Table of Contents - Outline Format

From ShaleGasWiki

Jump to: navigation, search

New Sections and Material are Added Several Times Each Week Working Outline of Some Future Sections


Key Numbers

Glossary/ Key Concepts

Contents

Shale Gas: Introduction

Main article: Shale Gas: Introduction

"Because the exploitation of shale gas resources is still in its initial stages, and because many shale beds have not yet been tested," the U.S. Energy Information Administration reported in 2010, "there is a great deal of uncertainty over the size of the recoverable shale gas resource base.[1]

Composition

Main Article: Chemical Composition

"Shale gas" is natural gas that has accumulated in shale rock, and like all natural gas has physical characteristics that distinguish it from other fossil fuels.

Raw natural gas principally consists of methane (CH4), though gas from different sources can have different impurities such as condensates, water, carbon dioxide (CO2) and hydrogen sulfide (H2S) that must be removed before the gas can be transported into pipelines and sent to market.

Why Shale Gas is "Unconventional"

Most natural gas used today is called "conventional;" shale gas is "unconventional." Conventional gas is almost always found in the presence of oil, but characteristics that make gas "unconventional"--primarily shale gas, coalbed methane (CBM) and tight gas-- are difficult to define. In general, unconventional gas is lower in resource concentration, more dispersed over large areas, and requires well stimulation or some other extraction or conversion technology.

Size and Location of U.S. Shale Gas Deposits

Main Article: Size and Location of U.S. Shale Gas Deposits

Thanks to improved technologies and new discoveries, estimates of available fossil fuels have tended to remain steady or increase slightly over time despite continued production. Natural gas followed this pattern until the 1990s, when the development of shale gas began to dramatically accelerate estimates of the available domestic resources. According to the Energy Information Administration, about half of the total U.S. natural gas production by the end of 2012 will be from shale and other unconventional sources--up from less than 15% just two years earlier.[2].

In 2009 and 2010, analysts sharply raised their estimates of the natural gas resources in the continental U.S. In June 2009, the Potential Gas Committee estimated that total available supply would be 2074 trillion cubic feet (“tcf”), a 542 tcf increase over their forecast from 2007.[3] In March 2010, Cambridge Energy Research Associates estimated that available supply would be 3,000 tcf.[4] For comparison, the EIA estimates that U.S. consumption in 2008 was 23.2 tcf.[5]

To date, only a fraction of this potential shale gas is being produced. [6] Experts expect the recent dramatic upsurge in gas production to continue, [7] and that shale gas will become increasingly significant.

Relationship to "Oil Shale"

Development of Shale Gas

The first recorded instance of drilling for and then using natural gas occurred in ancient China.[8] Shale gas was first drilled in the U.S. in 1821 by a gunsmith named William Hurt, who lived Chautauqua County, New York--in the western part of the state, just south of Buffalo. To put this discovery in perspective of society and technology at the time, the newly re-elected president of the U.S. was James Monroe, a slave-owning Virginian who was one of America's Founding Fathers.

Hurt knew nothing about his Chinese predecessors. His well, which produced gas from an outcrop now known as the Devonian Fredonia shale, was drilled to 27 feet. Hollow logs serving as pipes carried gas to to adjacent homes, where it was used for basic lighting, and to the nearby town of Fredonia, where it became known as "town gas" and was mainly burned in street lamps. The dominant source of lighting fuel at that time in the U.S. was whale oil. After discovery of nearby conventional oil and gas about fifty years later, these other sources quickly overshadowed shale gas. Nearly all of this conventional oil and natural gas was captured via vertical drilling.

Geologists knew throughout most of the 1900s that numerous shale formations under the U.S. contained huge quantities of unconventional natural gas.[9] But no one was able to tap into these resources economically until advances in horizontal drilling and hydraulic fracturing in the 1990s. The first successful combination of horizontal drilling and hydraulic fracturing to capture natural gas from a deep shale formation occurred in 2003.[10]

Hydraulic Fracturing

Main article: Hydraulic Fracturing

Fracturing Fluid

Main article: Fracturing Fluid

Environmental Concerns: Overview

Main Article: Environmental Concerns: Overview

Extraction of shale gas raises complex environment-related issues, many of which seem encapsulated in the basic question, "How safe is hydrofracking?" Despite the technological complexity of fracking, an October 1, 2010 article in Fortune concludes, the answer to this question "may boil down to the amount of human error that people are ultimately willing to accept." [11] This, in turn, raises an even more important question, "How do risks and benefits associated with shale gas compare with the risks and benefits of fuels that people would be using if the shale gas was not available?"

Facts, Arguments and the Documentary Movie Gasland

Environmental Benefits

Comparison with other Fossil Fuels is Necessary

Main Article: Comparison with other Fossil Fuels is Necessary

A wide range of studies show that technological breakthroughs and advances in efficiency, conservation, and utilization of renewable energy not withstanding, the U.S. will obtain the vast preponderance of its power from fossil fuels until well into the 21st century. A U.S. Department of Energy (DOE) study reported in April 2009, for example, that "Although there is rapidly increasing momentum to reduce dependence on fossil fuels in the U.S. and elsewhere, the transition to sustainable renewable energy sources will no doubt require considerable time, effort and investment in order for these sources to become economical enough to supply a significant portion of the nation’s energy consumption." The DOE study then continues: "Indeed, the Energy Information Administration (EIA) estimates that fossil fuels (oil, gas, and coal) will supply 82.1% of the nation’s energy needs in 2030."[12]


The Energy Information Administration adds that "enhancing the energy efficiency and reducing the carbon intensity of a supply largely reliant on fossil fuels are fundamental steps towards a global low-carbon energy system."[13]


Thus, the differences between natural gas and other fossil fuels are important. Major unknowns in assessing these differences include the effectiveness and cost of technologies such as carbon capture and sequestration.[14]

Most environmental benefits provided by natural gas[15] emanate from its physical characteristics, primarily its four hydrogen atoms for each atom of carbon, which explain the differences that emerge when natural gas is compared with the other fuels--primarily coal and oil--that would otherwise be used. In The Carbon Age (2008), journalist Eric Roston cites this as part of the long-term shifting of the "carbon-hydrogen" ratio that began with the change from burning wood to coal.[16] Major environment-related differences between natural gas and other fossil fuels are most evident in emissions. Closely related is the role that natural gas plays as a bridge fuel, facilitating transition to renewableenergy. Differences between natural gas and other fossil fuels can also be seen in demands for water and land.

Other factors--including versatility and built processing, transmission and distribution infrastructure--also contribute to the growing use of natural gas.

Water Usage and Contamination

The Union of Concerned Scientists reported in September 2010 that:

The arsenic, mercury, lead,and other toxic substances contained in the 120 million tons of coal plant waste produced every year can severely contaminate drinking water supplies. Coal mining in the United States uses an estimated 80 million to 230 million gallons of water each day....The EPA estimates that strip mining of coal by mountaintop removal has buried almost 2,000 miles of Appalachian headwater streams—some of the most biologically diverse streams in the country.36 Natural gas-fired plants are less water-intensive than coal or nuclear plants. Still, extracting gas from shale deposits, such as those found in Texas,Pennsylvania, and New York, through a process known as hydraulic fracturing can potentially lower local water quality, as well as strain local water supplies.[17]

Reduced Levels of Emissions into the Air

Main Article: Reduced Levels of Emissions into the Air

"Since natural gas is the cleanest burning of the fossil fuels," a study published in 2009 by the U.S. government concludes, "an environmental benefit could be realized by shifting toward proportionately greater reliance on natural gas until such time as sources of alternative energy are more efficient, economical, and widely available." [18]

Compared to other fossil fuels, natural gas emits much less carbon dioxide and far fewer of what the Clean Air Acts lists as criteria pollutants--known hazards to human health, and, in many cases, also a prime source of urban smog. For example, coal produces more than 2,500 times the amount of sulfur dioxide than does natural gas and almost five times as much nitrogen oxide per Btu. Coal also produces almost 400 times the particulate matter.

Effects on Human Health and Longevity

Power Generation

Transportation

Calculating Real Costs

Main article: Calculating Real Costs

Vaclav Smil's Energy at the Crossroads (2003), [19] which Bill Gates cites as the book to read about energy,[20] argues that "the cost of military and political stabilization of the Middle East," and "the toll of respiratory illness caused and aggravated by photochemical smog created by car emissions" are among the chief externalities that must be considered as part of fuel costs.[21]

Natural Gas as Bridge Fuel

Main Article: Natural Gas as Bridge Fuel

"Bridge fuel" is often used to describe the role natural gas can play in augmenting and encouraging adoption of renewable energy by providing a steady source of power during time periods with wind or solar power may not be available. A 2009 report from the Center for American Progress, for example, begins:

Recent technology advancements make affordable the development of unconventional natural gas resources. This creates an unprecedented opportunity to use gas as a bridge fuel to a 21st-century energy economy that relies on efficiency, renewable sources, and low-carbon fossil fuels such as natural gas. [22]

Environmental Risks: Water

Overall Perspective on Water

Main article: Overall Perspective on Water

Development of shale natural gas can have two potential impacts on the water supply: (1) toxic chemicals from development of the well or emerging from deep underground might pollute aquifers or surface water; and (2) the substantial amounts of fresh water required may reduce the availability of water for industry, agriculture and other essential uses.


One increasingly common strategy is to reduce both risks by re-using water that has already served in a previous fracking treatment.


"Water supply and disposal issues," concludes a recent MIT study, "Could be addressed by requiring collaboration between operators on a regional basis to create integrated water usage and disposal plans. In addition, complete transparency about the contents of fracture fluids, which are for the most part benign, and the replacement of any potentially toxic components where they exist, could help to alleviate public concern.[23]"

Chemicals Can Contaminate Water

Main article: Chemicals Can Contaminate Water

Hydraulic fracturing of a shale formation involves the high pressure injection of fracturing fluid to stimulate and facilitate the flow of gas. While 98 to 99.5% of fracturing fluid consists of water and inert materials such as sand, the remainder includes chemicals that act as, among thing things, antibacterial agents, corrosion inhibitors, surfactants, friction reducers and scale inhibitors. When the fracturing fluid is returned to the surface as flowback, additional toxins that exist naturally in deep shale formations are also likely to be present.

According to recent study from the WorldWatch Institute, fracturing fluid is ‘highly unlikely’ to migrate directly from the shale formation through the bedrock into drinking water aquifers. The primary risk to aquifers, local rivers and streams comes from improper handling of flowback at the surface or poor well construction that allows fluids to leak into aquifers from the wellbore near the surface. Proper handling of chemicals, disposal of flowback, construction of well casings, and proper execution of well completion and cementing techniques can substantially reduce the risks of water contamination.

Water Usage

Main article: Water Usage

A typical shale natural gas well can use 3-6 million gallons of water, with 70% or more required for hydraulic fracturing. On a per unit of energy basis, however, this is substantially less than the water required to produce coal, uranium or oil from tar sands. Additionally, if used to replace coal for electricity production, a typical natural gas well can reduce water usage by 75 million gallons during generation.

Gas producers are developing new ways to reuse more of the flowback for future hydraulic fracturing operations. Such recycling reduces water usage and disposal risks and can provide economic savings for operators.

Recycling Flowback Water

Main article: Recycling Flowback Water

Reusing water involves a range of technologies, employed at the well-site, and then blending flowback with clean water. Physical and chemical wastes removed from the water may also be recycled.

Environmental Risks: Air Quality

Main article: Air Quality Impact

Various stages of shale gas development can have three primary impacts on air quality: (1) Methane is a potent greenhouse gas with a global warming potential 25 times greater than CO2[24]; during the production of natural gas, some methane can be intentionally or unintentionally released into the atmosphere; (2) Natural gas condensates release volatile organic compounds ("VOCs") as they evaporate; VOCs contribute directly to the production of ozone and smog. At least one VOC, benzene, has been shown to cause cancer. [25] The amount of natural gas condensates and therefore, the amount of VOCs can vary significantly by well;[26]; and (3) Nitrogen oxides ("NOx"), particulate matter and other pollutants are emitted by internal combustion engines that are used to drill the well, produce and process the natural gas, and transport equipment and materials to and from the drill site.

Each of these categories of emissions pose direct risks to human health. See also, Fewer Emissions.

Environmental Risks: Land

Land Use

Main article: Land Use

An April, 2009 study published by the U.S. Department of Energy concludes that:

One consideration associated with traditional gas development has been the surface disturbance required for access roads and well pads.... [H]orizontal drilling can significantly reduce the overall number of well pads, access roads,pipeline routes, and production facilities required,thus minimizing habitat fragmentation, impacts to the public, and the overall environmental footprint...experience to date indicates that the use of horizontal well technology will significantly decrease the total environmental disturbance. [27]


The size and degree of disruption on areas used for drilling operations depend primarily upon the number of rigs and what the company intends to accomplish on-site. If a horizontal well is drilled, for example, a 5-10 acre surface disturbance can be expected.

Seismic Impact

Main article: Seismic Impact

Hydraulic fracturing creates small shear slip events within the shale formation that are in some technical ways similar to earthquakes and are known as microseismic events. These tend to be quite small and release less than one billionth the amount of energy of an earthquake that is large enough to cause damage at the surface. All of this can be tracked with microseismic monitoring.

Noise, Traffic and Other Problems

Main Article: Noise, Traffic and Other Problems

Extracting shale gas is a complex, industrial operation that has a wide range of impacts, many of them negative, on local communities. A study published by the U.S. Department of Energy documents how:

The process of shale gas development, especially drilling and hydraulic fracturing, can create short-term increases in traffic volume, dust and noise. These nuisance impacts are usually limited to the initial 20- to 30-day drilling and completion period. Along with increases in traffic volume, damage to road surfaces can occur if design parameters for traffic volume and weight loads are exceeded.[28]

"Although the impacts at a given drill site are concentrated in the three-four week drilling and well completion period," another study notes, "in regions where companies are drilling multiple wells, these conditions overlap and will generally persist much longer."[29]

References

  1. ↑ U.S. Energy Information Administration, Annual Energy Outlook 2010 With Projections to 2035, pp. 40-41.
  2. ↑ Source
  3. ↑ To be added
  4. ↑ To be added
  5. ↑ To be added
  6. ↑ EPA
  7. ↑ [http://www.epa.gov/sectors/pdf/oil-gas-report.pdf. An Assessment of the Environmental Implications of Oil and Gas Production: A Regional Case Study. Environmental Protection Agency.2010.]
  8. ↑ Needham
  9. ↑ Need citation
  10. ↑ Need Citation
  11. ↑ "Odorless, Colorless: The Quiet Rise of American Big Gas," October 1, 2010.
  12. ↑ "Modern Shale Gas Development in the United States: A Primer," p. 6.
  13. ↑ CO2 Emissions From Fuel Combustion: Highlights, 2009, p. 9.
  14. ↑ Wind and solar power, in turn, create their own environment problems; wind generates noise, for example, and solar transmission lines may disrupt wildlife.
  15. ↑ XX per cent of the natural gas used in the United States today is shale gas; this percentage is xxx.
  16. ↑ N.Y: Walker & Company, p. 211.
  17. ↑ "The Energy-Water Collision: 10 Things You Should Know"
  18. ↑ "Modern Shale Gas Development in the United States: A Primer," April, 2009, p. 6.
  19. ↑ Cambridge, Massachusetts: MIT Press
  20. ↑ [Need cite from his blog
  21. ↑ P. 361.
  22. ↑ Natural Gas: A Bridge Fuel for the 21st Century, John D. Podesta and Timothy E. Wirth August 10, 2009 Center for American Progress Energy Future Coalition p.1.
  23. ↑ http://web.mit.edu/mitei/research/studies/report-natural-gas.pdf pp.15-15
  24. ↑ An Assessment of the Intergovernmental Panel on Climate Change. IPCC. 2007.
  25. ↑ Need source
  26. ↑ Need source
  27. ↑ "Modern Shale Gas Development in the United States: A Primer," p. 43 and p. 47.
  28. ↑ "Modern Shale Gas Development in the U.S.: A Primer," p. 49.
  29. ↑ Need cite.


Retrieved from "http://shalegaswiki.com/index.php/Table_of_Contents_-_Outline_Format"
Personal tools