTODs), determined under the relevant environmental conditions.
New materials to be applied in sour service are selected on the basis of standard HIC and SSR tests. For existing equipment the limiting environmental conditions for HIC can be determined using the threshold hydrogen concentration concept. A novel approach to estimate this threshold from the inclusion size is indicated.
