The first line of defense is pouring drilling mud down the well . The second line is activating a blowout preventer , which for Shell Oil in the Arctic involves a double shear ram for redundancy . The third line defense is a capping stack such as was used to try to contain the Macondo Well blowout from the Deepwater Horizon oil spill of 2010 . The fourth line is the containment dome . There is experience with such technology on the BP Macondo Well in 2010 . That attempt failed ultimately because " methane gas escaping from the well would come into contact with cold sea water and form slushy hydrates , essentially clogging the cofferdam with hydrocarbon ice . " Shell Oil Company has stated via their spokesperson Kelly op de Weegh “ We are committed to having the Arctic containment system in place before drilling through liquid hydrocarbon zones , and that commitment will not change . We are nearing completion of this first-of-its-kind Arctic containment system , which houses response , containment and separation processes in one vessel . While it ’s a fourth line of defense in the unlikely event of a loss of well control , it will not be deployed until it meets our high standards . ” From the report on the Deepwater Horizon oil spill by the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling : Industry ’s responsibilities do not end with efforts to prevent blowouts like that at the Macondo well . They extend to efforts to contain any such incidents as quickly as possible and to mitigate the harm caused by spills through effective response efforts
Deepwater Horizon oil spill
Deepwater Horizon oil spill
Arctic Challenger