Decommissioning cost estimation for deepwater floating structures in the US Gulf of Mexico

Floating structures are expensive to fabricate and install, and, at the end of their useful life, will also be expensive to decommission. Industry experience decommissioning deepwater structures in the Gulf of Mexico is extremely limited, and to date, only four floating platforms in water deeper than 1000 ft have been removed from service. The purpose of this paper is to apply work decomposition algorithms developed by ProServ Offshore to estimate the cost for well plugging and abandonment, pipeline decommissioning, umbilical and flowline removal, and deck and hull removal for the 42 floating structures that reside in the Gulf of Mexico circa 2013. Mars is expected to have the largest decommissioning exposure at $336 million, followed by Ursa ($222 million), Auger ($205 million), and Hoover/Diana ($201 million). Nineteen structures are expected to have decommissioning cost exceeding $100 million. Total undiscounted decommissioning cost for the 2013 floater inventory is estimated at $4.3 billion. Deepwater decommissioning cost estimates will change with changing technologies, regulations and market conditions.