The objectives of the DOE’s marine gas hydrate program are to:

• collect a full suite of in situ measurements and core samples to characterize the physical properties of marine methane hydrates;

• assess their potential response to possible production activities; and

• further delineate the occurrence and nature of gas hydrates in the US outer continental shelf.

More specifically, this new project, managed by the DOE’s Office of Fossil Energy’s National Energy Technology Laboratory, will characterize and prioritize known and prospective drilling locations with a high probability of encountering concentrated methane hydrates in sand-rich reservoirs.

A focused drilling program will acquire conventional cores, pressure cores, and downhole logs; will measure in situ properties; and will measure reservoir response to short-duration pressure perturbations.

DOE says that the field campaign will offer an ideal opportunity to deploy and to test several coring and hydrate characterization tools developed through previous DOE-supported research efforts.

Post-cruise analyses will determine the in situ concentrations, the physical properties, the lithology, and the thermodynamic state of methane hydrate bearing sand reservoirs.

DOE’s goal for the project is to use the collection and analysis of field data to strengthen the ability to estimate the occurrence and distribution of marine hydrates and to lay the groundwork needed to simulate production behavior from sand-rich reservoirs.

In addition to UT Austin’s Institute for Geophysics (UTIG) at the Jackson School of Geosciences, the Gulf of Mexico study includes researchers from The Ohio State University, Columbia University’s Lamont-Doherty Earth Observatory, the Consortium for Ocean Leadership and the US Geological Survey.

Estimates vary on the amount of energy that could be produced from methane hydrate worldwide, but the potential is huge. In the Gulf of Mexico, where the team will be sampling, there is estimated to be about 7,000 trillion cubic feet (TCF) of methane in sand-dominated reservoirs near the seafloor. That is more than 250 times the amount of natural gas used in the United States in 2013.

Hydrates have the potential to contribute to long-term energy supplies within the United States as well as abroad; many large global economies that lack clean and secure energy supplies have potentially enormous hydrate resources. Accordingly, other countries with high energy demands or limited resources—e.g. Japan, South Korea, India and China—have active methane hydrate research programs.

Distribution of known methane hydrate accumulations. Council of Canadian Academies (2008). Click to enlarge.

Methane hydrate is stable under high pressure and low temperatures but separates into gas and water quickly when warmed or depressurized, causing the methane to bubble away. This poses technical and scientific challenges to those working to eventually produce energy from the deep-water deposits.

The heart of this project is to acquire intact samples so that we can better understand how to produce these deposits.

—Peter Flemings, a professor and UTIG research scientist and the project’s principal investigator

The four-year project will be the first in the offshore United States to take core samples of methane hydrate from sandstone reservoirs, Flemings said, a delicate task that requires transporting samples from great depths to the surface without depressurizing them.

Carlos Santamarina, a professor at the Georgia Institute of Technology and a leading methane hydrate expert, said pressure core sampling is vital to gaining a better scientific understanding of hydrate-bearing sediments.

The technique is like taking a specimen inside a pressure cooker from thousands of feet below sea level, and bringing it to the surface without ever depressurizing the pressure cooker. With this technology, the sediment preserves its structure and allows us to determine all the engineering properties needed for design.

—Carlos Santamarina

It is not currently economically or technically feasible to produce substantial amounts of energy from methane hydrate, but Flemings said that could change as the science improves and world energy demand increases.

This could be analogous to gas or shale oil 20 or 30 years ago. None of us thought we were going to produce any hydrocarbons out of shales then.

—Peter Flemings