Chapter 7 Fundamentals of Energy Fossil Fuels and Nuclear Energy
Mar 31, 2015
Oil and Natural GasPetroleum or crude oil, is not a single chemical compound
Liquid petroleum, or oil, comprises a variety of liquid hydrocarbon compounds, which are made up of long molecular strings of carbon and hydrogen
There are also a variety of gaseous hydrocarbons, collectively called natural gas, of which the compound methane (CH4) is the most common
How is Petroleum Created? Most geologists believe that crude oil and natural gas are the product of compression and heating of ancient organic materials over long geological time
According to this theory, oil is formed from the preserved remains of prehistoric zooplankton and algae which have settled to the ocean bottom and are buried in large quantities under anaerobic conditions (no oxygen)
How is Petroleum Created? Over geological time this organic matter, mixed with mud, is buried under heavy layers of sediment
As burial continues, the pressure and the temperature both increase, and chemical changes begin to occur
The large, complex organic molecules are slowly broken down into long chains of hydrocarbon molecules, which have the consistency of asphalt
How is Petroleum Created? Specifically, the organic molecules change into a waxy material known as kerogen
With time and if the kerogen is subjected to increased pressure and heat, it is further changed into liquid and gaseous hydrocarbons in a process known as catagenesis
How is Petroleum Created?
A Texas Oilman would say, the petroleum “matures”
It successively changing from “heavy” long hydrocarbon molecules into “light” simple gas and oil molecules
The thick liquids become progressively thinner and more valuable or “sweeter” because it requires less processing at the oil refinery
How is Petroleum Created?
Most of the maturation process occurs between 50o to 100o C (120o to 210o F)
At higher temperatures the hydrocarbon converts to methane gas
The Time Factor
The amount of time it takes to create petroleum is not precisely known
However, petroleum is not found in rock that is younger than 1 or 2 million years old
So, this is a slow process which takes million of years
This means that we are using up oil much much faster than it can be replaced by nature
We have essentially a finite supply of oil, then it will be gone
Oil and Gas Migration
We want to extract the oil
But the majority of the petroleum source rocks are fine-grained sedimentary rocks of low permeability
The petroleum is spread throughout the rock and it is hard and uneconomical to extract large quantities of oil or gas quickly
Oil and Gas Migration
To become economical, two things need to happen:
The gas and/or oil must migrate out of the source rocks into more permeable rocks, which is called the reservoir rock
And eventually, a large quantity must become concentrated and confined into a petroleum trap beneath an impermeable layer called a cap rock
Types of Petroleum Traps
(A) A simple fold trap (B) fossilized coral reef (C) fault trap (D) salt dome
Hydrocarbon Uses
A given oil field may contain a variety of hydrocarbon compounds and these different compounds have different uses
Oil, gas and methane can all be found together
Enhanced Oil Recovery
Some of the first oils wells were gushers, where the oil behaved like water in an artesian well
Extracting oil using no techniques beyond pumping is called primary recovery
This will only remove part of the oil deposit, usually a third or much less
However, on the average, two-thirds of the oil is left in the ground
There are many secondary recovery techniques that allow addition oil to be extracted
When flow falls off, water can be pumped into the reservoir rock, filling empty pore space and buoying up more oil
Or you can pump in steam
Or explosives can be set off in the oil zone, fracturing the rock and increasing permeability
Or carbon dioxide gas can be pumped in
Enhanced Oil Recovery
Secondary recovery can allow up to an additional 40% of the known oil reserves to be extracted
All of these secondary recovery methods add to the cost of oil extraction
Enhanced Oil Recovery
U.S. Energy Consumption The U.S. produces a staggering amount of energy per year, and about 80% of that energy currently comes from the fossil fuels coal, natural gas and oil
U.S. Energy Consumption The U.S. is the number one consumer of energy in the world and that consumption is rising
We now use 100 quadrillion of BTUs per year
BTU
In the United States, the term BTU (British Thermal Unit) is used to describe the energy content of fuels
A BTU is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit
143 BTU is required to melt a pound of ice
BTU One quadrillion BTU is:
1,000,000,000,000,000 BTU
That is a 1 followed by 15 zeros
It would take over 31 million years to count to a quadrillion at the rate of one number per second
But we are talking about 100 quadrillion
Supply and Demand
Oil is commonly discussed in quantities of barrels, where one barrel equal 42 gallons
Worldwide, over 500 billion barrels of oil has been consumed
Unfortunately, half of that consumption occurred over the past 25 years
The estimated proven oil reserves are about 1 trillion barrels
Or about 50 years at the current rate of use
Proven World Oil Reserves 2008Crude oil reserves in billions of barrels as of June 2008
Note that the Middle East has more oil than the entire rest of the world combined
Major World UsersLike other resources, petroleum sources are very unevenly spread around the world
For example, high-tech, densely-populated Japan has no oil, and must import 100% of the oil it needs
Imported oilMore than half of the oil consumed by the U.S. has been imported
Principle sources were Saudi Arabia, Venezuela, Canada and Mexico
Imported oilIn 1973, the U.S. dependence on foreign oil became a major political and strategic military concern, when OPEC shut off oil supplies
OPECThe Organization of Petroleum Exporting Countries (OPEC) is a cartel of twelve countries made up of Algeria, Angola, Ecuador, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the United Arab Emirates and Venezuela
OPECOPEC nations control two-thirds of the world's oil reserves and currently produce 36% of the world's oil, affording them considerable control over the global market
Strategic Petroleum Reserve
The Strategic Petroleum Reserve was established in 1977 to store about 550 million barrels of oil for military & emergency use
This was equal to a 115 day supply for 1977
Strategic Petroleum Reserve
As of January 22, 2009, the current inventory was 702.8 million barrels
This equates to 33 days of oil at current daily US consumption levels of 21 million barrels a day
U.S. Oil Supplies
The U.S. originally had about 10% of all the world’s oil supply
The U.S. has consumed over 200 billion barrels of oil
U.S. Oil Supplies
We currently consume about 7 billion barrels a year
For the past three decades we have been discovering new oil in the U.S. as fast as we were consuming
But...
Declining Yields
For land or offshore, the average yield from producing wells in the U.S. is declining, from a peak of 18.6 barrels per well per day in 1972 to 10.9 barrels in 2000
Declining YieldsThe total daily amount of oil produced in the U.S. has been steadily declining and is predicted to continue to decline
Hubbert’s Peak
M. King Hubbert was an oil man who predicted in 1956 that oil production would follow a bell curve
He was ostracized by the entire oil industry
The main counter argument was that we were just beginning to use modern exploratory methods and we simply had no idea how much oil existed on Earth
The “sky was not falling!”
Future Oil Prospects
Many people think that as oil prices soar, there will be increased exploration and discovery of new reserves
There is a finite amount of petroleum in the ground and we have found most of it
Two-thirds of new exploratory wells come up dry
The days of the gushers are over
Future Oil ProspectsIt is now very expensive to drill an exploratory oil well on land
It cost typically $2 to $20 million dollars per well
Future Oil ProspectsThe costs for drilling offshore are substantially higher, easily over $100 million and up
Drilling oils wells in the deep, abyssal plains of the open ocean may cost billions per well
U.S. Natural Gas UseThe supply and demand picture for natural gas is similar to that for oil
Natural gas provides about 25% of the energy used in the U.S.
Until recently, it was believed that the U.S. has 200 trillion cubic feet of proven reserves
And we import 15% of our natural gas
Natural Gas Reserves 2008The Western Hemisphere, especially the United States, contains substantial proven reserves of natural gas
Very Deep Natural Gas
At these depths, all petroleum molecules have been broken down into natural gas
The gas is under tremendously high pressure and is typically dissolved into fluids such as saline brines
The gas occurs in “oil shale”
Deep exploratory wells have recently discovered that tremendous natural gas reserves exist at depths of several thousand feet
Oil ShaleOil shale is a generic name for rock that contains petroleum
Oil shale is a misnomer
The rock does not have be shale, it can be any of a variety of sedimentary rocks, such as sandstone or limestone
There is actually so little oil in oil shale that it is useless
Rather, the potential fuel in oil shale is natural gas
Distribution of Oil Shale The U.S. has what is believed to be the second largest known oil shale deposits in the entire world (China may be first)
In the long run, this could provide a staggering amount of natural gas
Marcellus Shale The Marcellus Shale is a type of oil shale that is found through out the Eastern United States along the Appalachian Mountain range
It is estimated to contain 500 trillion cubic feet of natural gas
This could meet U.S. energy needs for a very long time
One of the extraction problems is that the Marcellus Shale ranges from 3000 to 9000 feet in depth below the surface
Marcellus Shale
FrackingRecent advances in horizontal drilling techniques and hydraulic fracturing (called fracking) have made removing natural gas from the Marcellus Shale both possible and economic
Ban Hydraulic Fracturing
Facebook.com “Arguments against hydraulic fracturing center around the extent to which fracturing fluid used far below the earth's surface might pollute fresh water zones, contaminate surface or near-surface water supplies, impact rock shelf causing seismic events or lead to surface subsidence...”
UT & Fracking
News Sentinel [Dec. 2, 2012] “The University of Tennessee plans to drill for natural gas in its research forest in Morgan and Scott counties, a proposal that would allow UT to lease its land to an oil and gas company and the study the environmental impacts of hydraulic fracturing...”
U.S. Natural Gas Reserves
In the past four years, the United States has increased its production of natural gas by 27%
By 2020, the United States is expected to be the number one producer of natural gas in the entire world
Burning Ice
Methane clathrate, also called methane hydrate or methane ice, is a solid form of water that contains a large amount of methane trapped within its crystal structure
Burning IceAbout 10 years ago, it was discovered that extremely large deposits of methane clathrate occur under sediments on the ocean floors, usually along the coastlines
Burning Ice
The size of these oceanic deposits is staggering
For example, it has been estimated that over 1 quadrillion cubic feet of methane ice lies offshore of North and South Carolina alone
There is more methane ice than all other fossil fuels combined
Burning Ice
Methane is a far more efficient greenhouse gas than carbon dioxide
The amount of methane locked in methane hydrates is estimated to be 3000 times more than is currently in the atmosphere
Can global warming melt these methane ice deposits?
This would profoundly increase the greenhouse effect
La Brea Tar Pits
The Rancho La Brea Tar pits are a famous series of natural tar (asphalt) pits in Los Angeles
La Brea Tar PitsPools of water covers the sticky tar, and for thousands of years, animals who tried to drink the water became trapped in the tar, creating a treasure trove of fossils
The predators who fed on the trapped prey, also became trapped
La Brea Tar PitsSince 1901, over one million bones of Pleistocene animals have been removed by paleontologists, including saber-toothed cat and giant sloth
Oil Spills on land
In general, oil spills on land are small and confined
Pipe line ruptures, train wreaks, tanker truck accidents and illegal waste dumping are the most common sources of spill
This spill in Siberia was burned off, but that creates airborne oil-smoke pollution
Casualty of Warfare
In July 2006, Israel attacked the Hezbollah in Lebanon
In the first week of the conflict, Israeli fighter planes struck the Jiyyeh power plant just south of Beirut
The attack set ablaze five oil tanks and caused a 110,000 gallon fuel oil spill along the eastern Mediterranean coast
Casualty of Warfare
Because of the conflict, serious oil cleaning did not start until September, two months after the bombing
The biggest losers were the endangered green sea turtles that could not lay that year’s clutch of eggs along the Lebanon beaches
Casualty of Warfare
During the first Iraq war, Sadam had his retreating troops set over 800 oil wells in Kuwait on fire
Casualty of Warfare
The fires consumed an estimated six million barrels of oil daily
Their immediate consequence was a dramatic decrease in air quality, causing respiratory problems for many Kuwaitis
Casualty of WarfareThe sabotage of the oil wells also impacted the desert environment, which has a limited natural cleansing ability
Oil from the wells formed about 300 oil lakes that contaminated around 40 millions tons of sand and earth.
Oil and Water Don’t Mix
The news concentrates on major spills, but most oil spills are small, but in the course of a year, they can add up
The U.S. Coast Guard reports that there are about 10,000 oil spills in U.S. waters each year, totaling 15 to 25 million gallons
It is estimated that 600,000 tons of oil per year naturally escapes from permeable rocks into the oceans
Oil and Water Don’t Mix
When an oil spill occurs at sea, the oil, being less dense than water, floats
The lightest, most volatile hydrocarbons start to evaporate immediately, causing air pollution
Over several months, sunlight and bacteria action, can destroy up to 85% the oil, leaving thick asphalt lumps that can persist for many months
Oil and Water Don’t Mix
If a spill is small, it can be contained by floating barriers, and the oil skimmed off of the surface
Chalk, wood shavings and peat moss have been used to soak up oil
In big spills, detergent is added to the oil to speed up decomposition, but detergent is toxic to fish and birds
Oil and Animals Don’t Mix
Oil is toxic to marine life, causes water-birds to drown when their feathers become coated and decimates fish and shell fish populations
Oil and Animals Don’t Mix
Feathers can be cleaned of oil using soap and water, but it is very traumatic to the bird
The survival rate is low
IXTOC 1 Oil Well
Ixtoc I was an exploratory oil well platform in the Gulf of Mexico, about 600 miles south of Texas
On June 3, 1979, the well suffered a blowout and became the largest unintentional oil well spill in history