Jeremy Moloney

6 – Sour corrosion

Sour corrosion has been a major problem for the oil and gas industry for more than half a century. Despite comprehensive research efforts, prediction and mitigation of localized corrosion in pipelines and process facilities remain challenges that require further research. The current understanding and knowledge gaps of sour corrosion mechanisms are discussed in this chapter, including the effects of iron sulfide layers, elemental sulfur, steel microstructure, and other critical parameters.

Under-deposit corrosion

Internal corrosion mitigation of oil and gas pipelines in the presence of solids and debris has long presented challenges to operators. This chapter summarizes select research conducted on corrosion mechanisms and key factors involved in under-deposit corrosion (UDC). After considering the impact of the type of deposit itself as well as the galvanic and environmental effects that expedite this type of localized corrosion, experimental methodologies used to evaluate UDC are reviewed, before mitigation strategies are discussed. Although several models are available for estimating general corrosion as well as various forms of localized corrosion such as top-of-the-line corrosion, there appears to be limited activity in modeling UDC, which should be a focus for continued future research.

Accelerated Stainless Steel 316L Material Compatibility Assessment of Chemical Products Using Potentiodynamic Polarization

Over the past few years, there have been several instances in the oil and gas industry of incompatibilities and failures of stainless steel components carrying or containing chemical products. Material of construction compatibility with chemical products is a vital assessment to ensure asset integrity of critical components is maintained during field operation. The focus of this paper is on the evaluation of neat chemical product compatibility with stainless steel 316L (SS316L, UNS S31603), a commonly used alloy for storage tanks and umbilical tubing. A typical approach to assess the compatibility of stainless steel with neat chemical products involves using a weight loss immersion corrosion test methodology. However, this procedure has the inherent limitation in that it can take a long time to conduct, while data interpretation can be difficult because the induction period for pitting is unknown. This paper presents and discusses data from accelerated stainless steel compatibility tests of various neat c...