first_img KCS-content AT A GLANCE | BP’S COUNTDOWN TO THE GULF OIL SPILL whatsapp whatsapp Share More From Our Partners Russell Wilson, AOC among many voicing support for Naomi Osakacbsnews.comBrave 7-Year-old Boy Swims an Hour to Rescue His Dad and Little Sistergoodnewsnetwork.orgKiller drone ‘hunted down a human target’ without being told tonypost.comNative American Tribe Gets Back Sacred Island Taken 160 Years Agogoodnewsnetwork.orgFlorida woman allegedly crashes children’s birthday party, rapes teennypost.comA ProPublica investigation has caused outrage in the U.S. this weekvaluewalk.comMark Eaton, former NBA All-Star, dead at 64nypost.comPolice Capture Elusive Tiger Poacher After 20 Years of Pursuing the Huntergoodnewsnetwork.orgAstounding Fossil Discovery in California After Man Looks Closelygoodnewsnetwork.org Weak cement workThe day before the accident, cement was pumped down a pipe in the well, which squeezed back up the space between the pipe and the rock layers, known as the annulus. That “light, nitrified foam cement slurry” failed to block oil and gas from moving up into the annulus. Cement design, testing, quality assurance and risk assessment was weak.Barriers failedOnce oil and gas got into the annulus, “shoe track barriers” failed to prevent hydrocarbons from entering the pipe. A shoe track is a barrier designed to block hydrocarbons from entering the bottom of the pipe.Pressure tests misreadA negative pressure test performed on the day of the explosion was misinterpreted as successful by BP well site leaders and the Transocean rig crew. Pressure readings really indicated that hydrocarbons were flowing into the well from the reservoir, but were interpreted as showing that oil and gas were blocked by barriers provided by the cement, shoe track, casing and a casing seal.Delay in detectionThe breach of oil and gas into the well wasn’t detected until they had reached the riser, a pipe that connected the well to the rig.Failure to regain controlEfforts to bring the well under control failed. Crews first tried to close a blowout preventer at the seabed and a diverter, but oil and gas shot up the riser. Hydrocarbons went to an onboard system that separated drilling mud from natural gas rather than to an overboard diverter line that would have sent them into the sea.Separator overwhelmedFast incoming oil and gas overwhelmed the mud gas separator, allowing gas to be vented onto the rig.Air con propelled the gasThe Horizon’s heating, ventilation and air conditioning system likely moved the gas to engine rooms where ignition risk was high.Blowout preventer failedThe blowout preventer failed to seal the well. The report said the explosions and fire on the rig likely disabled mechanisms that allowed rig crews to seal the well and disconnect the riser. In addition, control pods on the blowout preventer were faulty, and underwater robots failed to manually activate valves in it as oil spewed into the ocean after the disaster. Show Comments ▼ Wednesday 8 September 2010 8:31 pm Tags: NULLlast_img

AT A GLANCE | BP’S COUNTDOWN TO THE GULF OIL SPILL

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