April 20th 2010 11 workers died and 17 were seriously injured by an explosion on the Deepwater Horizon an offshore drilling rig located approximately 50 miles off the coast of Louisiana the rig burned for two days eventually sinking and triggering the largest oil spill in US history as oil and gas spewed up from the seafloor the Deepwater Horizon had been drilling an oil well in 5,000 feet of water in an area of the Gulf of Mexico known as the Macondo prospect in 2010 the CSB launched an investigation to examine the technical organizational and regulatory factors that contributed to the accident during the investigation the CSB made new findings about why a key piece of safety equipment the deepwater horizons blowout preventer failed to seal the well during the emergency these new findings help explain why the accident was so devastating and the CSB cautioned that other blowout preventers currently in use could fail in similar ways drilling an offshore well involves creating a pathway between the drilling rig and oil and gas reservoirs trapped beneath the seafloor a deep hole or well bore is drilled through layers of subsea rock and sediment these rocky layers can contain crap water crude oil and natural gas under pressure an unplanned flow of these well fluids into the well bore known in the industry as a kick can be dangerous without careful management a kick can lead to a blowout the uncontrolled release of flammable oil and gas from the well a blowout can be catastrophic since oil and gas reaching the drilling rate can quickly find an ignition source or explosion endangering the lives of the drilling crew to prevent kicks drillers pompe dents slurry called drilling mud into the well creating a barrier between the undersea oil and gas and the piping that leads to the rig if this mud barrier fails or is somehow removed the safety of the drilling crew depends on a critical piece of equipment located on the sea floor called the blowout preventer or Bo P the Bo P is a complex electrically and hydraulically powered device that is essential for controlling the well and in an emergency situation preventing a disaster on the platform high above on the sea surface the Bo P is connected to the rig by a large diameter pipe called a riser if a kick occurs the blowout preventer is designed to prevent flammable oil and gas from traveling up the riser to the drilling rig this is done by sealing the area around the drill pipe known as the annular space to do this the crew can manually close pipe Rams and donut shaped rubber devices known as annular preventers if those devices should fail to work the last resort is a pair of sharp metal blades which form a blind shear Ram designed to cut the drill pipe and seal the well the blind shear Ram can be activated manually or by automated emergency systems at approximately 8:45 p. m. on April 20th 2010 a kick occurred in the Macondo well oil and gas entered the well bore undetected eventually passing above the blowout preventer and traveling quickly up the riser toward the Deepwater Horizon and the 126 people on just after 9:40 p.
m. drilling mud forced upwards by the rising oil and gas suddenly blew out onto the rig crew members responded by closing the upper annular preventer in the Bo P however this did not seal the well as intended and flammable oil and gas continued to flow into the riser toward the rig next the crew closed a pipe Ram this successfully closed the annular space and sealed the well but tragically this proved to be only a temporary fix oil and gas that were already above the pipe Ram continued to flow inexorably toward the Deepwater Horizon at approximately 949 p. m.
