Decommissioning and abandonment

Decommissioning and abandonment

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Decommissioning in-situ is often the preferred method for trunk lines and pipelines that are already buried or trenched. To decommission in-situ, it will be necessary to ensure that all product is removed from the pipeline and the pipeline interior cleaned of debris and harmful deposits. Cleaning can be done with specialist cleaning pigs and batches of cleaning chemicals during the final months of producing. The final removal of the product itself is done with pig trains, pushed through by water. There may be a requirement that the decommissioned pipeline is buried to ensure it does not become a future obstacle on the seabed. It may be necessary to ensure the strength of pipe is sufficient to withstand the trenching operation. Care should also be taken to ensure the concrete coating does not break-up and become debris on the seabed.