In-Plant Piping Hydrogen Induced Cracking Survey in a Gas Oil Separation Plant (Case Study)

摘要

A detailed survey of Hydrogen Induced Cracking (HIC) was conducted in a Saudi Gas Oil Separation Plant (GOSP). The piping system was not originally fabricated using HIC resistant steel and has been employed in wet sour crude and gas services for the last 24 years. This particular GOSP was built in 1982. It produces 300 thousand barrels oil per day (MBOD) of crude; and 100 million standard cubic feet per day (MMscfd) of associated sour gas. There were 170 pipe spools that were identified with HIC in the GOSP facilities using ultrasonic on-stream inspection (OSI). The objective of this survey was to inspect, monitor and identify severely effected plant piping to avoid occurrence of any catastrophic failure that could result from HIC damage. Indications of HIC, categorized as moderate to severe with continuous loss of back wall reflection, have been recorded for many pieces of equipment and piping spools.Additionally advanced ultrasonic examination (P-scan ultrasonic mapping), which is used to detect corrosion, laminations, inclusions, HIC/blistering and any defect between the outer surface and the internal surface, has been performed. This inspection was recently conducted on selected locations to provide more detailed information for a risk based assessment (RBA) review. Based on the result of this assessment, pipe replacement will be deferred by 2 years; and significant cost savings through production loss avoidance will be realized. Potential short-term repair measures, including full metallic sleeves and non-metallic composite wrapping, to extend the service life of the affected piping until the next scheduled test and inspection T&l, are being considered as alternatives if stepwise cracking develops in the future.