Two examples of shale-dominated overburden are shown in Figure 2. Low keff makes intuitive sense because the rocks must have low permeability in order to have trapped buoyant fluids (i.e., oil and natural gas) over timescales of tens to hundreds of millions of years (Connolly et al., 1990a, 1990b; Stueber and Walter 1991; Thornton and Wilson 2007).
Barnett Shale was the first successful example of shale gas production at commercial scale and is providing a production of about 0.50 trillion cubic feet (Tcf) per year of shale gas (e.g. EIA 2015).
The Marcellus is an example of shale gas, natural gas trapped in low-permeability shale, and requires the well completion method of hydraulic fracturing to allow the gas to flow to the well bore.
In the present study, the Lower Silurian shale from the Fuling Block was taken as an example to establish a geological model of shale gas storage capacity and loss (Fig. 7).
Examples of oil-bearing shales are the Bakken Formation, Pierre Shale, Niobrara Formation, and Eagle Ford Formation.
Technological change 3D printing and robotics, for example—or the emergence of shale oil and gas as cheap forms of energy may deliver a big boost.
Examples of fluid injection in shale reservoir hydraulic fracturing and waste disposal operations have been provided toward better understanding of the predictive methodologies for induced seismicity and preventive effort for sustainable and safe unconventional operations.
For example, the primary slit pore of shale narrows because of CO2 adsorption-induced swelling (see Fig. 11, marked A) (Yin et al. 2016).
Poland, for example, is "already tendering for exploration of shale gas," she said.
In Britain, for example, the Treasury is in favor of shale exploration to bring down domestic prices and increase energy security, while the Department of Energy and Climate Change "is very dubious, and it's a major battle," said Paul Stevens, an energy expert at Chatham House, a research institute based in London.
UNGDO have concentrated where large formations of shale exist, for example, the Barnett Shale in Texas, the Utica Shale in Ohio, and the Marcellus Shale in Pennsylvania [ U.S. Geological Survey (USGS National Assessment off Oil and Gas Resources Team and Biewick 2013].
