BP Considers Resorting to "Top Kill" for Sealing Oil Leak

As BP lowers a huge coffer dam over the main oil leak, it continues mulling over other more permanent ways to stop the oil gushing from its seafloor wellhead. The "top kill" approach involves reconfiguring the blowout preventer's control box via ROV, and stuffing the well with rubber matting, followed by heavy drill muds -- provide sufficient downward pressure to overcome the upward pressure from the liquid and gaseous hydrocarbons being released.

the possible fix would use the blowout preventer that was in place when the rig exploded, burned and sank. It may have failed April 20 when a sudden burst of high-pressure hydrocarbons apparently shot from the well and up to the Deepwater Horizon, triggering a fire and explosion that killed 11 workers. The new plan is for robot submarines to remove a control mechanism from the blowout preventer and reconfigure it. Then, hoses will be inserted into existing choke and kill lines on the device. Barges on the surface will first pump what Hayward calls “junk,” or pieces of matting and rubber, into the well, followed by heavy drilling muds that should provide adequate pressure on the reservoir to close it.

The method was used to plug flaming wells in Iraq and Kuwait after the 1990-1991 Gulf War, but has not been tried at the depths of the Macondo well on which the Deepwater Horizon was working. The wellhead is under 5,000 feet of water, and the reservoir is more than two miles below that.

Relief wells proceed

Meanwhile, company officials also said they are seeing promising results from efforts to spray chemicals on the leaking oil at the seafloor to break it up and prevent it from rising to the surface. And BP continues moving forward on drilling relief wells to permanently close off the damaged one...By Wednesday morning, one rig had already reached 2,000 feet below the sea floor, and a second was preparing to begin drilling another well, Hayward said. _Chron

The oil spill is not the apocalypse:

Here are the politically incorrect truths that arm-waving anchormen and environmental activists today don’t want to face or may not be aware of:

Crude oil is a natural substance, composed of a galaxy of hydrocarbon compounds, ranging from gasoline to tar. Compared to infinitely more toxic refined oil products like Diesel fuel, it is unstable and tends to disintegrate into volatile compounds.

Much of it will evaporate, given the right conditions.

What won’t evaporate will be attacked by oil-eating microbes in the sea water.

The degree of evaporation and the success of the microbe attack will depend upon several factors:
The chemistry of the crude oil in question.
The temperature of the air and of the water.
The dynamic action of sun, wind and waves at the spill site.

...The BP spill is unquestionably a calamity. There will be enormous costs, including costs to fish and wildlife interests. There will be some wetlands damage. But many of the same factors that ameliorated the Tobago spill are at work off the mouth of the Mississippi. Strong southeast winds have been spreading the spill and encouraging its evaporation. Air temperatures in the 80s water temperatures in the 70s and plenty of sun have encouraged the attack of oil-eating microbes.

All that has reached shore at this writing has been a thin sheen, comparable to what one sees in parking lot puddles after a rain. The winds have now shifted to move the slick toward Mississippi, Alabama and Florida. But as it moves, it thins further, and all those meteorological dynamics favoring breakdown are at work. We can only hope that they continue. The chemistry of oil from each well drilled in the Gulf of Mexico is a little different, but basically we can say the oil from the BP spill ranks somewhere in viscosity between the tarry crudes of Alaska and the western US and the light Arabian crude spilled at Tobago.

What will happen when it hits the Gulf Coast wetlands? Most fish and birds will avoid the area. Obviously larval oysters, crabs and other estuarine creatures will suffer. But oil has been drilled from, pumped across and spilled on Gulf Coast wetlands for more than half a century. The wetlands eventually recover, because nature bats last. _NiemanWatchdog