Decommissioning of a tension leg platform – possible removal options for a challenging project in the Gulf of Mexico

The Decommissioning is a “multidisciplinary” process by which an Oil Company goes through of deciding how best shut down the oilfield activities at the end of the field life, plugging and abandoning the well(s), making the equipment/installation safe, remove some or all the facilities (offshore structures and appurtenances e.g.: platforms, top sides, jackets etc.) and restoring the area. Decommissioning will occur at different stages of asset lifecycle and has wide relevance in terms of reputation, so it needs to be managed properly as a dedicated business process. Usually Oil Companies decommissioning approach is based on international Waste Hierarchy Policy (Picture 1): in other words the conceptual framework which ranks the options for dealing with waste, beginning from the reducing of their generation, listing in order of preferences, the possible approaches/actions for their management: so, re-use of the decommissioned facilities is a preferred choice to recycle and re-use in current location is preferred to re-use in new location; recycle of the decommissioned facilities is a preferred choice to disposal.