A Marcellus Shale Primer
by Maren Leyla Cooke -- September 2010
An issue that has quickly dominated environmental concerns in our region is the prospect of deep gas drilling in the Marcellus Shale. The Marcellus formation lies beneath much of Pennsylvania and West Virginia, along with parts of Virginia, Ohio, and New York State. The shale layer, named for an outcrop near the town of Marcellus, NY, runs as deep as 9000 feet in some areas and underlies more than 30 million acres.
How did it get there? During the Devonian period, nearly 400 million years ago, the supercontinents Laurentia (later North America) and Gondwana (including what would become Africa) were coming together at the future Appalachian Basin. As marine organisms died, they settled to the bottom of a deep sea, along with silt from the eroding Acadia mountains nearby (which included things like barium, strontium, uranium, radium, and other heavy metals). Because of the warm climate, the sea was stratified and oxygen was quickly depleted at the bottom. Anoxic decomposition of the organics produced methane within the sediment; folks who compost can attest to the stinky result of anaerobic decomposition! Heat and pressure slowly transformed this mud into a dense black shale, and impermeable limestone layers above and below trap the gas in the formation where it has tantalized the energy industry for years.
Because the Marcellus shale is so very dense, gas does not travel freely through it. In gas-rich, porous sandstone, a vertical well can tap a large area -- but not so with this shale. Not until horizontal drilling techniques were developed in the 1990s did this broad, thin reservoir become accessible. With 200-500 trillion cubic feet of gas underground, this region has been called "the Saudi Arabia of natural gas" -- it is the largest on-shore natural gas reserve in the world -- and now energy companies are champing at the bit to extract it.
We know that as a fuel, natural gas is cleaner to burn and releases less carbon per unit energy than other fossil fuels (half as much as coal). However, getting it out of these deep reservoirs with current technology comes at a very great cost to the land, water, air, wildlife, and human health. Deep shale gas drilling has already been going on in other shale "plays" around the country for years -- first in the Barnett Shale in Texas, then in Oklahoma, Louisiana, Wyoming, and Arkansas. Now, deep-shale gas drilling is taking place in 32 states around the nation, including Pennsylvania. The ramp-up has been astounding.
What does the extraction process entail? At first blush, it sounds efficient -- a well is drilled straight down until it reaches the shale layer, then holes are bored horizontally in various directions for hundreds to thousands of feet. That way, one surface site can tap a large area of subsurface shale. However, that single surface site is much larger and more devastated than one might imagine. Although each well-head itself is relatively small, the well-pad surrounding it must be large -- typically several acres -- to accommodate all the necessary trucks, tanks, and machinery.
What is all that machinery for? Some of it is the drilling rig, of course, which goes away after a well is completed, but there's a whole lot more. Even with long horizontal well shafts in the shale layer, the methane doesn't just spurt out; it's tightly bound within the dense shale. A process called high-volume slick water hydrofracturing (or hydrofracking, fracking, or fracing), is necessary to shatter the rock and release the gas. Fracking fluid -- a mixture of water, sand (to prop open the cracks), and an often-undisclosed cocktail of chemicals to reduce friction, prevent corrosion, kill microbes, maintain viscosity, and other functions -- is pumped down into the shafts. Some of that fluid comes back up along with the gas, and in addition to the chemicals sent down are heavy metals (some of them radioactive) and salt (recall that the sediments were deposited at the bottom of an ocean, which then dried up) so the euphemistically named "produced water" is 5-10 times as salty as ocean water. A million or more gallons of this toxic brine is generated for each well.
Where does all this water come from? Millions of gallons of fresh water are drawn from our rivers and streams for each well, often seriously affecting flow rates and habitat for fish, invertebrates, plants, and the complex food webs that depend on them. Natural flow rates depend on the season, of course, and we can hardly expect drilling companies to alter their fracking schedule to account for drought conditions. On the way back up from the deep shale layer, highly contaminated frackwater can even leak through inadequate well casings (metal tubes surrounded by concrete that are installed in each well) out into the aquifers from which many residents draw their water. In any case, what comes back up is not fit to be returned to the watershed (especially considering the reduction in stream flow due to all the withdrawals), and generally sits in a great open pit (which can occupy several more acres, plus the mountain of soil and rock that was excavated to create it) for evaporation, as well as a few rounds of reuse down the well... before being covered and buried (to go where?) or trucked away for treatment or reinjection into the ground (potentially polluting aquifers elsewhere). Pipelines transporting fluids to and from the wellhead often leak, spilling unknown contaminants onto the land in between. The waste fluid is also full of VOC's (volatile organic chemicals like benzene, toluene, ethylbenzene, and xylene, many of which are known carcinogens or endocrine disruptors), so as long as it remains in the open brine pit it emits huge amounts of airborne pollutants (some operations even use misters to hasten evaporation, though others try to capture the volatiles to sell into the chemical industry). In an ironic twist (when we are trying to replace coal and oil), the methane itself is a potent greenhouse gas.
Combined with methane leaks and venting from well-heads, tanks, trucks, and pipelines and the copious diesel emissions and fugitive dust from construction equipment, drilling rigs, generators, trucks, and compressor stations, this produces a serious air-quality problem. Ground-level ozone (damaging to lungs, trees, and crops) and smog at rural drilling sites can reach levels comparable to large urban areas. All of this equipment is also noisy, of course, and the truck traffic alone is prodigious; a single well can require more than a thousand trips by giant tanker trucks, in addition to transporting equipment and materials on- and off-site -- so wear and tear on roads and bridges is also a concern for municipalities, along with local emergency services which suddenly have a much bigger job to do; in general the first-responders (often volunteers) are inadequately trained and equipped. Yet another burden on local people and communities is the impact on property values -- when residents are sickened by nearby drilling operations, they often have nowhere to go, as nobody else would want to buy their unhealthy homes.
Where does it all go? Wastewater from drilling operations cannot be treated effectively by
most conventional water-treatment facilities. Even if we assumed that the effluent could be effectively stored or treated, the fracturing process itself puts entire aquifers at risk. Over and over again residential wells, springs, and streams have been contaminated as toxic compounds have migrated from the shale or from poorly-sealed well-casings -- and over and over again,
the drilling companies have avoided responsibility by every means possible.
Texas, where all this has been done for years, does have the advantage of 12,000 spent wells for wastewater disposal. It is also fairly flat and semi-arid; there are no trout streams to pollute and only one natural lake. Water wells there tap deep aquifers, rather than our shallow wells into groundwater that can be contaminated by surface spills, dumps, or blowouts.
When drilling companies do replace drinking water supplies (and a 500-gallon "water buffalo" is a far cry from a freshwater spring used by a family for generations), they often do so on condition that the homeowner keeps mum about the whole experience; people have to sign nondisclosure agreements or the water buffaloes stop coming (this is just one of the many ways in which the companies don't play fair with landowners). And they don't seem to care about water supplies used by livestock, let alone wildlife.
Unfortunately, key federal regulations have been sidestepped, and the EPA's hands are tied: the Energy Policy Act of 2005 (based on the recommendations of Dick Cheney's secret energy task force) specifically exempts the hydraulic fracturing process (pioneered by Halliburton, Dick Cheney's former employer) from the Safe Drinking Water Act. In most cases, it is also effectively exempt from the Clean Air Act because individual wells are considered as sources, rather than entire wellfields. Drilling companies have not been required to disclose the contents of their proprietary fracking fluids (which would enable the confirmation of drilling-related contamination in wells and streams). Pennsylvania has been particularly hospitable to the extraction industry: the state Oil & Gas Act explicitly prohibits a municipality from restricting aspects of extraction operations that it regulates, thus preempting the municipality's right to self-government.
The Marcellus shale underlies 40 of Pennsylvania's 67 counties, and does not distinguish between remote rural areas and densely-populated cities. Surprisingly, the regulatory framework hardly differs either; as a result, gas companies have been planning well-sites and leasing land within the city of Pittsburgh. The process is dangerous wherever it occurs, but the stakes are much higher where there are more people. Accidents like the Marcellus fire in nearby West Virginia and the blowout in Clearfield County, PA last spring (both close on the heels of the Deepwater Horizon oil rig disaster in the Gulf of Mexico) would be catastrophic if they had occurred in a city like Pittsburgh. Further, as our region already has air-quality problems, we need to be even more vigilant about additional sources. In Dallas/Fort Worth, the fourth-largest city in the US, emissions from the drilling process turned out to exceed pollution from all the cars and trucks in that area.
In an attempt to catch up with the rush to frack, there has been a great deal of education and activism around this issue, both regionally and in Pittsburgh, a city that has paid more than its share of the environmental and health costs of industrial progress. Recently, City Council member Doug Shields introduced a bill to ban gas drilling within the city, called Pittsburgh's Community Protection from Natural Gas Extraction Ordinance. It was drafted with the help of the Community Environmental legal Defense Fund, and is based in part the Pennsylvania Constitution, which states that
The people have a right to clean air, pure water, and to the preservation
of the natural, scenic, historic and esthetic values of the environment.
Pennsylvania's public natural resources are the common property of
all the people, including generations yet to come. As trustee of these
resources, the Commonwealth shall conserve and maintain them for
the benefit of all the people."
Article I, Section 27
The bill has a strong chance of passing; six of nine Council members have pledged their support, which gives it a veto-proof majority. It will face legal challenges based on preemption, however. Another local effort is afoot which relies on zoning laws, an approach which may fare better under preemption but which may allow some drilling operations in the city.
However, even if this legislation holds up in court (which is not a sure thing, though neither were emancipation, women's suffrage, or legislative advances in civil rights), and drilling is banned in Pittsburgh proper, we need to think about our entire watershed. 90% of Allegheny County residents get their drinking water from the Three Rivers, and tens of thousands of wells are planned upstream from the Point. Contamination of a tiny mountain brook can certainly find its way to a municipal water intake.
At the state level, it has been an uphill battle to pass a moratorium on drilling (as has been done
in the New York City watershed) to give residents a chance to catch their breath and learn more about the implications of signing a lease, to allow the EPA and other agencies study the environmental impacts, and for the actual engineering to be refined to reduce some of the risks. The gas has been there for hundreds of millions of years; it isn't going anywhere for the next ten or twenty years. But part of Pennsylvania's gas rush is due to the drilling industry wanting to extract as much as possible before a "severance tax" is enacted. Such a tax would return a small fraction of the gas industry's profit to the Commonwealth from which the resources are being extracted -- Pennsylvania is currently the only state without a severance tax. Other states have severance taxes for oil, coal, gas, timber, sand, gravel, even seafood taken in coastal waters. Such a tax could help fund environmental restoration, infrastructure repairs necessitated by all the heavy trucking, public health measures, and initiatives to help make the transition to renewable energy. Unfortunately, both these efforts -- slowing the development of the Marcellus Shale and levying a severance tax -- will be even more difficult with the upcoming change of leadership (and the drilling companies donated hundreds of thousands of dollars to election campaigns).
So should we stick to coal, which still produces the lion's share of U.S. electricity? No; coal brings its own extraction hazards, from coal-mining deaths, subsidence, and acid-mine drainage to the horror of mountaintop-removal mining. And it is still true that coal is much dirtier than natural gas at the burning stage, what with fine particulate matter, sulfur dioxide and oxides of nitrogen, mercury and other heavy metals, acid rain, ground-level ozone, greenhouse gas emissions, and yet another waste disposal problem: large quantities of toxic fly ash.
What we do need is true-cost accounting for the energy economy (and everything else, for that matter), which factors in the real environmental and health costs of energy production and consumption. That would enable simple market forces to favor renewable energy and reward conservation. The cheapest energy is always the energy you don't have to generate, and the more expensive energy is, the greater the incentive to use less. Instead of subsidizing the oil and gas industries, let the money go to fund R&D for renewables and energy efficiency. Tax pollutants, figure out risks and hazards early on -- and require companies to pay for possible cleanups up front through bonding or other means. Finally, we need a cultural shift to an ethic in which stewardship and responsibility outweigh the longstanding American appetite for consumption, and common sense trumps comfort (think long johns and a sweater rather than cranking up the thermostat). We need to be a very different kind of role model in the world than we have been up to now.
Photos of drilling sites at http://marcellus-shale.us/ Data on wells, drilling permits, and impacts at http://www.fractracker.org/ .
The author maintains an environmental events listing, including many Marcellus events, at http://marenslist.blogspot.com/ .