Shale gas: controversy and resources

In this space we recently reported that a new assessment of the Marcellus Shale in the northeastern US by the US Geological Survey seemed to indicate that shale gas resources in the US may be a lot smaller than was previously thought. This, however, turned out to be incorrect. Below we give the correct story - and provide an overvi...

Shale gas: controversy and resources

On 23 August, the United States Geological Survey (USGS) released a new survey of the Marcellus Shale, so far the biggest shale gas field in the world. In this space, we reported that the outcome ‘was a serious disappointment to shale gas advocates’. We wrote that ‘it has forced the Energy Information Administration (EIA) of the US government to cut its estimate of the (technically recoverable) resources of Marcellus from 410 trillion cubic feet (tcf) to just 84 tcf.’

Quite an important issue, as Marcellus is by far the biggest shale gas resource in the US. Total technically recoverable shale gas resources in the US are estimated by the EIA at 750 tcf, of which Marcellus supplies 410 tcf . In other words, a downgrade of Marcellus to 84 tcf would mean a downgrade of total US shale gas reserves of 43% (from 750 tcf to 424 tcf).

Now USGS in its press release did not talk about a downgrade. In fact, it said in its press release that according to the new estimate, the Marcellus Shale contains ‘significantly more’ gas than was previously thought. But USGS was comparing the new results to their original estimate made in 2002, before the advent of hydraulic fracturing techniques. See here for the new assessment and here for the previous one.

The EIA's estimate of the Marcellus reserves of 410 tcf can be found here. The IEA did not base its estimate on the 2002 USGS study, but on work done by a consultancy, INTEK, and perhaps also on a study by study by Engelder (2009) of Penn State which estimated 489 Tcf of technically recoverable gas from the Marcellus. So, compared to the EIA’s estimate the new USGS study did seem to be a considerable downgrade. This, indeed, is what the New York Times reported in a news story on 24 August.

Before that, on 23 August, news agency Bloomberg had reported that the EIA would ‘slash its estimate of undiscovered Marcellus Shale natural gas by as much as 80 percent after an updated assessment by government geologists.’ Bloomberg added that the new estimate ‘supersedes an Energy Department projection of 410 trillion cubic feet’, quoting one Philip Budzik, an operations research analyst at the EIA.

This is essentially the story we reported on 1 September. We also quoted J. David Hughes, a geoscientist connected with the Post Carbon Institute, who noted that ‘the new estimates represent a considerable downgrade from the widely used study by Engelder (2009) of Penn State which estimated 489 Tcf of technically recoverable P50 gas from the Marcellus and the estimate of 410 Tcf published by the EIA in July, 2011, based on work done by its consultant INTEK. The new USGS resource estimates for the Marcellus are likely to be much more rigorous than the Engelder and EIA estimates. It should also be noted that the USGS estimates include gas underlying areas which are off limits for drilling but, as they are “undiscovered” resource estimates, they do not include the actual booked reserves of companies for SEC filings (which are very small by comparison).’

We also added some more informaton on Hughes. We noted that he wrote a study for the Post-Carbon Institute, Will Natural Gas Fuel America in the 21st Century?, in which he argued that the natural gas industry has propagated ‘dangerously false claims about natural gas production supply, cost and environmental impact’. The most significant of those ‘false claims’, says Hughes, is ‘one that has been bought hook, line and sinker by everyone from the Energy Information Agency (EIA) and the Obama Administration, to leading environmental groups – that the United States has a 100-year supply of cheap natural gas.’ Hughes’s report says this is ‘a pipe dream’. In fact, he writes, ‘the US faces a decline in domestic gas supplies in the very near future unless drilling rates quickly increase’.

However, we then got a comment from a reader, saying that the claim of an 80% downgrade was based ‘on a faulty reading of a USGS report by the New York Times’ Ian Urbina.’ The reader, Donald Hertzmark, wrote: ‘The USGS estimate was applied only to Marcellus areas that are not now under production or drilling, a very small part of the Marcellus. The USGS figure represents undiscovered reserves from these areas, not the entire Marcellus. This is not a restatement of reserves nor is it a downgrading. I have spoken with a USGS official familiar with these shale gas resource estimates and this person does not understand how the story got so confused.’

We checked this with the EIA and the USGS and the reader turned out be correct. A spokeswoman of USGS told us: ‘The USGS assessment is only of the undiscovered resources (not reserves) of the Marcellus Shale. Because they are "undiscovered," they are resources in those areas yet to be found (or drilled), thus outside of currently producing areas. Resources and reserves in currently producing areas are discovered or known, and we do not assess those.’

Thus, Bloomberg may have reported correctly that the EIA would ‘slash its estimate of undiscovered Marcellus Shale natural gas’, but apparently had not realized that this downgrade did not apply to the whole Marcellus Shale (nor had we).

We also checked the Bloomberg story with the EIA. Their spokesman replied with the following statement: ‘The reported interpretation of the statement [by Bloomberg] is incomplete and therefore inaccurate. EIA will incorporate USGS's estimate for the “undiscovered, technically recoverable” portion of the total technically recoverable resource base. However, that estimate is only a part of the total and, at the present time, there is not enough information available from the USGS to allow for estimations to be completed of inferred reserves. Both of those estimates would be combined with proved reserves to provide the total technically recoverable resource base as would be reported by EIA.’

So much for the Marcellus Shale controversy. We sincerely apologize for the confusion.

We further referred our readers to a number of sources for information on shale gas. First of all, we noted that a new study has been published in the scientific magazine Environmental Research Letters, which reports that shale gas production has considerably less impact on global warming than coal. The study, Life cycle greenhouse gas emissions of Marcellus shale gas, may be seen as a refutation of an earlier study from Cornell University that claimed that shale gas was worse for the the climate than coal.

And we gave an overview of other sources, which we reproduce here: