Enhancing integrity: improving gas pipeline safety by using direct assessment

摘要

It's well known that internal corrosion in gas, liquid, and multi-phase transmission pipelines is a major problem which causes extensive damage to pipelines and operating facilities worldwide. The incidents caused by this issue have led to new regulations such as 49 CFR192 (Sub. O), which states that the threat of internal corrosion in a natural gas pipeline system is assumed to exist until an operator can demonstrate otherwise, either through direct assessment, in-line inspection (ILI), hydrostatic pressure test, or some other technology. This has led to a substantial acceptance of new direct-assessment and pipeline-integrity focused work by the industry. The National Association of Corrosion Engineers (NACE), for example, has ratified internal-corrosion direct assessment (ICDA) methods for dry-gas, wet-gas, and liquid-product pipelines to meet the need for pipeline integrity with respect to the likelihood of internal corrosion. ICDA is designed to prioritise the likelihood of corrosion along a pipeline and identify locations most susceptible to internal corrosion damage. These prioritised critical locations are then excavated and examined, and results of these inspections are used as the basis for assessing the integrity of the complete pipeline. In effect, inspection data from a select few locations along the pipeline is used to characterise the integrity of the entire pipeline. Performing successful ICDA relies heavily on the ability to model flow and accurately quantify/predict corrosion damage along the pipeline.