The presence of high concentrations of acid gases (H2S and CO2) in combination with produced water and elemental sulfur will normally require that a corrosion resistant alloy (CRA) is selected as the material of construction for such oil & gas production facilities to ensure long-term pressure equipment integrity and reliability. This paper presents a 30+ year history of an asset with excellent mechanical integrity and reliability despite using carbon steel in the presence of wet gas containing 5% H2S 65% CO2 and elemental sulfur. This history includes a review of internal corrosion management data such as chemical qualification/injection history corrosion inhibitor residual analysis corrosion rate monitoring trends and continuous improvement efforts.Lessons learned are also provided to illustrate the evolutionary nature of the process that lead to the robust corrosion management program described herein. Key success factors such as robust corrosion control program design and field implementation continuous improvement through frequent review of monitoring data excellent leadership support and a multidisciplinary team approach are described.

Failure of water/wastewater mains can result in high visibility repairs customer inconvenience and replacement costs. Preventive measures such as condition assessment for early recognition of corrosion in aging infrastructures is crucial for agencies from resiliency safety and economic standpoints but is not regulated as in the oil & gas industry. Internally deployed tools/technology or external excavations for direct assessment techniques provide valuable insight on the existing condition of buried structures but at a significant cost in terms of shutdown and technology expenses in addition to safety concerns for manned entries into confined spaces. Because of the cost and safety implications large diameter cement mortar lined (CML) pipe extensive and recurring direct assessments are less common in the water and wastewater industries. Indirect assessment techniques particularly the over-the-line potential surveys for condition assessment of water/wastewater lines can be conducted to determine active external corrosion areas. Traditionally over-the-line potential surveys were applied to electrically continuous pipelines. Most water/wastewater pipeline designs utilize rubber gasket bell-and-spigot joints. Unless electrical continuity is intentionally designed for the pipeline such joints result in a pipeline with no electrical continuity. This paper presents multiple case studies where over-the-line potential surveys were successfully applied on electrically discontinuous water pipelines. The results of over-the-line surveys correlated well with direct assessment techniques. The paper presents the methodology and results of such assessments and findings for various pipe materials.

When a paralleling power line or pipeline route has been committed to close to an existing utility the induced AC (IAC) mitigation engineer may be seveely limited in the techniques available to adequately ground the pipeline(s) where required. Such was the case on a recently completed 220 kV wind farm transmission line in southern California. Very extensive computer modeling was required to find acceptable grounding techniques and practices on the four large diameter natural gas pipelines that were affcted by the 220 kV circuit. Work was divided into two phases so that the initial wind farm load could be safely transmitted before the complete mitigation package could be constructed. Design and construction of the phase 2 mitigation system required well over a year to complete and seiously delayed adding additional generation to the circuit.