Just days before the explosion aboard the Deepwater Horizon oil rig, the rig’s crew received a memo from Transocean Ltd, the owner of the platform, warning them not to be “complacent” about well control. According to a report in The Wall Street Journal, the memo was prompted by an incident on a Transocean rig in Britain’s North Sea in December of the previous year.
According to the Journal, the crew aboard that rig – Sedco 711 – heard a loud noise just before dark liquid started shooting out of the well. Explosive gas began to surround the rig, and crews began to prepare for an evacuation. Fortunately, they were able to bring the well under control before anything catastrophic happened.
Transocean officials were so disturbed by the incident that they held conference calls with all managers aboard their 170 offshore rigs and issued two safety memos, the Journal said. They concluded that the crew of Sedco 711 had put too much faith in tests that showed the well was secure and stopped watching for signs of trouble. “The drill crew did not consider [a loss of] well control as a realistic event,” because of a successful valve test, Transocean wrote in an April 14 memo.
According to the Wall Street Journal, the investigation into the April 20 Deepwater Horizon explosion has suggested that crews on that Gulf of Mexico rig also relied to much on such tests, and missed important warnings that something was amiss with the well. Prior to the both the Sedco 711 incident and the Deepwater Horizon explosion, workers had been removing heavy mud from the wells, and both had been sealed off with cement. In each case, crews had run a series of tests that they believed showed the wells were secure, the Journal said.
The Journal also points out that in both cases, workers were pumping fluid into and out of the well in a way that made it difficult to monitor volumes precisely. An increase in fluid flowing out of a well is a critical sign that gas is forcing its way in. Federal investigators have identified the way workers pumped fluid on the Deepwater Horizon as one of 20 “anomalies” that may have contributed to the disaster, the Journal said.
In other news, some scientists are criticizing a government report claiming that nearly 75 percent of the oil released as a result of the BP oil spill has already disappeared. According to government estimates, 4.9 million barrels of oil escaped from the well between the April 20 explosion aboard the Deepwater Horizon oil rig and the deployment of a containment cap that finally stopped the flow on July 15. Earlier this month, a scientific team led by the National Oceanic and Atmospheric Administration released a report purporting that most of the oil had been captured, burned off, evaporated or broken down in the Gulf.
Now, researchers from the University of Georgia are calling that figure “inaccurate,” saying nearly 79% of the oil still remains in the Gulf of Mexico in some form. According to The Wall Street Journal, the University of Georgia research team has been investigating the underwater oil plumes created by the leaking well.
“One major misconception is that oil that has dissolved into water is gone and, therefore, harmless,” marine scientist Charles Hopkinson, the senior investigator in the effort, told the Journal. “The oil is still out there, and it will likely take years to completely degrade.
A second research team from the University of South Florida said dispersants used to break up the massive spill has pushed much of the oil to the bottom of the sea.
“The dispersant is moving the oil down out of the surface and into the deeper waters, where it can affect phytoplankton and other marine life,” John Paul, a USF marine microbiologist told CNN.
According to the CNN report, the USF researchers also believe oil may have settled to the bottom of the Gulf of Mexico further east than previously suspected. Some of it has turned up at the bottom of an undersea canyon within 40 miles of the Florida Panhandle.