A joint federal agency, 15-day research expedition in the northern Gulf of Mexico (GoM) yielded high-resolution seismic data and imagery that will help refine characterizations of large methane hydrate resources in the US Outer Continental Shelf, according to a news release.

According to the US Department of Energy’s (DOE) Office of Fossil Energy (FE), the information will be used to refine estimates of the nature, distribution, and concentration of gas hydrate in the vicinity of 2009 drill sites. Gas hydrates are ice-like substances formed when certain gases combine with water at specific pressures and temperatures, and represent a potentially vast future energy resource.

New data and imagery from the expedition, planned by the DOE, US Geological Survey (USGS), and Bureau of Ocean Energy Management (BOEM) and conducted by the USGS, also will help assess how useful specialized seismic data may be to estimating hydrate saturations in deepwater sediments, the release said.

Using low-energy seismic sources, USGS scientists collected details about the nature of the gas hydrate reservoirs and about geologic features of the sediment between the reservoirs and the seafloor, the release said. The new data also provide information about how much gas hydrate exists in a much broader area than can be determined from standard industry seismic data, which is typically designed to image much deeper geologic units.

The data were collected at two locations in the GoM where the three federal agencies partnered with an industry consortium to conduct a drilling expedition in 2009. That expedition discovered gas hydrate filling between 50% and 90% of the available pore space between sediment grains in sandy layers in the subsurface, according to the release. These reservoirs are expected to be representative of the 6,700 Tcf of gas that BOEM estimates is housed in gas hydrates in sand-rich reservoirs in the northern GoM.

In coming years, DOE, USGS, and BOEM will continue their collaborative investigation of gas hydrates in the northern GoM and other locations across the world, the release said.

Offshore