When the U.S. shale boom is over — however many decades off that might be — will the country find another abundant source of natural gas to tap?

Texas researchers are among those trying to find out. They are investigating another natural gas resource that could turn the energy world upside down: methane hydrates.

The flammable ice-like compounds are trapped in rocks deep below the ocean’s surface and in permafrost on land. They have sparked wide interest from energy companies and countries and have showed up in the plot lines of the revived television drama Dallas.

In 2012, the U.S. Department of Energy declared that “methane hydrates may exceed the energy content of all other fossil fuels combined,” and that they “could ensure decades of affordable natural gas and cut America’s foreign oil dependence.” 

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But for now, methane hydrates are expensive to extract, and as volatile compounds, they can be dangerous when disturbed. Large, sudden releases are thought to potentially unleash tsunamis or worse. And much is still unknown about the resource.

In November, the Department of Energy awarded $5 million in grants to researchers studying the resource. A $1.7 million chunk is going to the researchers at the University of Texas at Austin’s Department of Petroleum and Geosystems Engineering, who are leading a collaboration with Ohio State University and Columbia University's Lamont-Doherty Earth Observatory.

Hugh Daigle, an associate professor at UT-Austin and lead researcher on the project, chatted with The Texas Tribune about the potential of extracting natural gas from methane hydrates — a compound he calls “captivating.”  

The following is an edited and condensed transcript of the interview.

TT: Scientifically speaking, what is a methane hydrate?

Daigle: At certain temperatures and pressures, water will arrange itself into this lattice structure. When certain molecules are present, like methane or carbon dioxide, it forms a hydrate — basically a crystal in which water molecules are arranged around what’s called a guest molecule. In a methane hydrate, methane is the guest molecule.

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TT: Where are these hydrates typically found?

Daigle: Because they require low temperatures and high pressures, we usually find hydrates in the shallow sediments and deeper portions of continental margins (a zone of the ocean floor between the thin oceanic crust and the thick continental crust). There are a lot of hydrates in the Gulf of Mexico just off of the continental slope — in the area we consider the Deepwater Gulf. There are also a lot off the coast of South Carolina and North Carolina. They really seem to be present everywhere we look, because there’s a lot of methane out there.

TT: What countries are most interested in methane hydrates and why? 

Daigle: They are a potential energy resource. They are made of methane — the smallest natural gas molecule. A lot of countries that don’t have a lot of conventional natural gas resources are considering trying to produce methane from hydrates — because hydrates are pretty much everywhere. That includes the Koreans and the Japanese. I know the Indians are interested in this, possibly China, maybe Indonesia and some other places.

TT: It’s clear why energy producers here would be following developments in methane hydrate research: They are looking for more resources to tap in the future. But are there other practical applications for the research for the U.S.?

Daigle: The most immediate practical application would be pinpointing exactly where methane hydrates are and how to avoid them. They are a hazard when you’re trying to drill through them. If you’re out in the Deepwater Gulf of Mexico trying to drill a well, you have to drill through a zone where hydrates could possibly be formed, and you want to avoid them. Also, hydrates will form in oil pipelines if the pressure and temperature conditions are right.

TT: What happens if a driller unintentionally runs into the hydrates?

Daigle: What happens is that the hydrate will turn into water plus methane gas, and that is accompanied by a very large volume expansion. I think it’s 1 cubic foot of hydrate will produce somewhere around 170 cubic feet of gas. As you can imagine, that would cause all kinds of pressure-control problems. That’s the whole reason that people try to avoid them.

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TT: Are there any notable incidences when methane hydrates have caused problems for drillers? 

Daigle: Hydrates were involved in the containment efforts of the Macondo well (the 2010 explosion at BP’s Deepwater Horizon drilling rig). The containment dome that workers attempted to put over the well got clogged by hydrates coming up from the sea floor. Because of that association, I get a lot of people asking, “Wasn’t the well blowout caused by hydrates?”

TT: So it wasn’t?

Daigle: No, the hydrates were only a problem during the containment efforts.

TT: Since methane is a far more potent greenhouse gas than carbon dioxide, does this issue have implications for the climate?

Daigle: Methane hydrates have been implicated in some major and abrupt changes in climate through the past 60 million years or so. The most famous was about 55 million years ago. There was a large increase in global average temperature, and there’s some research that’s been done that’s lead some people to believe that the melting of the hydrates and release of the methane into the seawater, and eventually into the atmosphere, was in part responsible for this.

TT: So what’s the focus of your research?

Daigle: We’re focusing more on the oil and gas exploration side, and somewhat on the geological side. We want to understand how big accumulations of hydrates form locally. We have large surveys that tell us in a very broad sense how much methane is there, and how many hydrates there are. It tends to concentrate in different areas. So we’re interested in looking at what conditions inside the sediment favor the formation in those areas.

TT: How long might it be until we get more concrete answers to some of these big questions about the hydrates?

Daigle: We’re using a large basin model. So it’s a big computer model, and right now we’re getting it up and running, and making sure it’s giving us reasonable answers. We hope to be done with the initial model testing by this summer, and we can get going on our main task of trying to run these simulations sometime in the next year or so.

TT: Will this project help bolster UT's reputation in the energy world?

Daigle: Texas has historically been an area of expertise for the oil and gas industry, and we view that as an extension of that.  So having this research centered here is a big part of that, and we think that’s fulfilling part of the mission of this university.

Disclosure: At the time of publication, the University of Texas at Austin was a corporate sponsor of The Texas Tribune. BP America and BP Corp. North America were corporate sponsors in 2010-12. (You can also review the full list of Tribune donors and sponsors below $1,000.)