Denmark’s Maersk Drilling and Norway’s Seadrill are understood to have been picked by US oil company Anadarko to compete to provide it with a high-end newbuild drillship featuring a 20,000-psi blowout preventer for long-term work in the Gulf of Mexico.

Maersk and Seadrill were part of a list of five that originally also included Transocean, Noble Drilling and Rowan, sources said, adding that some of those that have fallen out of the race for the five-to-seven-year contract were now seeking explanations about why they did not make it onto the shortlist.

However,