remote-control acoustic switches
*** First, a pretty good 2 minute recap of where we're at, from ABC News
Wall Street Journal article
The oil well spewing crude into the Gulf of Mexico didn't have a
remote-control shut-off switch used in two other major oil-
producing nations as last-resort protection against underwater
The lack of the device, called an acoustic switch, could amplify
concerns over the environmental impact of offshore drilling after
the explosion and sinking of the Deepwater Horizon rig last
Nevertheless, regulators in two major oil-producing countries,
Norway and Brazil, in effect require them. Norway has had acoustic
triggers on almost every offshore rig since 1993.
The U.S. considered requiring a remote-controlled shut-off
mechanism several years ago, but drilling companies questioned its
cost and effectiveness, according to the agency overseeing offshore
drilling. The agency, the Interior Department's Minerals Management
Service, says it decided the remote device wasn't needed because
rigs had other back-up plans to cut off a well.
.... As a third line of defense, some rigs have the acoustic
trigger: It's a football-sized remote control that uses sound waves
to communicate with the valve on the seabed floor and close it.
An acoustic trigger costs about $500,000, industry officials said.
The Deepwater Horizon had a replacement cost of about $560 million,
and BP says it is spending $6 million a day to battle the oil
spill. On Wednesday, crews set fire to part of the oil spill in an
attempt to limit environmental damage.