Water and gas samples were collected from (1) nine shallow groundwater aquifers overlying Marcellus Shale in north-central West Virginia before active shale gas drilling, (2) wells producing gas from Upper Devonian sands and Middle Devonian Marcellus Shale in southwestern Pennsylvania, (3) coal-mine water discharges in southwestern Pennsylvania, and (4) streams in southwestern Pennsylvania and ...

The remarkable US growth of shale gas and the associated decrease in the US natural gas prices has catalysed an increasing interest of shale gas resource exploration in other areas of the world. Commercial drilling operations have not yet commenced, but exploration is taking place in some European countries, including the UK. Major environmental concerns, regarding the amount and the handling m...

The gas extraction technological developments of the 2000s have allowed shale gas production, which in the US has become a significant part of the total gas production. Such a significant change might have affected the long-run relationship between oil and natural gas prices postulated by several authors. By using monthly data of oil and gas prices, as well as gas quantities from 1997 to 2013, ...

Oil and natural gas from deep shale formations are transforming the United States economy and its energy outlook. Back in 2005, the US Energy Information Administration published projections of United States natural gas supply that stressed the need to develop an import infrastructure (1): by 2025, imports would account for almost one-third of United States consumption. When we compare those fo...

Nanopores are extremely developed and randomly distributed in shale gas reservoirs. Due to the rarefied conditions in shale strata, multiple gas transport mechanisms coexist and need further understanding. The commonly used slip models are mostly based on Maxwell slip boundary condition, which assumes elastic collisions between gas molecules and solid surfaces. However, gas molecules do not reb...

The large amount of nanoscale pores in shale results in the inability to apply Darcy's law. Moreover, the gas adsorption of shale increases the complexity of pore size characterization and thus decreases the accuracy of flow regime estimation. In this study, an apparent permeability model, which describes the adsorptive gas flow behavior in shale by considering the effects of gas adsorption, st...

Permeability is one of the most important parameters to evaluate gas production in shale reservoirs. Because shale permeability is extremely low, gas is often used in the laboratory to measure permeability. However, the measured apparent gas permeability is higher than the intrinsic permeability due to the gas slippage effect, which could be even more dominant for materials with nanopores. Incr...

where he is also Director of the Center for the Environment. He currently serves on President Obama's Council of Advisors on Science and Technology. He has authored more than one hundred articles on topics in geochemistry, geology, paleoclimatology, ocean-ography, energy technology, and energy policy. Over the last ten years, technological innovation has transformed U.S. energy resources. Geolo...

US shale gas production is generally expected to continue its fast rise. However, a cautious evaluation is needed. Shale gas resource estimates are potentially overoptimistic and it is uncertain to which extent they can be produced economically. Moreover, the adverse environmental effects of ever more wells to be drilled may lead to a fall in public acceptance and a strengthening of regulation....

Hydraulic fracturing is a technology used to extract natural gas from shale rock formations found deep beneath the earth. It raises many public health and environmental issues of concern to municipalities and planners, both urban and rural. These issues range from potential water contamination and air pollution to noise, dust, truck traffic, and even minor earthquakes. This article identifies r...