Decommissioning Thailand

Laytrix undertook a desktop feasibility study for an American oil major working in Thailand who were tasked with the decommissioning of a large number of rigid pipelines which had reached the end of their working lives and were no longer operational.

The desktop study compared the use of the Laytrix decommissioning system with their initially preferred “cut & grab” method where the pipeline was cut into sections on the seabed and then recoveed to a vessel. In addition to this a third option of using an S-lay vessel and a reverse recovery process was also considered.

For the project a range of diameters from 2.5” to 15” was considered along with a total length of approximately 400 Km. Whilst the S-lay spread was able to recovery the product in a quicker timescales the costs associated with the more expensive vessel day rates led to large overall project costs with the use of the Laytrix spread leading to costs in the region of 45% of those of the S-lay approach.

A comparison to their preferred method showed it was both slower and more costly than the use of the Laytrix system. The Laytrix system all led to the lowest amount of emissions based on a CO2 equivalent due to the use of a smaller more efficient vessel, lower line tensions and hence a reduction in bollard pull when compared to S-lay and the more efficient process and shorter vessel time when compared to the cut and grab recovery using a similar vessel.