Significant Gas Resource Discovered in U.S. Gulf of Mexico

June/July 2009

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The U.S. Gulf of Mexico contains very thick sections of gas-hydrate-rich reservoir rocks, which have the potential to produce gas with current technology.

Recent drilling by a government and industry consortium confirms that the Gulf of Mexico is the first offshore area in the United States with enough information to identify gas-hydrate energy-resource targets with a potential for gas production.

Gas hydrate, a substance composed of natural gas and water, is thought to exist in great abundance in nature and has the potential to be a significant new energy source to meet future energy needs. Before this expedition, there was little documentation that gas hydrate occurred in resource-quality accumulations in the marine environment.

Above: Sites drilled during Legs I and II of the Gulf of Mexico Gas Hydrate Joint Industry Project (JIP). AC, Alaminos Canyon; AT, Atwater Valley; GC, Green Canyon; KC, Keathley Canyon; WR, Walker Ridge. [larger version]

"This is an exciting discovery because for the first time in the U.S. Gulf of Mexico, we were able to predict hydrate accumulations before drilling, and we discovered thick, gas-hydrate-saturated sands that actually represent energy targets," said U.S. Geological Survey (USGS) Energy Program Coordinator Brenda Pierce.

"We have also found gas hydrate in a range of settings, including gas hydrates in sand reservoirs, thick sequences of fracture-filling gas hydrates in shales, and potential partially saturated gas hydrates in younger systems," said USGS scientist Timothy Collett. "These sites should provide a wealth of opportunities for further study and data collection that will enable significant advances in our understanding of the nature and formation of gas-hydrate systems."

Above left: Assembling drill pipe and deploying logging tools from the Helix Q4000. [larger version] Above right: JIP Leg II used an advanced suite of logging-while-drilling (LWD) tools (examples shown above right), which provided unprecedented three-dimensional images of gas-hydrate-bearing sediment. Details about the LWD tools are posted on a Department of Energy Web site about the cruise. [larger version]

The U.S. Department of Energy (DOE), the USGS, the U.S. Minerals Management Service (MMS), and a group of U.S. and international energy-industry companies under the management of Chevron were responsible for conducting this first-ever drilling project to collect geologic data on gas-hydrate-bearing sand reservoirs in the Gulf of Mexico. Field operations during the expedition were also supported by AOA Geophysics, the Borehole Research Group at Lamont-Doherty Earth Observatory of Columbia University, Schlumberger, and the crew of the drilling vessel Helix Q4000. The most important technical accomplishments include:

• The expedition collected a comprehensive set of logging-while-drilling (LWD) data through expected gas-hydrate-bearing sand reservoirs in seven wells at three sites in the Gulf of Mexico.
• LWD sensors provided unprecedented information on the nature of the sediment and the occurrence of gas hydrate.
• The expedition discovered gas hydrate in both sand- and fracture-dominated reservoirs.
• The discovery of thick gas-hydrate-bearing sands validates the predrilling integrated geological and geophysical approach used to identify the targets, and provides increased confidence in assessing the energy-resource potential of marine gas hydrates.
• Gas-hydrate-bearing sand reservoirs 50 to 100 ft thick were discovered at the Walker Ridge and Green Canyon drill sites.
• The discovery of concentrated gas hydrate in sand reservoirs has made Walker Ridge and Green Canyon prime sites for future research drilling, coring, and production testing.

Above left: Drilling vessel Helix Q4000 at sea in the Gulf of Mexico. Photograph courtesy of Helix Energy Solutions. [larger version] Above right: Drill pipe deployed from the Helix Q4000 penetrated 1,000s of feet below the sea floor. [larger version]

The 21-day expedition, conducted in April and May 2009, was Leg II of the Gulf of Mexico Gas Hydrate Joint Industry Project (JIP). The 2005 JIP Leg I drilling program focused on possible drilling hazards related to gas hydrate in fine sediment. The primary objective of the JIP Leg II expedition was to collect a comprehensive suite of LWD data over gas-hydrate-bearing sand reservoirs and to identify sites for future drilling, logging, and coring programs. The ultimate goal of the current phase of the JIP effort is to gain further insight into the nature, formation, occurrence, and physical properties of gas-hydrate-bearing sediment for the purpose of both resource appraisal and gas-hydrate hazard assessment.

Additional information about USGS research on natural-gas hydrates is posted on the USGS Energy Resources Web site. To learn more about gas-hydrate research in the Gulf of Mexico and the results of the 2009 expedition, visit the DOE National Energy Technology Laboratory's National Methane Hydrates R&D Web site or contact Brenda Pierce, e-mail, bpierce@usgs.gov, telephone (703) 648-6421; or Tim Collett, e-mail tcollett@usgs.gov, telephone (720) 936-2372.

USGS Report of Methane Hydrate Off Southern California Sparks Media Interest March 2006

Gas Hydrate in the Northern Gulf of Mexico Has Puzzling Characteristics and Could Pose a Hazard to Deep Drilling July 2003

Gas Hydrates USGS

Energy Research and News USGS

The National Methane Hydrates R&D Program 2009 Gulf of Mexico JIP - Leg II U.S. Department of Energy

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June/July 2009

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in this issue:

cover story:
Submarine Ground Water Discharge Along the West Florida Shelf

Significant Gas Resource Discovered in Gulf of Mexico

Assessing Offshore Marine Sand Deposits

10th Anniversary of Sound Waves

USGS: Your Resource During Hurricane Season

Internship Programs at USGS Center in St. Petersburg

Open House in Menlo Park

Annual NGOM Science Meeting

June/July 2009 Publications List