Decommissioning Cost Estimation in the Deepwater U.S. Gulf of Mexico

Abstract

Deepwater structures are expensive to fabricate and install, and at the end of their useful life, will also be expensive to decommission. From 1989 to 2012, 15 structures in water depth greater than 400 ft were decommissioned in the U.S. Gulf of Mexico. The purpose of this chapter is to estimate cost for well plugging and abandonment, conductor severance and removal, pipeline abandonment, umbilical and flowline removal, and platform removal for the 95 deepwater structures (50 fixed platforms, 3 compliant towers, and 42 floaters) in the Gulf of Mexico circa January 2013. Work decomposition algorithms developed by ProServe Offshore are combined with government databases and the author's generalizations to provide order-of-magnitude cost estimates for the deepwater structure inventory. Bullwinkle and Pompano are expected to be the most expensive fixed platform decommissioning projects estimated at $265 million and $203 million, respectively. Mars is expected to be the most expensive floater decommissioning at a cost of $336 million, followed by Ursa ($222 million), Auger ($205 million), and Hoover/Diana ($201 million). Total decommissioning liability for the deepwater structure inventory based on 2009–2010 market conditions and technologies and the collection of assumptions described herein, is estimated at $6.7 billion, $2.4 billion for fixed platforms and compliant towers, and $4.3 billion for floaters.