Materials Performance is the world's most widely circulated magazine dedicated to corrosion prevention and control. MP provides information about the latest corrosion control technologies and practical applications for every industry and environment.
Issue link: http://mp.epubxp.com/i/123600
S P E C I A L F E AT U R E Managing Corrosion of Pipelines that Transport Crude Oils separated out before the crude oil enters the transmission pipeline. Moghissi: The most common way to predict susceptibility to corrosion is to determine water content (usually measured as BS&W;) and compare pipeline throughput to the critical entrainment velocity. Consideration can be given for the water chemistry, presence of corrosion inhibitors (including both carryover or injected), any biocide treatments, and whether the pipeline is pigged. Ultimately, the existence of corrosion damage can be verifed by methods such as inline inspection (ILI), pressure testing, and/or internal corrosion direct assessment (ICDA). Each of these methods has different strengths and weaknesses. Papavinasam: The industry assesses the susceptibility of oil transmission pipelines to internal corrosion by two processes: direct assessment and ILI. NACE SP0208- 2008 documents the use of the direct assessment method and proposes a four-step process to identify the causes of corrosion in oil transmission pipelines: pre-assessment (collect and analyze pipeline operating data); indirect inspection (identify locations susceptible to corrosion based on operating data collected); direct inspection (inspect the locations predicted to be susceptible to internal corrosion); and post-assessment (establish the frequency of subsequent inspections). NACE SP0208-2008 also lists several models that can be used to predict the location of water accumulation in the indirect inspection step. Currently, NACE Task Group 477 is developing a standard report to provide guidelines for selecting the most appropriate model for this purpose. NACE SP0102-20103 provides guidelines to perform ILI where instrumented tools (commonly known as intelligent pigs) are sent through the pipeline for determining the remaining wall thickness of the pipeline. Mosher: ILI tools, such as magnetic fux leakage (MFL), ultrasonic testing (UT), or a combination of both, give the pipeline operator a "snapshot in time" of the internal and external condition of their pipeline. Corrosion features over a certain threshold are measured by the instrument as it passes through the pipeline. In addition, the location of the pig is recorded using a global positioning system (GPS). The tool gives the location of any anomalies detected along the length of the pipeline inspected. Anomalies of signifcant size/depths will often be validated by an excavation of the pipe. Often operators will use sequential ILI runs to predict the corrosion rates of anomalies and schedule future ILI runs based on their calculations. Other methods of identifcation include the NACE protocol Meet the Panelists Jenny Been Jenny Been is a corrosion specialist withTransCanada Pipelines (Calgary, Alberta, Canada) in the Pipeline Integrity Department, where she focuses on crude oil corrosion, risk assessment, and stress corrosion cracking. Been has more than 20 years of experience in corrosion control. During her career, she established a pipeline corrosion management industry working group focused on monitoring and mitigation of pipeline corrosion, has provided technical support to the National Energy Board's Pipeline Integrity Management Program, and developed pipeline integrity management manuals for pipeline operators. She currently serves on the NACE Board of Directors and has held leadership roles for several NACE technical committees. She attended the University of British Columbia where she obtained degrees in chemical engineering and a doctorate in materials engineering. 32 MATERIALS PERFORMANCE May 2013 Oliver Moghissi Oliver Moghissi is director of the Det Norske Veritas (DNV) Materials & Corrosion Technology Center (Columbus, Ohio). His personal experience is focused on developing and applying technology to optimize corrosion management programs, especially for oil and gas production and transportation facilities, and includes optimizing corrosion control programs, developing corrosion evaluation methods, and implementing corrosion technologies for life extension and regulatory compliance. He has chaired a range of NACE technical and administrative committees and received the NACE Presidential Achievement Award in 2003. He served as president of NACE for the 2011-2012 term. Moghissi received a Ph.D. in chemical engineering from the University of Florida and M.S. and B.A. degrees from the University of Virginia. Michael Mosher Michael Mosher is a professional engineer at Alberta Innovates-Technology Futures (Devon, Alberta, Canada) in the Advanced Materials Portfolio. Mosher has extensive expertise in pipeline corrosion and the majority of his work has focused on internal corrosion of crude oil transmission pipelines. Currently, Mosher leads an industry working group on pipeline integrity and corrosion management that is focusing on pipeline corrosion control systems for monitoring internal corrosion and developing mitigation strategies to reduce operating risks associated with pipelines as well as provide operational best practices and guidelines to the industry. He received a master's of applied science degree in materials engineering from Dalhousie University. NACE International, Vol. 52, No. 5