Water use in Marcellus Shale drilling "may not be as big an issue as we originally thought it was," a Pennsylvania Department of Environmental Protection (DEP) official told a natural gas forum on Capitol Hill in Washington, DC, last Wednesday.
Dana Aunkst, an engineer and DEP's acting deputy secretary for field operations, said the DEP analyses are determining that the average daily consumption in the shale industry is "no greater than one of our power plants." But he noted that the conclusions may be premature because they only have results for a couple of years and the industry has not completely ramped up at this point.
Aunkst identified eight major areas regulated by the DEP that are potentially impacted by shale gas development, with water-related impacts being the ones getting all of the recent attention.
"Most of the water is consumptively lost, meaning it is contaminated to the point where it has to be disposed of, and the common method for that is deep underground wells," said Aunkst, who has been working on long-term projections of how much water the shale gas industry is likely to require in his state.
Operating impacts on soil erosion and storm runoff into waterways is another issue caused by the six- to eight-acre well pads typically used in the Marcellus, Aunkst said, as well as the post-construction affects on the landscape.
On the largest current issue, wastewater impacts from shale gas production, Aunkst said much has been known for some time, citing Pennsylvania's 135-year history of oil and natural gas production. He emphasized that there are no current health hazards but said the state is taking "precautionary controls" and intends to require close monitoring of wastewater, along with "accelerating the frequency at which downstream drinking water intakes may have to monitor their water just to be on the safe side."
Including air quality issues, DEP is addressing all of shale's environmental impact questions, and it will continue to do so, Aunkst said.
At the same forum sponsored by the Environmental and Energy Study Institute, an independent engineering consultant, Lynn Pittinger, addressed shale gas from its long-term gas production standpoint, taking issue with current federal government and gas industry projections that place shale's total potential at the 225 Tcf level during the next 25 years.
"Shale is currently the main source of growth in the overall U.S. natural gas picture," said Pittinger, who recently collaborated with Art Berman of Labyrinth Consulting Services Inc. on a projection of shale's potential, separate from the Energy Information Administration (EIA) and industry projections. He and Berman take issue with shale gas being characterized as a "manufacturing process."
Both the quality and geology of various shale plays vary and the sensitivity of the overall production to wholesale gas prices keep shale production from having the consistency and repeatability generally associated with manufacturing, Pittinger said.
Looking at production data and ultimate recovery data from thousands of production wells during the past 18 months, Pittinger said that he and Berman have "come up with a different story" on shale gas than others in the industry or at EIA.
"The core areas of these [shale gas] wells are quite variable," he said. "The core areas are a small fraction of the overall play, and in some areas, the macro studies predicting hundreds or thousands of Tcf of shale gas potentially are not taking into consideration the range in quality or in price sensitivity. There are some of these plays that are commercially viable at today's prices, but to get full development will require increases in gas prices."