Gas from Hydrate Production within a Decade
by F. Jay Schempf
|Friday, August 01, 2003
Abstract: Don't look now, but capturing and using "the ice that burns" is a lot closer to reality than most people might think.
Analysis: Actual production of U.S. methane (gas) hydrates could begin within a decade, U.S. Interior Secretary Gale Norton said publicly a few weeks ago when speaking to a gathering of natural gas industry executives in Washington DC.
A rather innocuous statement, until you consider two points:
Of course, the federal government has been involved in methane hydrates ("hydrates") research for nearly two decades. In fact, various federal agencies started investigating them as far back as the late 1980s, long before private industry openly considered them a serious potential energy source. The DOI, DOE, U.S. Navy, National Science Foundation, and a passel of other government and quasi-government organizations were among the first to seize on hydrates as an R&D quarry worthy of pursuit. The academic community gladly joined the group, as well, and literally scores of colleges and universities have striven to corner various facets of hydrates R&D as their specialty.
But for obvious reasons, the petroleum industry treated naturally occurring gas hydrates--those formed by nature beneath permafrost in Arctic climes and in deepwater offshore--mostly as a subject of purely scientific interest. However, "artificial" hydrates, which can form inside pipe when temperatures and pressures hit the right combination, can and do form frozen plugs, particularly offshore. These plugs pose a considerable added expense to oil and gas companies operating offshore, particularly if production is interrupted and unplugging operations become necessary. In fact, preventing hydrate plugs from fouling undersea gathering systems, wellhead equipment, and even downhole tubulars is a major focus of flow assurance, a crucial new specialty in offshore operations these days, particularly as sea-bottom equipment is placed in deeper water with lower temperatures and higher pressures.
However, three or four years ago, when hints of a slackening in conventional domestic natural gas supply began to surface, the industry started looking more closely at hydrates from the fuel source angle. Today, with gas demand overtaking supply an apparent reality; industry focus on hydrates is even sharper. For instance, the Canadian government and Japanese companies drilled several hydrates core holes in Canada's McKenzie Delta area in 2001, and are slowly revealing their findings at various scientific gatherings. Canada's Arctic area holds huge hydrates accumulations, and it's no secret that the Japanese see the undersea hydrates around the home islands as a potential source of their own energy, as opposed to depending almost totally on imports.
Also, as recorded here previously, both BP and Anadarko Petroleum have drilled an onshore hydrates test well, the Hot Ice No. 1, on Alaska's North Slope and plan further testing on that well this winter, followed by additional test wells. Combined with investment by BP/Anadarko and Noble Corp.'s Maurer Technologies Inc., the Department of Energy (DOE) is contributing taxpayer dollars to the Hot Ice Project, as it's called (see "North Slope Methane Hydrates Coring Starts Soon," Rigzone.com, March 3, 2003).
Obviously, producing methane from Arctic onshore hydrates deposits probably is what Secretary Norton was referring to in her allusion to a foreshortened time estimate to actual production. However, the largest hydrates concentrations exist beneath the deep ocean floor. Probably many of us have read the almost fantastic estimates of the sheer methane volumes contained in U.S. subsea hydrates deposits--enough gas in one bed off the Carolinas, for example, to power the nation for 50 years.
In addition to purely scientific offshore hydrates research ventures (a total of 15 separate hydrates-related research cruises were planned for U.S. waters alone in 2003), more industry/government/academia joint projects also are underway. For instance, a Joint Industry Project (JIP), involving the DOE, a number of major U.S., Japanese, and Indian companies, joined by several petroleum service providers and a group of colleges and oceanographic institutions, is working toward characterizing deepwater Gulf of Mexico hydrates as well as coming up with applications for eventual safe hydrates exploration and production activities in the Gulf. The JIP was formed in September 2001 with ChevronTexaco as operator.
The project (DOE identifies it as DE-FC26-01NT41330), with an estimated cost of US$13.6 million, is well on track toward completion in the first quarter of 2005. Technical teams have collected data on deep GOM hydrates, including design of geoscience/reservoir and wellbore stability models, and the venture already has contracted for a coring vessel to drill three test wells in two separate areas of the deepwater Gulf, with drilling scheduled to start next April.
Helping to establish how GOM hydrates act as a trapping mechanism for shallow oil and gas reservoirs in deepwater and how that might affect eventual production of Gulf hydrates is but one goal of the JIP. The primary objective is to provide better understanding of how natural hydrates can affect sea floor stability. In so doing, the coring should provide data to be used by scientists in their studies of climate change. That's because, based on good paleoceanographic evidence gained by scientific research involving cores taken during Ocean Drilling Program cruises, among others, scientists hypothesize today that in the geological past, releases of large volumes of methane from undersea hydrates during periods of ocean temperature rises have caused dramatic climate changes. Methane is, after all, a potent greenhouse gas. The idea's still hypothetical, but even the Antarctic ice cap reveals high concentrations of carbon that coincide with atmospheric changes known to have occurred around the world during past ages, even as late as several hundred years ago. Some even go so far as to attribute the Dark Ages at least in part to the effects of heavy releases of methane from hydrates into the ionosphere, which apparently partially blocked the sun's rays, nearly ending life on the planet.
And, of course, there's the way-out theory that the infamous Bermuda Triangle is really an area in which methane often dissociates from hydrates' icy jackets, challenging vessel buoyancy on the water's surface and the combustion of fuel in aircraft engines as it rises through the atmosphere.
But from a more practical viewpoint, another viable goal of such research projects is to determine what effects methane dissociation from shallow hydrates deposits have on fixed and floating offshore hardware. That includes mobile drilling rigs, fixed and floating production facilities, and sea floor equipment of all kinds. Take it even further: It involves nearly everything that floats.
Oil companies don't mention it much, but naturally occurring hydrates in the Gulf have affected such equipment, though it's generally believed that nothing catastrophic has yet occurred. However, hydrates dissociation due to heat generated by drilling often causes well "kicks" which, if not muffled soon enough, can result in well blowouts.
And one need only imagine what might happen to subsea equipment resting on the ocean floor were massive subsidence to occur as a result of dissociation of a shallow hydrates bed and the release of any conventional gas that might have been trapped beneath it. What's more, mudslides related to such dissociation also are known to have occurred--and apparently still do--worldwide, both on the edges of the outer continental shelf and even on the abyssal plain. What might happen to a fixed production platform or pipeline were it to lie in the path of such a slide? The petroleum industry is taking such questions very seriously in light of their rapid push into deeper water. The government is, too. But so far, the last two U.S. Presidents have kept capital appropriations for hydrates research at rock bottom. Odd, given the interest shown by DOE, DOI, and other such bodies, as well as hydrates' growing importance to industry.
So, regardless of their immediate import to commerce, methane hydrates and their future as an energy source, as well as the potential threat they pose to world climate and to offshore equipment, will continue to be discussed here from time to time.
They've arrived, officially.