Decommissioning and abandonment

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Decommissioning and abandonment

Cleaning

CLEANING

CLEANING

ƒ Cleaning required to remove deposits from pipe wall ƒ Wax, gas dust, scale, asphaltenes ƒ Internal LSA (NORM) scale ƒ Cleaning by running through trains of pigs ƒ Trains consist of foam, batch, brush and scraper pigs as required ƒ Most likely done before water filling (avoid problems of contaminated water disposal) ƒ Pigging programme during last months of production Cleaning is required for the removal of wax, gas dust and scale from the pipe wall. These may contain heavy metals and other toxins. This operation is achieved by driving pig trains through the line. The pig trains will include brush pigs or scraper pigs. LSA (low specific activity) scale forms in well tubulars and contains a relatively low level of radioactivity per unit mass, which however, is in excess of the background level. LSA scale is a term used in Europe; elsewhere, it may be referred to as NORM (naturally-occurring radioactive materials) scale. Note that on older pipelines with external coal tar epoxy, there is sufficient radioactivity to be detected should the coating break off and float to shore.

BRUSHPIGS