Rubber gaskets failed on Gulf well blowout preventer
Image via WikipediaHouston Chronicle:
Blind shear rams on the Deepwater Horizon’s blowout preventer successfully closed when the drilling rig disconnected from the well, but the flow of oil blasted through rubber gaskets around the rams, according to sources familiar with an investigation of the device.It looks like the engineers are going to have to tweak their calculations on the amount and type of rubber to be used in the gaskets for blowout preventers in deep water wells. They may also have to look at the design of the shear ram as well as adding additional shear rams to the system. The pressure should be reduced at the level of the additional rams and gaskets.
The BOP has been the subject of forensic examination since it was raised from the seafloor last year and transported to a NASA facility outside of New Orleans. Investigators are trying to determine why the device, which is supposed to seal off the well in an emergency, continued to let oil flow, leading to one of the nation’s largest environmental disasters.
Sources say investigators have determined that the BOP’s ‘dead man’ function did work when the rig made an emergency disconnect from the well, activating a set of dual-blade rams that cut through pipe in the well and sealed it off.
However, the force of oil and gas flowing through the well appears to have been too strong to be contained by rubber gaskets – known as packers – around the edges of the blades. The packers were essentially blown away, allowing oil to flow around the closed shear ram blades.