In this paper, a reassessment using the NACE International Standard Practice SP0116-2016 for Multiphase Flow – Internal Corrosion Direct Assessment (MP-ICDA) protocol was conducted for the first time on three pipelines which were originally assessed in 2011 using the NACE International SP0208-2008 Liquid Petroleum ICDA (LP-ICDA) methodology. The LP-ICDA and MP-ICDA methodologies were compared in the reassessment. The paper discusses how the new data and the previous LP-ICDA 2011 data was integrated. Notwithstanding, the pipeline did not undergo any significant changes since the previous assessment approximately 8 years earlier. However, the use of the MP-ICDA protocol revealed new information regarding additional internal corrosion threats which the previous LP-ICDA protocol did not capture. This paper also details how the 2011 and the current 2019 Detailed Examinations were compared to enhance the accuracy of forecasting corrosion rates, despite using different excavation sites. New information revealed by the MP-ICDA reassessment, led to recommendations that would further reduce the possibility of general and pitting corrosion going forward and thereby potentially prolong the life of the subject pipelines.
The Kuwait Oil Company subject CR102, CR103 and CR104 pipelines were commissioned in 1959 for transporting crude oil from the North Tank Farm Loading/Gravity Manifold to the Crossover Manifold over 7.3 km (4.5 mi). The three pipelines run directly parallel to each other a few meters apart for the entirety of their length. All subject pipelines are constructed from 1,219.2/965.2 mm (40/38 in) diameter 11.1 mm (0.43 in) wall thickness API 5L Gr. B spirally welded carbon steel pipe externally coated in coal tar enamel. No internal coating or corrosion inhibitor were used.1,2
Liquid Petroleum Internal Corrosion Direct Assessment (LP-ICDA) (SP0208-2008) was originally performed on the subject pipelines by Allied Engineers(3) and Broadsword Corrosion Engineering Ltd.(4) (and the same firms were retained for the current reassessments) for the operating period of 1959 to December 2010.3,4 This means the current ICDA, which follows the Multiphase Flow ICDA (MP-ICDA) (i.e., NACE SP0116-2016) protocol, is a reassessment after eight (8) years from January 2011 to October 2018.5 Following the transition between LP-ICDA to MP-ICDA for a more thorough re-evaluation, comparisons were made between the new and old data to indicate some important changes to the crude. The complete MP-ICDA process consists of: Pre-Assessment (PreA), Indirect Inspection (IDi), Detailed Examination (DEx) and Post-Assessment (PoA). This paper reviews the 4-step ICDA process performed in late 2018 and early 2019 and discusses the recommendations provided for prevention and/or mitigation steps to be taken to mitigate the expected corrosion and/or pitting in the subject pipelines.
