Effect of various fluids on insulated seamless pipelines on Corrosion Under Insulation (CUI) level in Remaining Life Assessment (RLA) determination using Lixi Profiler method

One Enhanced Oil Recovery (EOR) cycle involves two types of seamless pipes with different fluids: steam and crude oil. The pipes are insulated so Corrosion Under Insulation (CUI) can appear. CUI is one of the biggest corrosion problems in carbon steel materials that could impact production and cause economic losses. In determining the life of the pipe using certain standards, even pipes with different fluids have different standards, methods, and results. This research analyses the effect of various fluids in insulated seamless pipelines on the corrosion rate to determine the pipe's Remaining Life Assessment (RLA) using the Lixi Profiler. By knowing the location of the CUI anomaly and analysing the minimum thickness of photons emitted using Gadolinium153, verification can be done using pitting gauge. Inspections were conducted on an 8-inch steam pipeline and a 6-inch crude oil pipeline. Lixi Profiler scanning results showed a significant difference in the graph of the steam pipe which was more stable than the crude oil pipe due to the radiation absorption quantity. It is found that the remaining life of the steam pipe tends to be safe, while the crude oil pipe has the lowest remaining life in the range of 0-2.7 years and is recommended to be treated. The identification results of external corrosion on crude oil pipelines and steam pipelines are pitting corrosion with depths ranging from 0.26-2.95 mm and CUI of 0.39-1.68 mm, respectively. This proves that the corrosion rate of crude oil pipelines is higher than steam pipelines because they have more fittings, smaller pressures, and lower operating temperatures tend to have higher corrosion rates. (author)