Monitoring and Controlling Corrosion in an Aging Sour Gas Gathering System A Nine-Year Case History

Abstract

Abstract This paper details the challenges encountered in successfully treating this 45-year-old low- and high-pressure very sour gas gathering system in North Dakota. The existing gathering system has been owned and operated by several companies over the lifetime of the piping, and corrosion mitigation was not always a concern to each owner. Much of the low-pressure system was designed and installed in the late 1950s and early 1960s. Access points for monitoring and treating corrosion were not considered in the design and construction process. A result is that the lines have severe, localized metal loss in low spots, low flow velocities, and few access points, which makes delivery of corrosion inhibitor, maintaining line cleanliness, and monitoring the system difficult. The evaluation, modeling, treatment, and monitoring processes used to assess system conditions, to design and implement a treatment program, and to monitor corrosion are presented. The results of this nine year program include a sustained, significant reduction in failures and associated costs and are detailed.