Natural gas from ruptured Gulf well remained trapped in deep waters

By PAUL VOOSEN of Greenwire
September 17, 2010 Perhaps it should have been called the Gulf of Mexico gas spill. A vast majority of the natural gas that billowed out of BP PLC’s failed well in the Gulf this summer did not escape to the surface and atmosphere. Instead, the gas — including its main component, methane — remained trapped deep underwater, priming the bacterial response to the spill, according to research published online yesterday in Science. Oil has long been the most visible component of the hydrocarbon rush that gripped the Gulf this summer, even when invisible, in the form of underwater mists of oiled water. Natural gas, billowing out from the Macondo well alongside oil at double the amount, often received scant attention from the public, press and government. Fortunately, scientists were not so easily fixated on the crude. In June, while the well resisted control, scientists led by David Valentine, a microbial geochemist at the University of California, Santa Barbara, took several hundred samples of natural gas at 31 sites in a large circle around Macondo, extending to a maximum of 8 miles from the spill’s epicenter. Data from their cruise, sponsored by a grant from the National Science Foundation, amount to the first independent snapshot of the immediate, short-term response triggered underwater by an onslaught of gas. The majority of the methane, they found, remained dissolved more than 2,600 feet underwater, and the gas likely accounted for two-thirds of all the microbial activity in the undersea plumes. Based on government and BP data, some 206,000 metric tons of methane, 35,700 tons of ethane and 28,400 tons of propane snaked out into the subsurface, they estimated. “The concentrations in the deep plumes were typically more than 500 times the concentrations in the shallower water,” Valentine said. “This is good evidence that the majority of methane was trapped and is consistent with most other works on the matter.” …

Natural Gas From Ruptured Gulf Well Remained Trapped in Deep Waters