Marcellus Shale Gas Volume in Question

Marcellus shale drilling rig in Roulette, PA (click to enlarge)

The latest debate over Marcellus shale gas isn't about hydraulic fracturing, or fracking, but over how much gas there is to be removed. The U.S. Geological Survey (USGS) recently published its estimate of how much gas is trapped in Marcellus shale and can be extracted with current technology, but the figures differ dramatically from past estimates. Technology Review reports that the USGS's estimated volume for the shale deposit is 84 trillion cubic feet (TCF), a figure which is approximately 80 percent lower than the estimate released earlier this year by the Energy Information Administration, an agency of the U.S. Department of Energy.

Question of how much gas dependent on technology

The shale formation in question lies beneath portions of New York, Pennsylvania, Ohio, and West Virginia, and may be the largest deposit of shale gas in the United States. But the question of exactly how much gas lies there is a continuing debate. The new USGS figure is the latest figure in a history of dramatically differing estimates. The previous USGS estimate from 2002 was set at only 2 TCF, but improvements in fracturing and drilling technology as well as 3D seismic imaging were in part responsible for the increase in figures.

Whatever the figure, deposit is highly significant

Other sources have estimated the recoverable gas deposits to be as significant as 489 TCF. Regardless of how much gas is actually available, Francis O'Sullivan, an engineer at the MIT Energy Initiative who analyzed supply issues for a study of the future of natural gas released by the initiative in June, told Technology review that regardless of which figure is correct, there is a very sizable amount of recoverable gas in the shale formation. O'Sullivan estimates:

[...the Marcellus formation] could, at its peak, contribute 10 to 15 percent of the gas produced in the U.S. "What that means is that whether or not you have 200 TCF, 400 TCF, or 80 TCF of recoverable resources is quite moot at this point, and will be moot for 20 years."

Marcellus Shale Deposit. Click to enlarge.

Not volume, but safety--a challenge for chemical engineers

Commenting on the evolution of technology that will continue to increase how much gas is actually recoverable, O'Sullivan also noted in the interview, "The 20-year time horizon is a very long time in the context of technology in the gas space, and in the context of broader energy technology."

While the debate on fracking may continue, there is little debate that there is a significant deposit of natural gas that could be incredibly important to the country's future. It will be up to chemical engineers and others to find new ways to capture the gas through environmentally sound practices.

If you didn't see the amusing but informative music video about fracking and the environment featured on ChEnected earlier this year, check it out here.

Will shale gas be as significant as predicted, or will new energy alternatives change this?

Photos: Drilling rig, Wikimedia Commons/Laurie Barr
Illustration: Marcellus shale deposit, USGS


May's picture


Robert S's picture

This could be such a game changer and there is still so much uncertainty. "This American Life" did a really interesting piece on this focusing on the two professors on opposite sides of the issue and the town at the epicenter. All the money coming from industry makes it really hard to have any opinion other than there is a lot of easy gas.

I feel the same way, Robert. I know that many of the people in this region are confused and have mixed feelings as well. My parents live in SW Pennsylvania, so I've seen a bit of this firsthand. There are farmers who have supposedly become millionaires when a well produces gas, and that is certainly alluring. At the same time, people worry about the environmental dangers. I'd personally like to think that recovering this gas could be done safely with current techniques if done properly, but I'm concerned there aren't enough safeguards and checks to keep drillers from either making serious mistakes or simply foregoing safe practices to quicken or cheapen the process. I wasn't aware of the episode on This American Life but thought I'd post a link for anyone interested: .