The Fossil Fuels: Natural Gas and Coal

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The Fossil FuelsNatural Gas and Coal
Lecture 5 HNRS 228 Energy and the Environment
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iClicker Question

• What is a typical drill depth for an oil well?
• A Several hundred feet
• B 1000 feet
• C Several thousand feet
• D All of the above
• E Only A and B above

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iClicker Question

• Which of the following is (are) used to confirm
  the presence of oil in a well?
• A Core samples
• B Well logging
• C Drill stem testing
• D All of the above
• E Only A and B above

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iClicker Question

• What is the name of the suspension used to keep
  fractures in rock open and allow oil to flow?
• A crackant
• B fracture suspension
• C flowant
• D fracturant
• E proppant

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iClicker Question

• The process by which components in a chemical
  mixture are separated according to their
  different boiling points, is called
• A Distillationism
• B Fractionation
• C Fractioning
• D Fractional distillation
• E Fractional fractionating

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iClicker Question

• Which of the following are not petroleum derived
  products?
• A gasoline
• B kerosene
• C jet fuel
• D plastics
• E None of the above

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Oil Exploration Summary

• Oil is trapped in rare geological structures
• Most of the oil in the world comes from a few
  large wells
• About one in ten exploratory drillings strike oil

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Overview of Natural Gas

• Supply of recoverable natural gas available at
  affordable costs has greatly increased over past
  10 years
• Industrys ability to produce natural gas from
  shales has gone from almost 0 to gt 20 of U.S.
  needs in just 10 years
• Natural gas demand is at 22-23 Tcf/year in the
  U.S. (historic highs). Increased availability of
  gas will allow demand to continue to grow over
  next several years

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1999 View of Natural Gas Supply

• N. American natural gas reserves found each year
  were replacing produced gas, but
• Industry needed to drill more and more wells just
  to hold reserves constant while demand for
  production was increasing
• Production from the Gulf of Mexico had peaked and
  was in decline
• The petroleum industry was starting to have
  success in producing gas from shale

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U.S. Reserve Base Trends Before and After Shale
Gas Production
Significant increase in gas reserves and
production from shales starts in 1999
Source EIA
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U.S. Natural Gas Production
3.7/yr
-1.9/yr
1.1/yr
U.S. natural gas production is at its highest
level ever in 2008
Source EIA
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Offshore Gulf of Mexico in Steep Decline
Production is down by almost 50 from 2001-07
Source EIA
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Enter Barnett Shale

• Barnett Shale
• Geological formation located in the Bend
  Arch-Fort Worth Basin of Texas
• Consists of sedimentary rocks of Mississippian
  age (354323 million years ago)
• Formation underlies the city of Fort Worth and
  underlies 5,000 square miles (13,000 km2) and at
  least 17 counties of Texas

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Barnett Shale Daily Production
(TX RR Commission Areas 5 9 only)
Percentage of U.S. natural gas demand supplied by
Barnett Shale only
While supply from offshore GoM has fallen by gt6
bcf / day, Barnett Shale production has grown by
gt 4 bcf/d
Source TX RR Commission
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What Has Changed to Allow us to Produce This Gas?

• Techniques to allow horizontal wells to be
  drilled efficiently have greatly improved
• In 4Q 06, Barnett wells drilled in 25 days for
  161/ft
• In 2Q 08, Barnett wells drilled in 19 days for
  131/ft
• This is 24 faster and 19 cheaper

Source Simmons
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Fracd (Fracturing) Wells
Barnett shale is very hard, and it was virtually
impossible to produce gas in commercial
quantities from this formation until recent
improvements were made in hydraulic fracturing
technology and horizontal drilling, and there was
an upturn in the natural gas price.
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What Has Changed to Allow us to Produce this Gas

• Ability to drill longer laterals
• Experimentation on Completion Methods
• Cemented/Uncemented liners
• Staged Fracing
• Simulfracs
• Frac fluids and proppants

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What Has Changed to Allow us to Produce This Gas?

• Ability to fracture shales and significantly
  increase production per well has dramatically
  improved
• In 2005, the median initial production rate
  Barnett Shale wells in Johnson County, TX was 2.2
  MMcf /day
• In 2008, the median initial production rate for
  the Barnett wells in the same county was 7.0
  MMcf/day

Source IHS
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What Has Changed to Allow us to Produce This Gas?

• Combining drilling production efficiencies
• One rig in 2005 could drill 9 wells at 2 bcf/well
  
• Versus
• One rig in 2008 can drill 12 wells at 4.5
  bcf/well
• In 2005, the rig added 18 bcf of reserves
• In 2008, the rig adds 54 bcf of reserves

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Conventional Well vs. Shale Gas Well Production
Curves
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Basins Where Additional Gas Will Be Produced From
Shales
Marcellus
Woodford
Haynesville
Barnett
Estimated Gas In-Place in these Shales is 2000
Tcf
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Todays Relative Share of Energy Market by Fuel
Source EIA Annual Energy Outlook 2009
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U.S. Energy Demand by Fuel
History
Projections
Renewables
Biofuels
Liquids
Quadrillion Btus
Natural Gas
Nuclear
Coal
Source EIA Annual Energy Outlook 2009
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Natural Gas Use by Sector in 2008
29 Electricity Generation
21 Residential
Electricity generation from natural gas has grown
at rate of 4/year since 1990
14 Commercial
3 Transportation
33 Industrial
Industrial usage of natural gas has fallen at
rate of 2/year since 1998
Source EIA Annual Energy Outlook 2009
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Todays Relative Share of Electricity Generation
by Fuel
Other Renewables 3
Hydro 6
Nuclear 20
Coal 49
Natural Gas 21
Oil 1
Source EIA Electric Power Monthly, April 2009
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Natural Gas Supply thru 2030
Alaska
Source EIA Annual Energy Outlook 2009
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History U.S. Natural Gas Production
Consumption
Source EIA
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Supply vs. Demand thru 2015
Available supply Assume 1.8 growth / year in
production capacity (starting in 2010) and net
imports at 3 Tcf/yr vs. 3.3-4.0 Tcf/yr seen since
01
Demand (dashed curve) Assume 4 growth in use of
gas for electricity generation after 1 year, 3
reduction in overall demand for 2009
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Natural Gas is Cleaner
Relative Level of NOx Emissions
Source South Coast Air Quality Management
District 2007 Air Quality Management Plan Summit
Panel
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Natural Gas is a Low Carbon Fuel
Pounds of Carbon per Billion BTU
Source EIA, Natural Gas Issues Trends, 1998
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Overall Economics of fuels before carbon tax
/KWh
Source SDI research team analysis
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Distribution of natural gas

• Impractical to ship must route by pipe
• 1.3 million miles of pipe (250,000 miles of
  mains)

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Natural Gas

• Extracted as oil-drilling byproduct
• was once burned off at well head as means of
  disposal
• Mostly methane, some ethane, and a little
  propane, butane
• 2 times cheaper than electricity per energy
  content, comparable gasoline per joule
• this is recent in 2004, it was 3.5 times cheaper
  than electricity, 3 times cheaper than gas
• Well-suited to on-the-spot heat generation water
  heaters, furnaces, stoves/ovens, clothes dryers
• more efficient than using fossil-fuel-generated
  electricity

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Summary of Natural Gas

• U.S. has a very large natural gas resource base
  remaining to be produced, and
• The petroleum industry has greatly improved its
  ability to produce gas from shales, so
• We believe supply capacity will be able to meet
  growing demand w/o significant cost increases
  unless government imposes onerous taxes and
  additional regulation.

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How much do we use, and where do we get it?

• In 2003, we used 21.8 tcf (Tera-cubic feet, or
  1012ft3) about 23 QBtu (23 of total)
• Out of the 21.8 tcf used, 88 was domestic
• 11.8 from Canada
• 0.08 from Algeria (shipped in liquefied form)
• 0.03 from Mexico
• Have used about 1,100 tcf to date

Q
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How much do we have left?

• Estimated recoverable amount 871 tcf
• 40 years at current rate
• Estimates like this do account for future
  discoveries
• present proven reserves provide only 8 years
  worth

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Recollecting Chemistry
kJ per gram

• All fossil fuels are essentially hydrocarbons,
  except coal, which is mostly just carbon
• Natural Gas is composed of the lighter
  hydrocarbons (methane through pentane)
• Gasoline is hexane (C6) through C12
• Lubricants are C16 and up

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Hydrocarbon Reactions

• Methane reaction
• CH4 2O2 ? CO2 2H2O energy
• 1 g 4 g 2.75 g 2.25 g 55 kJ
• Octane reaction
• 2C8H18 25O2 ? 16CO2 18H2O energy
• 1 g 3.51 g 3.09 g 1.42 g 48 kJ
• For every pound of fuel you burn, you get about
  three times that in CO2
• one gallon of gasoline ? 22 pounds of CO2
• occupies about 5 cubic meters (1300 gallons) of
  space

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Aside Carbohydrate Reactions

• Typical carbohydrate (sugar) has molecular
  structure like CH2ON, where N is some integer
• refer to this as unit block C6H12O6 has N6
• Carbohydrate reaction
• CH2ON NO2 ? NCO2 NH2O energy
• 1 g 1.07 g 1.47 g 0.6 g 17 kJ
• Less energy than hydrocarbons because one oxygen
  already on board (half-reacted already)
• For every pound of food you eat you exhale 1.5
  lbs CO2

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Coal

• Coal is a nasty fuel that we seem to have a lot
  of
• Primarily carbon, but some volatiles (CO, CH4)
• Reaction is essentially C O2 ? CO2 energy
• Energy content varies depending on quality of
  coal, ranging from 47 Cal/g
• Highly undesirable because of large amounts of
  ash, sulphur dioxide, arsenic, and other
  pollutants
• Also ugly to remove from the ground

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Coal types and composition
kJ/g
Natural Graphite
fixed carbon
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ash
Anthracite
29
Bituminous
35
Bituminous
31
sub- bituminous
27
Lignite
25
moisture content
Peat
21
volatile matter
Wood
20
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Use of Coal

• 88 of the coal used in the U.S. makes steam for
  electricity generation
• 7.7 is used for industry and transportation
• 3.5 used in steel production
• 0.6 used for residential and commercial purposes
• 0.1 used on Halloween for trick-or-treaters
  ltchucklegt

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Estimated Worldwide Coal Reserves
Country Amount (109 tonne) Percentage of Total
United States 250 25
Russia 230 23
Europe 138 14
China 115 12
Australia 82 8.3
Africa 55 5.6
South America 22 2.2
North America 7.7 0.8
Total 984 100
1st edition of book had U.S. at 1500 billion
tons. What happened to all that coal? 1st
edition of book had Russian coal at 4300 billion
tons. Gross overestimates?
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U.S. Coal Production History
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When will coal run out?

• We use 109 tonnes of coal per year, so the U.S.
  supply alone could last as long as 250 (1500)
  years at current rate
• Using variable rate model, more like 75100
  (400600) years
• especially relevant if oil, gas are gone
• This assumes global warming doesnt end up
  banning the use of coal
• Environmental concerns over extraction also
  relevant

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Shale Oil

• Possibly 6002000 billion barrels of oil in U.S.
  shale deposits
• compare to total U.S. oil supply of 230 billion
  bbl
• Economically viable portion may only be 80
  billion bbl
• 8 times less energy density than coal
• lots of waste rock large-scale disposal problem
• Maximum rate of extraction may be only 5 of our
  current rate of oil consumption
• limited by water availability

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Tar Sands

• Sand impregnated with viscous tar-like sludge
• Huge deposit in Alberta, Canada
• 300 billion bbl possibly economically recoverable
• It takes two tons of sands to create one barrel
  of oil
• energy density similar to that of shale oil
• In 2003, 1 million bbl/day produced
• grand hopes for 5 Mbbl/day or 6 of world oil
  production
• 2002 production cost was 20 per barrel, so
  economically competitive

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In Class Question for Group Discussion

• Over the weekend (4 Feb 6 Feb) there was a
  political pundit talk show on television. At one
  point, the moderator of the show asks the panel
  about the current weather storms (especially snow
  storms in USA and cyclone in Australia) and if
  they may be a result of global warming. The
  moderator quotes Al Gore about the reason that
  these weather patterns may be indicators of
  global warming. One of the pundits response was
  that Al Gore would link anything bad to global
  warming. Discuss in your groups these matters.
  Address two questions in your responses
• How is the moderator question itself flawed?
• How may global warming and low pressure storm
  intensity be causally linked?