Chapter 10 Fossil Fuels

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Chapter 10 Fossil Fuels

• Fossil fuels name derived from the deriva-tion
  of coal and petroleum products from organic
  sources.
• Most fossil fuels meet the definition of as
  Nonrenewable resources. Coal takes millions of
  years to form and mature. Small amounts of
  methane form within landfills/ repositories of
  human/animal waste in short time periods, but
  large quantities require more time. Crude oil is
  thought to require at least 1 million years to
  form.

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• Collectively, coal and hydrocarbons (oil gas)
  form in areas suitable for large scale biomass
  accumulation and preservation.
• On land, long-persisting terrestrial ecosys-tems
  of high productivity, e.g., Mississippi Delta
  swamps, Everglades, Okefenokee Swamp modern
  analogues for coal and methane accumulation.
  Slow movement of water through these ecosystems
  results in anoxic (anaerobic, stagnant)
  conditions. The oxygen-poor, sulfidic (sulfur
  retaining) conditions are acidic and unfavorable
  to most bacteria resulting in slow decay rates
  preservation of organics.

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Gulf of Mexico as a favorable site for
pre-sent biomass accumulation future fossil
fuel generation.
Terrestrial or-ganics in delta sediments. Marine
organics preserved in deep water. Re-striction
of cur-rents between Cuba Yucatan, Cuba
Florida, depth of Gulf anoxic bottom?
From http//www.gulfbase.org/facts.php
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• In marine ecosystems, restricted basins with
  poor bottom circulation preserved marine snow
  as organic rich shales. Shallow, back-reef areas
  restricted shallow basins in warm climates may
  yield organic rich limestones.
• Black Sea largest example of an anoxic sea,
  6,000 feet deep, normal ecosystem in upper 300
  to 450 feet. Straits of Bosporus shallow,
  narrow seaway to Mediterranean Sea, little water
  exchange.
• http//en.wikipedia.org/wiki/Black_Sea

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• After burial by subsequent layers, heat
  pressure cook the organics, producing a wide
  variety of hydrocarbon molecules, ranging from
  heavy tar to methane. Some-times methane is
  formed by heat crack-ing larger petroleum
  molecules and sometimes it is formed directly
  from degraded plants.
• Usually, organic-rich source rocks are too
  fine-grained to serve as reservoir rocks. After
  the maturation process, if path-ways are
  available, oil will move from areas of high
  pressure to low pressure.

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Pathways may be fractures or pore spaces
between sedimentary grains. Shallower depths
less pressure. Oil Gas are lighter than water,
rise until trapped by a cap-rock. In this
case, this is an anticline (a structural trap).
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• Coal Most common fossil fuel. Formed from
  thick accumulations of plant material. Grades of
  coal are deter-mined by chemistry of deposition
  heat/ pressure history after burial compaction.
  Anoxic conditions preserve organics, but also
  facilitate deposition of sulfur com-pounds
  uranium compounds.
• Table 10.1 lists different grades ranging from
  Lignite (poorest quality) to Anthracite (best
  quality). Anthracite is often difficult to mine
  as it generally in deformed meta-morphic rocks.

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• Surface mining, accounting for 60 of US coal
  production, is usually utilized if coal seam
  (bed) is w/in 100 feet of surface. Surface
  mining allows for more complete coal removal, but
  is more disturbing to land surface, produces more
  rock waste water pollution. Organic rich
  shales assoc. with coal may also contain sulfur
  compounds (commonly minute grains of pyrite),
  which degrade easily upon exposure to water,
  producing sulfur acids. Acids may release other
  trace elements from shale debris. This provides
  major challenges to reclamation (p. 215).

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• Mountain-top removal is a very controver-sial
  form of surface mining (see pp. 214 216).
  Exempted from Surface Mining Control and
  Reclamation Act. 1999 and 2002 court decisions
  limited mountaintop removal because valley
  disposal of waste rock was burying streams in
  violation of the Clean Water Act.
• Underground mining is less disruptive, but is
  more expensive dangerous. Accounts for 40 of
  US production.

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• Concerns about burning coal
• Release of sulfur dioxide, nitrogen oxides,
  mercury, uranium, particulates, Disposal of ash
• Controversy exists as to the actual extent of
  acid rainfall related to coal burning. 10-year,
  540 million NAPAP study produced evidence that
  acidity of Northeastern US lakes was due to
  soil/vegetation condi-tions. Study attributed NC
  tree damage (Fig. 10.7) to insects. Conclusion
  was that acid precipitation was a nuisance, not a
  crisis. http//www.detnews.com/EDITPAGE/0004/03/ed
  it1/edit1.htm
• http//www.sepp.org/controv/epavskrug.html -
  NAPAP Study Info

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• Strategies for cleaning coal emissions
• Scrubbers, Fluidized-bed combustion, coal
  gasification, liquefaction (see pp. 217 218).
  Will likely remain an important energy source for
  power production, World has 200 year reserves at
  current use levels (p. 213).
• Oil Natural Gas 63 of US Energy Use, cleaner
  than coal, easier to transport. Drilling is
  generally a less disruptive method of retrieving
  energy from oil/ natural gas than coal mining
  methods.

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When oil companies drill deep wells,
expen-ditures may reach several million dollars
before well completion occurs. Large rigs like
this one can drill holes 30,000 feet deep.
Deepest US wells are generally gas wells in the
Anadarko Basin (SW Oklahoma).
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8,000 foot wells near Shattuck, OK take about
3 weeks (24/7) to drill. On Christmas Eve, 2002,
drilling continued during 110 F, blowing snow.
Technology improve-ments yield more successful
wells.
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• Among the improvements are directional
  drilling, allowing multiple wells per plat-form
  horizontal screen zone within pay zone oil
  reservoir more production.
• Other future improvements will allow deeper
  off-shore drilling on Gulf and Atlantic Coasts.
• In Late 1980s Wildcat well success was 10,
  now about 50. Wildcat wells are drilled more
  than ¼ mile from existing wells.

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Crude oil needs refinement before use,
primarily to separate different petroleum
products (see Fig. 10.10, p. 219). Differen-tial
boiling points used to separate frac-tions in
the fractionation tower. Some times greater heat
is used to crack larger molecules into smaller
molecules. Problems with US refinery system. No
new refineries since 1976, system running at 96
capacity, no slack in case 1 or more refineries
are out of commission. Regulations, lawsuits,
NIMBY philosophy make new refineries difficult to
build.
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• Factors affecting gasoline prices
• World crude oil prices Supply vs. Demand
• Concerns over terrorist threats to supplies
• Growth of China, India, US
• Taxes
• Regulations affecting gasoline blends
• Regulations affecting land access for drilling
• Weather issues affecting transport, off-loading
  of ships
• Conditions affecting refinery system

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• Future supplies
• Are We Running out of Oil?
• Gulf of Mexico Jack Prospect
• Canada's Oil Reserves
• America's Oil Shale Prospects
• The Case for ANWR Development
• Development considerations
• Constantly improving technology has greatly
  reduced the footprint of Arctic oil development.
  If Prudhoe Bay were built today, facility designs
  show the footprint would be 64 smaller.
• Prudhoe Bay gas reserves are 30.9 trillion cubic
  feet. No pipeline yet, being re-injected.

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Concerns over ANWR development are related to
past and present accidents. Exxon Valdez 1989
260,000 bbls, shallow water spill affected
shoreline shallow marine organisms. 1991 Gulf
War Iraq blew up 700 wells, deliberately
spilled 6,000,000 bbls into Persian Gulf. Other
Major Oil Spills
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• How Petroleum affects the Development of
  Alternative Energy Sources
• High Crude Oil/High Gasoline Prices Promote
  Conservation, Recycling of Lubricants,
  Development of Alternatives.
• Gradually rising prices may be accommo-dated by
  economy.
• A vibrant economy fosters innovation (new
  products, processes, energy sources, improvements
  in solar photovoltaics, battery technology,)
• Gasoline taxes do force conservation, but they
  hurt poor people the most, remove funds from the
  private sector, hurting the economy.

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