Small-scale technology tests by the U.S. and Japan in the North Slope of Alaska have extracted a steady flow of natural gas from methane hydrates, the U.S. Department of Energy (DOE) said on Wednesday. If new research efforts to conduct long-term production tests in the Arctic and Gulf Coast are successful, they could unlock a “vast, entirely untapped resource” that would hold significant enormous potential for U.S. energy security, the agency said.
Methane hydrates are 3D ice-lattice structures with natural gas locked inside, found both onshore and offshore—including under the Arctic permafrost and in ocean sediments along nearly every continental shelf in the world. “The substance looks remarkably like white ice, but it does not behave like ice,” the DOE said. When methane hydrate is “melted,” or exposed to pressure and temperature conditions outside those where it is stable, the solid crystalline lattice turns to liquid water, and the enclosed methane molecules are released as gas.
The agency partnered with ConocoPhillips and the Japan Oil, Gas and Metals National Corporation to conduct a test of natural gas extraction from methane hydrate using a production technology developed through laboratory collaboration between the University of Bergen, Norway, and ConocoPhillips. The ongoing proof-of-concept test began on Feb. 15, 2012, and concluded on April 10.
The team injected a mixture of carbon dioxide (CO2) and nitrogen into the formation, and demonstrated that this mixture could promote the production of natural gas. Ongoing analyses of the extensive datasets acquired at the field site will be needed to determine the efficiency of simultaneous CO2 storage in the reservoirs, the DOE said.
This test was the first ever field trial of a methane hydrate production methodology whereby CO2 was exchanged in situ with the methane molecules within a methane hydrate structure. As part of this exchange demonstration, the depressurization (i.e., production through decreasing pressure of the deposit) phase of the test extended for 30 days. The prior longest-duration field test of methane hydrate extraction via depressurization was six days (Japan-Canada 2007/2008 Mallik well testing program).
“This testing will provide critical information to advance the Department’s efforts to evaluate various potential gas hydrate production technologies,” the DOE said. “The next stages of the Department’s research effort will be aimed in part at evaluating gas hydrate production over longer durations, likely through depressurization, with the eventual goal of making sustained production economically viable.”
While this may take years to accomplish, “the same could be said of the early shale gas research and technology demonstration efforts that the Department backed in the 1970s and 1980s,” the agency said.
“The Energy Department’s long term investments in shale gas research during the 70s and 80s helped pave the way for today’s boom in domestic natural gas production that is projected to cut the cost of natural gas by 30 percent by 2025 while creating thousands of American jobs,” said Secretary Chu. “While this is just the beginning, this research could potentially yield significant new supplies of natural gas.”
On Wednesday, the DOE announced two major new steps in the overall methane hydrate research effort. First, it will make $6.5 million available in a Fiscal Year 2012 Funding Opportunity Announcement for research into technologies to locate, characterize and safely extract natural gas from methane hydrate formations like those in the Arctic and along the U.S. Gulf Coast. Projects will address deepwater gas hydrate characterization via direct sampling and/or remote sensing field programs; new tools and methods for monitoring, collecting, and analyzing data to determine reservoir response and environmental impacts related to methane hydrate production; and clarifying methane hydrates role in the environment, including responses to warming climates.
As part of the Obama administration’s proposal for Fiscal Year 2013, the DOE will also request an additional $5 million to further gas hydrates research both domestically, and in collaboration with international partners. “The exact nature of that research effort will be determined in the coming months; however, a longer duration test of methane hydrate extraction on the North Slope on an existing gravel bed pad that can accommodate year-round operations is envisioned. Such an effort would again require engaging private sector and international partners,” it said.
Sources: POWERnews, POWER, DOE