Decommissioning and abandonment

Decommissioning and abandonment

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RECOVERY BY LAYBARGE

ƒ Simpler (cheaper) than normal lay vessel ƒ J-lay does not require high tension or overbend

This method is intended for the recovery of pipelines that are either exposed on the seabed or have been unburied with specialist equipment. Either an existing laybarge or converted workbarge could be used. The J-lay approach is preferred because it requires less tension on the (possibly corroded) steel pipeline and there is no overbend on a stinger, which requires the steel to normally be taken to around 90% of yield during laying operations. Outline procedure: Deploy retrieval clamp and recovery wire to pipeline end; Recover wire through the A winch and secure pipeline with tensioners; Move barge with pipeline being recovered through tensioners; Cut pipe into pre-determined lengths and store on barge deck; Transfer pipe lengths onto supply vessel for disposal/recycling on shore or re-use after refurbishment. Advantages Utilisation of existing equipment High speed operation for long lengths Disadvantages High operating costs

CUTANDLIFT