Figure 1.5

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Environmental Physics

Chapter 7:

Fossil Fuels

Copyright © 2008 by DBS




Introduction


Nearly 90% of all energy is derived from fossil fuels


Nonrenewable energy source


Oil is in the shortest supply


Dependence on oil is a problem!

Figure 1.5:

Energy consumption by source for the world and for the United States: 2003.

Introduction


US domestic energy production is dominated by coal


Energy production is linked directly to economic growth


Resource Terminology


Amount of resource remaining (unused or undiscovered) is difficult to predict


Predictions are based on incomplete exploration


Economic and technical factors affect the ability to extract the resource


Resource Terminology


McKelvey diagram


Figure 7.1:

The McKelvey
diagram for categorizing
reserves and resources
relates the variables of
geological certainty and
economic feasibility.

Upper left =
least
expensive

Reserve


well known through
geologic exploration,
recoverable at current prices
with current technology

Undiscovered
resources

Known to exist but
expensive to extract

Resource Terminology


Economic /uneconomic and known/undiscovered dividing line changes with time


Reserves

Resource Terminology


Reserves


Proven reserves


reasonably certain of production using current technology


Indicated reserves
-

believed recoverable using improved technology


Inferred reserves


expected deposits not yet measured


Reserves

Inferred

indicated

Proven

Resource Terminology


Size of reserves is established by the energy industry


Old reserves exhausted


new reserves found


Except! Domestic oil…


Figure 7.2
:

U.S. crude oil reserves. Above the line are annual additions to reserves (the 1970
peak is Alaskan oil), and below the line is annual production. Note that the addition of reserves is
less than our production.

Resource Terminology

How do we estimate reserves?

1.) Quantitatively:


No. of barrels of oil contained in a unit volume of geological structure is a fixed amount


Total volume of geological structure x barrels per uni t volume = total reserve


2.) ‘Behavioristic approach’:


History of oil production is extrapolated

into the future to estimate the amount left


e.g. Hubbert forecast of 1969



Historical use begins with continuous

increase, reaching a maximum and

tailing off as easy deposits are

exhausted and prices rise



Figure 7.3:

Hubbert oil
-
depletion curve for world oil production. The
solid line shows actual production, using updated DOE data.

By 2050 oil production will
be at 10% of present level

Resource Terminology


Resource analysts do not like the behaviorist approach


Question should be answered with hard geological data


Does not take into account new technology available for extraction or discovery of new resources


Just estimates!

Resource Terminology

Map Description

This map identifies the ratio of domestic oil reserves to the domestic rate of production (R/P), in years,
for individual countries, as well as some regional totals. Note that nearly all countries (assuming no
importation of oil) are expected to deplete their usable supply or “run dry” of oil before 2100.

Oil


World appetite for oil continues to grow…

Figure 7.4:

World petroleum consumption, 1960

2003. The Organization for Economic
Cooperation and Development (OECD) countries include the United States, Japan, Western
Europe and Canada.

2003:

82 MBPD


Of which
USA used

19 MBPD

Hubbert’s Peak (1956)


BBLS = barrels


CUMULATIVE PRODUCTION = past production


ULTIMATE = cumulative production plus future production




Hubbert’s
ultimate

DeGolyer and
McNaughton’s
ultimate

1970

14

US Oil Production

15

Oil


US consumes more oil than any other country


Produces more oil than any other country except
Saudi Arabia and Russia)



US uses ¼ of the world's oil but has less than 2 % of
the world's known oil reserves, will last only a few
more years (depending on new discoveries)

Figure 7.5:

World oil reserves and oil use by country, 2003.

Table 7
-
2a, p. 212

Oil


Prior to 1989 and the collapse of communism, the former USSR had the 3
rd

largest oil reserves in
the world


New republics have a share in the oil resources


use them to develop economically


e.g. Kazakhstan, largest discovery of oil in last 25 yrs


Presents issue due to ethnic tensions, Russia’s claim to oil rights and existing pipelines for export

Route through
russia to Black Sea


Bottle neck at
Bosphorus

Route through Iran
to Persian Gulf


RISKY!

Route through
Azerbaijan to Turkey
moves 1 MBPD

Oil


First commercial oil well…1859

Figure 7.6:

The world’s first commercial oil well, Titusville, Pennsylvania, 1859. Colonel
Edwin Drake

(in top hat)
, conceived the idea of drilling for oil and used the primitive rig
pictured in the background.

69 feet,
40BOPD

Oil


Use of oil grew rapidly after 1859 because it could be used as a substitute for expensive whale oil


Oil is now crucial to the world’s economy


Substitution is difficult


transportation, agriculture, petrochemicals

Figure 7.7
:

U.S. oil consumption by end use, 2003.

Oil


Petroleum or crude oil is a mixture


oil, natural gas, asphaltic semi
-
solids


All petroleum deposits contain gas but not all gas deposits contain oil


Complex mixture of hydrocarbons of various molecular weights plus other organics


Composition varies widely

Oil


Refining


conversion of crude into useful products


Fractional distillation


separation according to btp.


Passed through fractionating tower (40 m high)


Products condense and are collected (heaviest at bottom, lightest at top)

Figure 7.8:

At the refinery, the petroleum fractions are separated thermally in the fractionating
tower, then individually treated to produce the products listed.

Oil


Originates from the decay of organic material buried over millions of years under high pressures
and temperatures


Oil and gas migrates through rocks and accumulates in deposits


Found in porous/permeable reservoir rocks (sandstone, limestone and shale) surrounded by
nonporous rock

Figure 7.9:

Typical petroleum trap. The upper boundary of the trap is an impermeable layer of
rock called a roof or caprock.

Oil


Well drilled into a reservoir will produce results by natural flow


To increase and sustain removal a pump may be used


Secondary recovery involves using water to provide increased pressure


Tertiary methods are needed to extract more than the initial 35 % (steam, N
2
, CO
2

injection),
anywhere between 10
-
30 %

Fig. 7
-
10b, p. 217

Figure 7.10:

Enhanced oil recovery
methods.


Oil


1968


largest oil field in US discovered on Alaska’s North slope (Prudhole Bay)


10
-
20 x10
9

barrels


Difficult to move oil tankers from Atlantic ocean through NW passage


1977
-

Trans
-
Alaska pipeline to nearest ice
-
free sea port


Production is decreasing


Look to Arctic National Wildlife Reserve’s 1002 area (ANWR)

Oil Spills


USA


Exxon Valdez largest spill in US


March 24 1989


S. coast Alaska, 11 million gallons of oil


Killed hundreds of thousands of birds/damaged local fishing industry


$45M spent on wildlife rescue and rehabilitation


Cleanup completed in 1992



World


Persian Gulf War


60
-
250 million gallons


Oil wells set deliberately ablaze


A pool of saffron
-
colored oil paints swirls along Alaska's shoreline following the Exxon Valdez oil spill in
1989. Although it was not large compared to other spills, the Valdez oil spill was one of the world's most
ecologically devastating disasters, spoiling more than 1,200 miles (1,931 kilometers) of shoreline,
including three national parks, three national wildlife refuges, and one national forest.

Oil


US has drilled more wells than any other country


Wells are deeper than ever before and only 30%

of drillings is successful



Most increases to US reserves expected to come

from offshore drilling



Offshore drilling x10 more expensive than onshore


Oil and gas brought to shore through pipelines


Figure 7.11:

Offshore drilling rig
operating in the Baltimore Canyon area.

End


Review


‘There must be energy down there’ cartoon

Natural Gas


Mixture of light hydrocarbons, primarily methane (CH
4
)

Natural Gas

Natural Gas

Nonassociated gas



natural gas found alone

Associated gas



found with crude oil

First US gas well was on the shore of Lake Freedonia, NY in 1821


Storage and transport


major difficulty may be liquified (LNG)


For the expansion of gas industry major pipelines were needed

>>> 1 million miles of pipe

Natural Gas


Growth of gas consumption:



1950
-
1970 x4



Slowed in 1970’s



Steady at 22 tcg (trillion cubic feet)

Natural Gas


Many uses…


Good substitute for oil (cleaner burning)


Helps to reduce dependence on foreign oil


Figure 7.12
:

U.S. natural gas consumption by end
-
use sector: 2003.

Chemical feedstock
= ammonia, fertilizers,
plastics, rubber, etc.

Natural Gas


World reserves ~ 5500 tcf, what is the estimated lifetime at consumption rate of 82 tcf per year?


US production peaked in 1973 at 24 tcf

Figure 7.13
:

U.S. natural gas consumption by year: 1950

2003.

5500 tcf / 82 tcf/yr = 67 years

Natural Gas


Additional unexploited resources:


(1) gases trapped within coal beds


(2) Devonian shale under most of eastern USA


(3) gas in so

called ‘tight
-
sands) in the Rocky Mountains



All these sources are difficult to drill, require explosives or high water pressures

Natural Gas


Producing electricity from gas is preferable over coal and oil (whose primarily use is transport)


Produces almost no SO
2

or mercury and 1/3 of the CO
2

of a coal plant (dirty coal!)


Incomplete combustion yields methane (powerful GH gas)


Short construction time

Air pollution worries of
1970’s
-
1980’s made gas
more popular than ever

Electricity Generation by Fuel 1980
-
2030

(billion kilowatt hours)


Source: EIA Annual Energy Outlook 2008 With Projections to 2030

Coal


World’s most abundant fuel


US has ¼ of total reserves


Estimated it will last 210 years at

current rates

Figure 7.14:

World recoverable
reserves of coal, 2003.

Coal


Consume

~20 x 10
15

Btu coal vs.40 x 10
15

Btu oil



Can’t substitute coal for oil



Turn coal into liquid?



Increased use is constrained by

demand, not supply

Coal

Over thousands of years peat
(decomposed plant matter) is
transformed into coal

Development of coal

Lower S

Coal


Consumption of coal in the US increasing


Percentage contribution to total energy is decreasing


Due to change to cleaner burning oil and natural gas,

railroads changing from coal to diesel and electric


Use in electric utilities increased (consume 90% of all coal produced)



Figure 7.15
:

U.S. coal consumption by sector: 1950

2003.

The Washington Post 03/20/08

Coal

Figure 7.16
:

U.S. coal deposits.

Since 1940’s production shifted
west, from underground to
surface mines

Due to air pollution laws,
search for cleaner coal,
thicker seams

Coal


Coal seams vary in thickness from a few inches to hundreds of feet


60% coal produced by strip mining


ripping tops off mountains

Aerial view of a Montana strip mine.

Dragline used in strip mine to remove coal.

Coal

Synthetic oil from gas and coal


‘gasification’ and ‘liquefraction’ of coal


Produces synfuels


Technology is 200 years old, but currently not economically attractive


Oil Shale and Tar Sands


Oil shale


oil trapped in rocks


Large deposits in US > oil reserves


Requires energy input to process the shale



Summary


Fossil fuels are projected to constitute the majority of our energy supplies


Petroleum supplies 40 % of the world’s energy


Estimates of the lifetime of resources < 100 years for oil and gas


Petroleum supplies 40 % of the world’s energy


Oil and gas accumulate in reservoir rocks capped with impermeable rocks


Oil may be extracted using primary, secondary and tertiary techniques


Coal is classified according to how much carbon it contains


Coal may be mined above ground or below the surface


Oil and gas produce less pollution than coal


Coal can be converted into oil and gas by liquefraction and gasification

End


Review

Fig. 7
-
19, p. 235

p. 235

Fig. 7
-
20a, p. 236

Fig. 7
-
20b, p. 236

Table 7
-
4, p. 237

Fig. 7
-
21, p. 238

Fig. 7
-
22, p. 238

Fig. 7
-
23, p. 239

Fig. 7
-
24, p. 239

Figure 7.24:

Seismic operations print
-
out map for oil location. Each horizontal
line represents a detector at a different distance which records pulse strength (
y
axis) vs. time of travel of the shock wave (
x
axis).

History of Solar Heating

F

F


Summary


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