As Oil & Gas fields reach the end of their lifespan, they must be decommissioned. This complex task involves a number of highly skilled workers to ensure that the wells and platforms are safely and efficiently dismantled and removed. With a huge number of offshore rigs expected to reach the end of their production cycle over the next ten years, the global need for technical decommissioning specialists is expected to grow, with annual spending projected to reach $13 billion within the next 25 years.
To prepare you for the rapid expansion of this part of the industry, here’s everything you need to know about offshore decommissioning.
WHAT IS DECOMMISSIONING?
Decommissioning is the term used to describe the final stage of an energy project. In oil and gas, when a field production cycle comes to an end and all the usable fuel has been processed, the facilities must be dismantled and the surrounding area returned to its natural condition. This is a legal condition as set out by the Petroleum Act 1998.
The process involves clearing and filling the well, and removing the infrastructure and platform. In some cases, certain parts of the conductor pipes can be left in place to form artificial reefs for ocean life, but most are fully cleared to ensure minimal environmental impact.
WHAT DOES DECOMMISSIONING AN OFFSHORE OIL PLATFORM ENTAIL?
Decommissioning is a long and complex process. It’s a massive engineering task that requires almost as many workers as it takes to man a fully operating platform. The platform must be cleared of all equipment, the well plugged and all elements of the infrastructure removed from the seabed.
Oil and gas production platforms span the entire water column from the seafloor through the sea surface like an island. However, distinct from an island, the openness of a petroleum structure allows for water circulation, oceanic energy dissipation, and easy mobility for fishes inside the structure.
For decommissioning purposes, platforms generally consist of two distinct parts: the topside (the facilities visible above the waterline) and the substructure (the parts between the sea surface and the seabed, or mudline). During decommissioning, topside facilities that contain the operational components are completely removed and taken to shore for recycling or partial re-use. The substructure supporting jacket is generally severed 15 feet below the mudline, then pulled out of the seafloor, removed, and barged to shore to sell as scrap for recycling or refurbished for installation at another location with some part(s) ending up in a landfill.