The vast deepwater methane hydrate deposits of the Gulf of Mexico are an open secret in big energy circles. They represent the most tantalizing new frontier of unconventional energy — a potential source of hydrocarbon fuel thought to be twice as large as all the petroleum deposits ever known.
For the oil and gas industry, the substances are also known to be the primary hazard when drilling for deepwater oil.
Methane hydrates are volatile compounds — natural gas compressed into molecular cages of ice. They are stable in the extreme cold and crushing weight of deepwater, but are extremely dangerous when they build up inside the drill column of a well. If destabilized by heat or a decrease in pressure, methane hydrates can quickly expand to 164 times their volume.
Survivors of the BP rig explosion that right before the April 20 blast, workers had decreased the pressure in the drill column and applied heat to set the cement seal around the wellhead. Then a quickly expanding bubble of methane gas shot up the drill column before exploding on the platform on the ocean's surface.
Even a hardened steel pipe has little chance against a 164-fold expansion of volume — something that would render a man six feet six inches tall suddenly the height of the Eiffel Tower.
Scientists are well aware of the awesome power of these strange hydrocarbons. A sudden large scale release of methane hydrates is believed to have caused a mass extinction 55 million years ago. Among planners concerned with mega-disasters, their sudden escape is considered to be a threat comparable to an asteroid strike or nuclear war. The Lawrence Livermore National Laboratory, a Livermore, Ca.-based weapons design center, that when released on a large scale, methane hydrates can even cause tsunamis.
So it is not surprising to anyone who knows about the physics of these compounds that the Deepwater Horizon rig was lost like a waterfly crumpled by a force of nature scientists are still just getting to know.
Number One Deepwater Drilling Issue
SolveClimate contacted scientists at the who focus on the fundamental science and engineering of methane hydrates to gain further insight. They did not want to speculate on the role that methane hydrates could have played in the BP disaster, but they were willing to provide a basic understanding of the nature and behavior of these familiar but little understood substances.
"Gas hydrates are the number one flow assurance issue in deepwater drilling," Carolyn Koh, an associate professor and co-director of the Hydrate Center, told us in an exclusive interview.
She explained that the oil and gas industry has a lot of experience with methane hydrates, because they have to be kept from forming in pipes or they will clog the lines, stop the flow of oil, and pose a danger. Drillers use inhibitors such as methanol to keep the hydrates from crystallizing inside drill rigs operating at great depth, where conditions for methane hydrate formation are ideal.
This of an experiment conducted on the ocean floor near the Deepwater Horizon drilling site demonstrates how quickly and easily methane hydrates can form. It was conducted by the aboard the Seward Johnson in September 2006. The voices of the scientists conducting the experiment are clearly audible.