The design of the '' Q4000 '' includes the following features : '' Q4000 '' was in the Gulf of Mexico participating in the response to the Deepwater Horizon oil spill . The vessel was used to position the large containment dome and also to attempt the " top kill " in which large quantities of drilling mud were pumped down the '' Q4000 '' drilling pipe into the failed '' Deepwater Horizon '' blowout preventer valve ( BOP ) in an attempt to stop the flow of oil . Both attempts failed to stop the oil leaking from the well . After removal of the failed riser and drill pipe on the Horizon BOP , a capping stack sealed the top of the well on July 15 , 2010 , stopping the flow of oil into the Gulf of Mexico . The '' Q4000 '' was used in a successful static kill procedure , where mud , followed by cement , was pumped into the well , sealing the leak at the source . The '' Deepwater Horizon '' BOP was secured on the deck of the '' Q4000 '' around 10:20 pm on September 4 , 2010 . The failed '' Deepwater Horizon '' BOP was collected as key evidence into the investigation of the causes of the oil spill
Deepwater Horizon oil spill
Deepwater Horizon oil spill
Q4000