In September 2007 it established subsidiary MOEX Offshore 2007 LLC which entered into a partnership with BP for drilling in the Gulf of Mexico . On April 20 , 2010 , its rig the '' Deepwater Horizon '' exploded and sank , causing a massive oil spill . In May , 2011 , MOEX Offshore , having had a 10 % stake in the Deepwater Horizon through a subsidiary , agreed to pay US$ 1.07 billion to settle BP claims against it over the accident . Some analysts had thought BP would realize a larger settlement from MOEX but there was also relief to have a first step toward resolving the multiple claims
oil spill
Deepwater Horizon oil spill
Mitsui Oil Exploration