Marcellus Shale
"There is no topic more important to the current and future lives of our young people, here in Pennsylvania, than the topic of shale gas development. The issue has been clouded by campaigns of misinformation with promises of everything from economic renaissance to environmental apocalypse. For these reasons, 211 Science is committed to teaching young people the importance of understanding that, in the current age of information, they must pay close attention to every single source of information that they encounter and understand that the message is relative to the perspective of the provider."
- Mr. Martella

I. Getting ready to learn

Watch the following videos, keeping these questions in mind:

1. Who posted the video?
2. What do you think the purpose of the video is?
3. According to the video, what are the positive impacts of shale gas drilling and production?
4. According to the video, what are the negative impacts of shale gas drilling and production?
5. How do you feel about the process after viewing the first video? How about the second? The third?

Video 1

Video 2

Video 3

*Notes and information via
Photos courtesy C. Ruppen

The Marcellus Shale is named for a distinctive outcropping near the village of Marcellus, New York, just to the west of Syracuse.It is a unit of marine sedimentary rock that extends throughout much of the Appalachian Basin. The shale contains organic materials that break down to form natural gas. The natural gas is concentrated in pores throughout the shale formation. Estimates of the amount of natural gas in the Marcellus formation exceed 250 trillion cubic feet. It ranges in depth, but this Devonian formation is generally found from 4000 to 8000 ft. under the surface.
external image marcellus3_h.jpg

Interactive Timeline

  • Types of Wells
There are two types of gas wells on Marcellus Shale, horizontal and vertical.
  • 1) Horizontal wells, which are first drilled down then gradually curved and drilled horizontally, require much more water for well completion than vertical wells. Water requirements in early Marcellus gas wells have averaged 4 million gallons per well.
  • 2) Vertical wells, the type of gas wells traditionally drilled in the past, are drilled straight down without any laterals extending horizontally. Water requirements are much less, often under 10% of the water required for a horizontal well. Gas production is usually less as well.
Marcellus Drill Rig in Washington County (courtesy C. Ruppen)

Fracking is slang for hydraulic fracturing, and both terms describe the process used to frack (or frac) Marcellus Shale gas wells. To release methane from shale, high pressure is used to crack the shale formation. While there are alternatives to water for fracking gas wells (like nitrogen) production companies prefer to use water since higher hydraulic pressures can be created. Some reports indicate these pressures can reach as high as 10,000 to 15,000 psi (pounds per square inch). Chemicals are added to the water and sand for the 'slick water' hydraulic fracturing commonly used on Marcellus wells.

Fracking Chemicals
a. FracFocus (chemical registry list)
  • The total volume of the chemicals introduced into the fracking fluid is less than 1%. 99% of the fluid is a combination of sand and water.

Hydrofracking Simulation

  • Flaring
After a Marcellus gas well is drilled and hydraulically fractured, open flaring is often used to test production of the well. Since flaring releases greenhouse gases, such as methane, into the atmosphere, the EPA and Pennsylvania DEP enforce limited air quality regulations around Marcellus Shale natural gas wells and facilities (Most gas sites are permitted individually instead of cumulatively).
Photo: Caelan Borowiec via
  • Natural Gas Pipeline Construction
Drilling is not the end of the process. Once the wells start flowing, it is necessary to transport the gas from one point to another.
Pipeline Construction pipeline construction

  • Environmental Concerns/Issues
1) EPA air quality regulations- 11,000 new wells a year and about 1,200 existing wells will be fitted with devices that capture methane gas. The drilling companies have 3 years to phase the new technology in. Methane is a far more powerful greenhouse gas than carbon dioxide when released directly into the atmosphere. Often considered volatile organic compounds (VOC's), these gases may react with sunlight to create smog. This technology is needed immediately, as a 2015 report on air quality by the American Lung Association lists the Pittsburgh area in the top 10 for the worst air in the country.

2) Brine wastewater- 20-30% of the water used in fracking (each well may use up to 6 million gallons of water) may return to the surface as what we call flowback. This water is extremely salty. It is also extremely expensive and difficult to treat. It continues, however, to be sent to sewage treatment plants (which are not equipped to clean it) and then dumped back into rivers like the Monongahela.

3) Deep injection wells- These wells, drilled several thousand feet deep, accept wastewater in their permeable rock layers. Basically, we pump brine and other types of polluted water deep down into porous rock layers that are capped by nonporous layers. This will contain the polluted water and store it deep underground. Scientists have recently concluded that earthquakes in Oaklahoma and Ohio are man-made, and the epicenters of these quakes have been located at deep injection well sites.

4) Chemical pollution- Many of the chemicals that drillers use are "proprietary" (like special sauce on a Big Mac or the formula for Pepsi). This means that drillers may not have to release the names of all of the chemicals that they use. This is permitted by the Halliburton Loophole, which was a part of the 2005 energy bill passed by the Bush administration. Reports of excess methane, butane and propane have been found in water wells near drilling sites. Although these gases occur naturally, in coal seams for instance, some contamination has been linked to natural gas wells.

5) Impacts on the biosphere, geosphere- Although drilling operations, like mining operations, must end with "reclamation" or restoration, processes such as mountaintop removal and deforestation leave ecosystems as a shell of what they once were.

Hey, what about those "JOBS" for Pennsylvanians?

Marcellus Shale Coalition says:
Corbett Administration says:
Actual data says:
According to the most recent data available, the natural gas industry has created some 20,000 jobs over the last 8 years in PA. This is far less than what the industry promised at the early stages of the shale gas boom in the state. The simple truth is that 0.5% of the 6 million people working in PA are employed directly by the natural gas industry.