Petroleum Resources

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Petroleum Resources

• Lecture 14
• GLY 120

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Oil (Petroleum)

• Composed of hydrocarbons
• organic molecules composed of chains of hydrogen
  (H) and carbon (C)
  
• Hydrocarbons can be
• long chains (polymers) of C (solid - tar)...
• to smaller carbon chains (thick lubricating oil
  to light oil, gasoline)...
  
• to single molecules (natural gas - methane - CH4).

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• Heavy oil, light oil, and natural gas represent
  increasing grades of petroleum, formed with
  increasing temperature during burial (affects
  oil/gas ratio)
• Diagenesis 0-100 m depth,
• Catagenesis 100 m to 3.5-5.0 km depth, 50-150C
• Metagenesis 3.5 km depth, 150C

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• Oil window
• 3.5-6.2 km
• 90-150?C
• Gas window
• 6.2-9 km
• 150-225?C

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Petroleum as a resource

• Derived from crude oil
• Separation and isolation of different compounds
  Refining
  
• distillation, fractionation, thermal cracking

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Products made from petroleum
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Formation of Petroleum

• Accumulation and preservation of plankton as an
  organic-rich mud.
  
• Buried by many overlying layers and heated by
  burial
  
• Conversion of organic matter to oil (takes
  millions of years).

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• To form an economic deposit, the following are
  needed
  
• A source rock
• The rock formed by the organic matter
• Migration of the petroleum upwards through the
  overlying rock
  
• Reservoir rock
• The rock in which the petroleum migrates into
• Trap
• Some structure that will trap the petroleum and
  not allow it to migrate all the way to the surface

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To form an economic oil deposit

• Source Rock
• oil shale - sedimentary rock formed by compaction
  of organic-rich mud, buried and heated
  
• Migration
• Petroleum has a lower density than the rocks
  overlying it
  
• Allows it to move toward the surface

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To form an economic oil deposit

• Reservoir Rock
• Porous and permeable rock
• Hold oil/gas in pore spaces
• Common reservoir rocks
• Sandstone
• Fractured limestone
• Often trapped by impermeable layers, geologic
  structures

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Petroleum Traps (cap rock, trap rock)

• Impermeable rock layer or structural feature that
  prevents oil from migrating any further.
  
• Petroleum accumulates in the reservoir rock
• Kept in place by the trap.
• Common types of traps
• Fold trap
• Fault trap
• Stratigraphic trap
• Salt domes

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• Fold trap
• also called an anticlinal trap
• folded strata with an impermeable layer on top of
  a permeable layer
  

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• Fault trap
• where the movement along a fault brings a
  permeable layer up against an impermeable layer
  

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• Stratigraphic trap
• traps that result when the reservoir bed is
  sealed
  
• by other beds
• or by a change in porosity or permeability within
  the reservoir bed itself
  

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• Salt domes
• the salt dome is impermeable
• petroleum can get trapped up against it

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World Supply and Demand

• Where is the oil?
• About 2/3 of the world's oil is located in the
  Middle East.
  
• Other important reserves include
• Gulf of Mexico
• Venezuela
• West Siberia
• Libya
• Nigeria

Regions of major known oil reserves
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• USA 3 of the world's oil reserves
• needs to import 1/2 of its oil (cost 25
  billion)
  
• In 2007
• 4.9 billion barrels imported
• 58.2 of oil imported
• 46 from OPEC countries (16 from the Persian
  Gulf)
  
• Top oil suppliers to the US Canada, Saudi
  Arabia, Venezuela, Mexico
  
• Projections 62 of oil imported by 2020

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U.S. Oil

• As of Dec 31, 2007, the US had 20.97 billion
  barrels of proven oil reserves
  
• 11th highest in the world
• Approx. 77 in the following areas
• TX (24)
• Gulf of Mexico (14)
• AK (22)
• CA (17)
• 21 decline since 1990

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• We must rely on Middle East countries for our
  oil, and these countries are often politically
  unstable oil crises
  
• 1967 Six Day War
• Israel makes preemptive strike on Egypt in Sinai
  in response to build-up by Egypt, Syria, and
  Jordan which were preparing an attack.
  
• Israel takes Sinai from Egypt, Jerusalem and West
  Bank from Jordan, and Golan Heights from Syria
  
• In retaliation for U.S. support of Israel, OPEC
  places an embargo on oil exports to U.S. and the
  Suez Canal is closed

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• 1973 - OPEC oil embargo
• OPEC stopped exports to the US and other western
  nations
  
• They meant to punish the western nations that
  supported Israel in the Yom Kippur War
  
• The Yom Kippur War was fought from October 6 to
  October 26, 1973, between Israel and a coalition
  of Arab nations led by Egypt and Syria
  
• One of the many results of the embargo was higher
  oil prices all throughout the western world,
  particularly in America.
  
• Oil prices quadrupled from 25 to 1 in just
  a few months in America

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• September 1980-August 1988 Iran-Iraq War
• Iraq invaded Iran
• The US got involved after the Iranians stepped up
  their attacks on oil shipping in the Gulf
  
• The US agreed to reflag Kuwaiti tankers with
  American flags and provide them with a US naval
  escort
  
• The war altered regional and even global
  politics, and led to the 1990 Iraqi invasion of
  Kuwait
  

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• August 1990 Iraq invades Kuwait
• Iraqi forces occupied Kuwait and positioned
  themselves for an assault on Saudi Arabia
  
• It was feared that Iraqi control of both Kuwait
  and Saudi oil fields would pose an intolerable
  threat to Western economic security
  
• Pres. Bush (41) quickly decided on a tough
  military response to defend Saudi Arabia and
  drive the Iraqis out of Kuwait
  
• 2003 Iraq War??

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How long will it last?

• The world's oil supply (currently estimated at 1
  trillion barrels) is projected to last several
  decades (60 years) until little oil remains
  
• Increased reliance on
• alternative sources of fuel (electric, solar,
  etc.)
  
• new technologies - hybrid cars (gas electric)
• However, companies keep finding new oil fields,
  thus extending our supplies.

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Arctic National Wildlife Refuge
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• Estimated yield? 4.3-11.8 billion barrels of
  technically recoverable oil
  
• Estimated effect on U.S. imports?
• U.S. consumes 20 million barrels/day
• 1.3 year supply IF the US gets all of the oil
  that is there
  
• Once the oil enters into the oil companys
  pipeline, it belongs to the oil company
  
• Estimated environmental damage?
• Sanctuary for polar bears, musk oxen, caribou,
  migratory birds
  
• Raise fuel mileage standards instead

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Merits of Oil as an Energy Resource

• Disadvantages -
• limited supply, US dependence on imports
• pollution - oil spills, pipeline damage to
  environment, air
  
• brines produced must be disposed
• source of CO2 - greenhouse gas

• Advantages
• easy to handle (liquid form)
• extremely versatile and many uses
• relatively inexpensive and technology exists for
  its use

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Exxon Valdez
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• On March 24, 1989, The Exxon Valdez grounded on
  Bligh Reef, and spilled nearly 11 million gallons
  of oil into the biologically rich waters of
  Prince William Sound, Alaska
• Approximately 1,300 miles of shoreline were
  impacted by the oil

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• Impact on wildlife
• Estimated number of animals that died
• 250,000 seabirds
• 2,800 otters
• 300 harbor seals
• 250 bald eagles
• Up to 22 killer whales
• Billions of salmon and herring eggs

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Oil sheen on the surface of Prince William Sound
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Oil-covered shoreline
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Oil-covered otter
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Oil-covered seabird
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• A survey done in 2001 by NOAA found that a total
  area of 20 acres of shoreline in Prince William
  Sound is still contaminated with oil
  
• In the aftermath of the Exxon Valdez incident,
  Congress passed the Oil Pollution Act of 1990
  
• Required the Coast Guard to strengthen its
  regulations on oil tank vessels and oil tank
  owners and operators

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More Petroleum Resources
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Natural gas methane (CH4)

• Has merits similar to liquid petroleum except it
  is a much cleaner fuel - CO2 H2O produced.
  
• Also produces the lowest amount of CO2 of all
  fossil fuels.
  
• Expensive transport
• If it cannot be economically transported it is
  burned as a waste product
  
• Current estimates natural gas supplies will last
  until 2110.

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Other fossil fuels

• Tar sands sands (or sandstone and limestone)
  that contain heavy oil (too viscous to migrate at
  normal temperatures).
  
• Strip mine if near the surface, steam used to
  extract oil.
  
• Canada has a considerable resource of tar sands,
  the US has smaller amounts.
  
• They have similar advantages as oil, but they are
  more expensive to mine and involve large strip
  mine operations.
  
• Limited in supply

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Tar sand
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• Oil Shale
• Fine-grained sedimentary rock containing kerogen
  
  
• waxy organic solid
• remains of plants, algae, and bacteria
• Rock must be crushed and heated to 500 C to
  liberate hydrocarbons.
  

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Oil shale