formation process derived from aquatic organisms, mainly phytoplankton and zooplankton-lived...
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Formation Process Derived from aquatic organisms,
mainly phytoplankton and zooplankton-lived millions of years ago in shallow waters
Buried through sedimentation (depositing particles)->cut off from oxygen
Formation Cont.
Form into an organic material know as kerogen Insoluble organic material that is the
main precursor for crude oil and natural gas
Temperature and pressure determine type of fossil fuel: crude oil or natural gas Natural gas- 2,500 meters from surface
Crude Oil
60°C to 150°C, depth of 1,500-4,500 meters “Oil Window”- where most kerogen is
converted into crude oil Molecule made up of relatively long
chains of carbon containing up to about 20 atoms
Shortening chains reduced viscosity->flows toward surface->carrier beds Can sometimes seep to the surface Ex: La Brea tar pits in LA
Impermeable rock layer can trap the crude oil or natural gas->fills the spaces in the grains of the sedimentary rock->reservoirs
Oil Facts Most oil is contained in a few giant oil
fields In the US, the largest 81 fields contain
about 40% of the oil that is known to exist in over 14,000 oil fields.
About half of the worlds oil supply exists in the Arabian-Iranian province
Discovery of Oil
Only sedimentary rocks contain crude oil and natural gas
Must occur with some trapping structure
Greatest potential for oil=overlay areas that have/once had high rates of net primary production
Large Oil Fields
1. Off Coasts of Louisiana and Texas- highly productive estuaries
Large Oil Fields2. Middle East- once part of highly
productive shallow inland seas
Discovery Cont.
Early wells- drilled near surface-no geologic structure to trap the migrating oil
Subsurface structures- maps produced using seismic equipment Shoots sound waves below surface and
listens for echoes
Oil Detection
Detection Cont.
Maps have been improved by 3D seismic technology Using rectangular grid of detectors
rather than single line of detectors Improves resolution-> can identify small
features likely to contain crude oil or natural gas
Extraction Must be brought to the surface Not a pool of free flowing oil Oil field is similar to a oil soaked brick
Extraction Cont.
• Oil, gas, and water exist in 3 layers within sedimentary rock
• Natural gas=least dense=top• Oil=middle layer=floating on more dense water layer
Micro Level
Within oil layer: Oil exists in droplets suspended within the
water that coats the pores walls Natural gas dissolved within oil droplets
Available Oil
• Amount that can be recovered depends on:
1.Field Density– High D=little space between particles=low oil
2.Permeability– High permeability=increase rate of oil flow to
surface– Increases with size of pores and pressure
3.Porosity– Space between particles that can store oil– Higher porosity=more space for oil
Primary Recovery Oil pushed to surface by pressure
gradient When first drilled, field pressure is MUCH
higher than atmospheric pressure->forces oil to surface
Also forced upward by natural gas bubbling out of oil: like carbonation pushes soda out of bottle when first opened
Primary Recovery Cont.
Least expensive Recovers about 10% of the oil
Secondary Recovery As oil moves to surface, pressure
gradient decreases Can increase production by
repressurizing Drill injection well near original->inject
water, steam or CO2 into field Recovers another 10-30% of oil in field
Tertiary Methods
Secondary methods will lose efficiency->water makes paths that bypass oil
Tertiary methods= inject heat or materials that will decrease viscosity->easier to flow
Recovery another 20% of oil in field Primary+Secondary+Tertiary=30-
60% of oil
Oil Refining
Crude oil cannot be used directly by society Long carbon chains->more viscous-
>less energy Refining-breaks and separates the
long chain of carbon molecules into shorter chains Called refined petroleum products
Refining Cont.
Crude oil is heated->shorter chains evaporate and condense at different heights in column Bottom barrel- asphalt & residual fuel oil Top- jet fuel & motor gasoline(8-12 C
molecules) 8 carbon atoms=octane Regular gas (least expensive)- octane 87 Premium (more expensive)- octane 92 or
93
Heavy vs. Light Crude Oil Long, heavy chains-less desirable-
generate large fraction of bottom-of-the-barrel products Mexico- Maya Crude Oil
Short, light chains-more desirable-large fraction of top-of-the-barrel production Saudi Arabia- Saudi Light Crude Oil
Reserves to Production Ratio (R:P) Measures the quantity of oil in
proved reserves relative to the current rate of oil production Ex: 10:1= proved reserves can satisfy
current rate for demand for 10 years Does NOT imply that oil supplies will run
out in 10 yrs.
US- has remained fairly constant over the last 50 years
Yield per Effort
Measures the barrels of oil found per foot of well drilled
Zapp hypothesis- assumed that the average would remain constant over the next 4 billion feet Based on that, early 1960’s, USGS
forecast that 590 billion barrels of oil would be found and produced in the lower 48 states (little to no drilling in Alaska at this time)
Yield per Effort Cont.
Best first principle- assumptions made by USGS probably incorrect…best first was right!
Yield per effort declines as more wells are drilled First fields found tend to be largest After drilling in larger fields, wells are
drilled in smaller fields and yield per effort declines
M. King Hubbert
• Petroleum geologist->worked for Shell Oil Company
• Using best first principle, fit the yield per effort data to an exponential decline curve
Hubbert Curve
Estimated that about 170 billion barrels of oil would be found in the lower 48 states
Recent analysis confirm the exponential decline in yield per effort Also depends on the rate at which wells
are drilled and prices of oil/natural gas
When will we run out???
As world depletes oil, production will decline
Hubbert forecasted that the peak of oil in US would be in 1970, and a total of 170 billion barrels would be recovered….he was CORRECT
When will we run out??
Peak World oil has been attempted to be forecast, but has been incorrect (probably due to changes in oil prices and production decisions by OPEC).
Many believe the peak will be in the next 10 to 20 years Will cause prices to increase
Impact of Declining Oil on Economy Important for agriculture: need for
increase food supply depends on fertilizer Fertilizer->made from natural gas Irrigation->delivered by pumps powered
by deisel
Impact on Economy Cont.
EROI for oil production parallels changes in production EROI increases as production increases
towards its peak After peak, EROI declines
Means that more and more energy is required to produce each barrel->less energy remains to power non-energy sectors (standard of living)
Impact on Economy Cont.
Decline in EROI implies that the end of oil may occur before the wells go dry EROI will be 1:1->one Btu of energy is
required to produce one Btu of oil
Alternative Energy
Need to transition to alternative energy sources
Alternative energy sources have lower EROI’s than oil and gas
Reductions in amount of energy lets over for non-energy sectors can be avoided if investments to alternative sources happened before peak world oil
Should the US Reduce its Dependency on Imported Oil? US has been a net importer of oil
since 1947 Would be better for national security
and economy if US could reduce or eliminate imports. Esp. for unstable nations or nations with
a different political agenda->Iran, Saudi Arabia, or Venezuela
Oil Dependency World oil market- like “one big pool
of oil” Any disruption “ripples” and affects
everyone Example: US imports all oil from Canada
& Saudi Arabia stops all oil exports->Saudi Arabia's old oil customers look for another oil exporting country->all oil prices to go up
Should US Change Dependency? Any effort to change the pattern of
US oil imports would most likely increase prices for US customers Due to the market matching supply and
demand in a way that minimizes the $ of transporting oil
EX: Oil drilled/produced in Alaska is exported overseas instead of being shipped to refineries on U.S. West Coast
Should US be Self-Sufficient?? NO!!!!
It is less expensive to import oil from overseas than it would be to replace oil with domestic production
http://www.ted.com/talks/garth_lenz_images_of_beauty_and_devastation.html
Arctic National Wildlife Refuge 19 million acres: largest land-based
unit of the National Wildlife Refuge System
Located in Alaska Established in 1960 and expanded in
1980
Drilling for Oil in the Arctic National Refuge 1.5 million acres coastal plain Signs of significant quantity of oil Most optimistic scenario-> 2 million
barrels/day produced 20 years AFTER drilling begins
BP Oil Spill
Running weeks behind and tens of millions of dollar over budget to complete Macondo well in Gulf of Mexico
April 20, 2010 Failure of the cement at the base of
the 18,000-foot-deep well that was supposed to contain oil and gas within the well bore
BP Oil Well Explosion
BP Spill Cont. Eleven people killed and
approximately 17 injured. A blowout preventer, intended to
prevent release of crude oil, failed to activate.
The BP Oil Spill is the biggest in American history, with between 17 and 39 million gallons spilled in the Gulf of Mexico
BP Clean-up Over 30,000 people responded to the
spill in the Gulf Coast working to collect oil, clean up beaches, taking care of animals and performing various other duties.
Responders used 5.5 million feet of boom, a barrier placed in water, to collect and absorb oil
BP Clean-up
One method of treating the oil spill is "in-situ burning" or burning oil in a contained area on the surface of the water. Oil spills are bad, but burning is also bad for the environment.
16,000 total miles of coastline have been affected, including the coasts of Texas, Louisiana, Mississippi, Alabama, Florida.
Over 1,000 animals (birds, turtles, mammals) have been reported dead, including many already on the endangered species list. Of the animals affected by the spill that are still alive only about 6% have been reported cleaned, but many biologists and other scientists predict they will die too.
BP Clean-up Cont.
BP made a deal with the government that they would set aside $20 billion toward oil cleanup and spill victims.
President Obama announced that his administration would create a $20 billion spill response fund.
Continuing Issues
Even though the gushing well was capped in July 2010, oil is still washing up on shores, which might do long-term damages to humans affected.