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...

Wastewater produced by hydraulic fracturing (" fracking ") for natural gas in the Marcellus Shale is already overwhelming disposal options and will continue to do so as gas development increases, according to newly published research. The investigation did not evaluate environmental consequences of the wastewater. But lead author Brian Lutz, an assistant professor in the Kent State University D...

In this paper we analyze by means of numerical simulation the mechanisms and processes of flow in two types of fractured tight gas reservoirs: shale and tight-sand systems. The numerical model includes Darcy’s law as the basic equation of multiphase flow and accurately describes the thermophysical properties of the reservoir fluids, but also incorporates other options that cover the spectrum of...

Today, many governments are considering the exploration and production of unconventional resources, shale gas in particular, for reasons of security of supply and reduction of import dependency. Large-scale development of these resources promises to significantly lower import dependency of gas supply of many countries. Whether the promise will be met remains uncertain though, not only because o...

The Haynesville Shale is a subsurface rock formation located beneath the Northeast Texas/Northwest Louisiana border near Shreveport. This formation is estimated to contain very large recoverable reserves of natural gas, and during the two years since the drilling of the first highly productive wells in 2008, has been the focus of intensive leasing and exploration activity. The development of na...

The rapid rise of shale gas development through horizontal drilling and high volume hydraulic fracturing has expanded the extraction of hydrocarbon resources in the U.S. The rise of shale gas development has triggered an intense public debate regarding the potential environmental and human health effects from hydraulic fracturing. This paper provides a critical review of the potential risks tha...

In April 2011, we published the first comprehensive analysis of greenhouse gas (GHG) emissions from shale gas obtained by hydraulic fracturing, with a focus on methane emissions. Our analysis was challenged by Cathles et al. (2012). Here, we respond to those criticisms. We stand by our approach and findings. The latest EPA estimate for methane emissions from shale gas falls within the range of ...