The pace of gas hydrate energy assessment projects has accelerated over the past year, with a series of planned field tests in 2004 that may help prove the viability of gas hydrates as a commercial resource.
Gas hydrate is an ice-like substance that forms when gas and water combine under conditions of relatively high pressure and low temperature. Gas-hydrate-bearing sediments are widespread in marine environments beneath continental margins and in permafrost regions, and are known to contain significant amounts of natural gas.
Researchers have long speculated that gas hydrates could eventually be a commercial resource, but technical and economic hurdles historically have made gas hydrate development a distant goal rather than a near-term possibility.
Changing Perspectives
This view began to change over the past five years with the realization that this unconventional resource could be developed in conjunction with conventional fields. Research coring and seismic programs carried out by the Ocean Drilling Program (ODP), government agencies and several consortia have significantly improved our understanding of how gas hydrates occur in nature -- and have verified the existence of highly concentrated gas hydrate accumulations at several locations.
The most significant development was the production testing conducted at the Mallik site in Canada's Mackenzie Delta in 2002 (EXPLORER, January 2003). The test was conducted by an international consortium led by the Geological Survey of Canada and the Japan National Oil Company.
Results of the test will be made public at a Dec. 8-10 symposium in Chiba, Japan (http://www.mh21japan.gr.jp). While details of the test are not yet public, the consortium has confirmed that gas was produced from gas hydrates.
Data acquired at Mallik is being used to model the potential production characteristics of gas-hydrate-bearing reservoirs at several other locations.
In the summer of 2002, ODP Leg 204 investigated the formation and occurrence of gas hydrates in marine sediments at Hydrate Ridge off the Oregon coast. The shipboard scientists successfully deployed new core systems for recovering and analyzing gas-hydrate-bearing sediments at in situ pressure conditions -- thus allowing the correlation of sediment properties with seismic, conventional wireline and LWD logging data.
The outlook for gas hydrates as a resource has been improved by higher natural gas prices and forecasts of future tighter supply. Unconventional gas resources can play an important role in meeting our future demand as long as they can be economically produced.
Several gas hydrate researchers have pointed to coalbed methane (CBM) as a model for gas hydrates: Twenty years ago CBM was widely dismissed as uneconomical, but today it represents 8 percent of domestic gas production.
Current U.S. Gas Hydrate Programs
In the United States, the Department of Energy (DOE), in cooperation with the U.S. Geological Survey and other agencies, coordinates gas hydrate research activities. The DOE lead program funds laboratory and field research on both arctic and marine gas hydrates.
Additional program information may be obtained at the DOE Web site http://www.fe.doe.gov/programs/oilgas/hydrates/.
Current Arctic studies include:
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A three-year program sponsored by Maurer Technology and Anadarko Petroleum, in partnership with the DOE. Anadarko spudded the "Hot Ice 1" well on the North Slope of Alaska in March 2003.
Hot Ice 1 was designed to validate geological, geophysical and geochemical models of arctic gas hydrate occurrences. The well was suspended in April and operations are scheduled to resume this winter. See the Maurer Web site http://www.maurertechnology.com/.
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BP Exploration (Alaska) and the DOE also have undertaken a project to characterize, quantify and determine the commercial viability of gas hydrates and associated free gas resources in the Prudhoe Bay, Kuparuk River and Milne Point field areas in northern Alaska. The University of Alaska in Fairbanks, the University of Arizona in Tucson and the USGS also are participating in the Alaska BP project.
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Several Gulf of Mexico programs are currently under way. The most comprehensive study is a Joint Industry Project (JIP) led by ChevronTexaco, designed to further characterize gas hydrates in the Gulf of Mexico. Participants include ConocoPhillips, Total, Schlumberger, Halliburton Energy Services, U.S. Minerals Management Service (MMS), Japan National Oil Corp. and India's Reliance Industries.
The JIP is planning to drill and core multiple GOM sites in 2004.
While the primary goal of this JIP is to better understand the safety issues related to gas hydrates, the results of the program also will allow a better assessment of the commercial potential of marine gas hydrates.
In anticipation of gas hydrate production in federal waters, the MMS has recently launched a project to assess gas hydrate energy resource potential on acreage under MMS jurisdiction.
International Programs
In 1995, the government of Japan established the first large-scale national gas hydrate research program, which now plays a leading role in worldwide gas hydrate research efforts. Plans for 2004 include drilling and coring between 10 and 20 wells in the Nankai Trough off Japan's East Coast, where gas hydrates were recovered during previous field studies in 2000.
Japan has budgeted more than $65 million (US) for next year's gas hydrate studies.
The government of India also is funding a large national gas hydrate program to meet their growing gas requirements. Seismic data have been acquired on the Indian continental margin, and current plans call for drilling and coring dedicated gas hydrate wells in 2004.
In addition, gas hydrates were recently discovered during drilling for conventional oil and gas resources in the Krishna-Godavari Basin.
AAPG/EMD Involvement
EMD's Gas Hydrate Research Committee was established in 1999 to promote gas hydrate research and development by bringing industry, government and university researchers together in order to exchange information and ideas.
At this past year's AAPG Annual Meeting in Salt Lake City the committee solicited volunteers as members of a Gas Hydrate Energy Resources Working Group. This group plans to develop a formal position statement on gas hydrates as a commercial resource.
AAPG members wishing to participate in this effort are asked to contact Art Johnson at [email protected].
To further contribute to our understanding of gas hydrates as a future energy resource, AAPG is planning a Hedberg Research Conference next fall that will bring together the gas hydrate research community.