Washington, D.C. — The Office of Fossil Energy’s National Energy Technology Laboratory (NETL) has established that gas hydrate can and does occur at high saturations within reservoir-quality sands in the Gulf of Mexico. NETL—in collaboration with the U.S. Geological Survey, the U.S. Minerals Management Service, an industry research consortium led by Chevron, and others—recently completed a landmark 21-day gas hydrate drilling expedition that discovered highly saturated hydrate-bearing sands in two of three sites drilled.
Gas hydrate is a unique substance comprised of natural gas (almost exclusively methane) in combination with water. Gas hydrate 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. However, prior to this expedition, there was little documentation that gas hydrate occurred in resource-quality accumulations in the marine environment.
The Gulf of Mexico Gas Hydrate Joint Industry Project (JIP) Leg II expedition follows a 2005 JIP drilling program that focused on possible drilling hazards related to gas hydrate in fine-grained sediments. The latest expedition was designed to expand the understanding of gas hydrate in the Gulf of Mexico by specifically targeting systems thought to include high-quality (thick, porous, and permeable) sands.
NETL’s Dr. Ray Boswell, one of the leaders of the program, pointed out the expedition was completed on-time, with no incidents, and below the planned $11.2 million dollar budget. "The cooperation of government, industry, and academia was critical to the successful completion of this project," he said.
During the expedition, gas hydrate was found at saturations ranging from 50 percent to more than 90 percent in high-quality sands. The deposits were also found in close accordance with the project’s pre-drill predictions, providing increased confidence in the gas hydrate exploration and appraisal technologies.
Drilling discovered the first two resource-quality marine gas hydrate deposits in the world. Hydrates were found in a range of settings, including sand reservoirs, thick sequences of fracture-filling gas hydrates in shales, and potential partially saturated gas hydrates in younger systems. Researchers say these sites provide a wealth of opportunities for further study and data collection that will enable significant advances in understanding the nature and development of gas hydrate systems.
JIP Leg II also featured a number of technical advances, including the use of an advanced suite of logging-while-drilling tools that provided unprecedented three-dimensional images of hydrate-bearing sediments. In addition, the wells drilled at Walker Ridge, approximately 3,500 feet below the seafloor, were more than 1,000 feet deeper than any previous gas hydrate research well.
The operational success of JIP Leg II is due in large part to colleagues at the U.S. Mineral Management Service, AOA Geophysics, and Schlumberger who provided the initial appraisals of these targets. JIP Leg II operations were also supported by the Borehole Research Group at Lamont-Doherty Earth Observatory of Columbia University.
