Importance of Quality Control and Positive Metal Identification (PMI) in the Oil and Gas Industry at the Component Fabrication or Repair Stage

摘要

In the oil and gas industry non-conformances and lack of quality control such as mix up ofmetallurgy and the use of non-NACE compliant material are sometimes encountered at thecomponent fabrication or repair stage which may go unnoticed for years till a problem occurs.From a corrosion point of view, some of these non-conformances may not be detrimental.However, the presence of fabrication defects, which may open up after years of service cancontribute to major failures resulting in unscheduled shutdowns, production loss,environmental contamination, as well as health and safety hazards.This paper highlights two such cases: (1) the SOHIC failure of a non-NACE compliant Tfittingin a sour crude pipeline, and (2) the cracking of a weld joint in a crude pipeline where asection of low alloy piping was welded to the carbon steel piping. Both failures lead tounscheduled shutdowns. In both cases, during the component fabrication stage, materialswere used without verification of the metallurgical status of the alloy, or the composition of thecomponents through Positive Metal Identification (PMI). Additionally, there was a lack ofproper understanding of the impact of non-conformance or quality control on the integrity of thepipelines during service.