Collection of some useful information from different websites about petroleum

1. An introduction to Petroleum
Petroleum, along with oil and coal, is classified as a fossil fuel. Fossil fuels are formed
when sea plants and animals die, and the remains become buried under several
thousand feet of silt, sand or mud. Fossil fuels take millions of years to form and
therefore petroleum is also considered to be a non-renewable energy source.
Petroleum is formed by hydrocarbons (a hydrocarbon is a compound made up of
carbon and hydrogen) with the addition of certain other substances, primarily sulphur.
Petroleum in its natural form when first collected is usually named crude oil, and can be
clear, green or black and may be either thin like gasoline or thick like tar.
There are several major oil producing regions around the globe. The Kuwait and Saudi
Arabia's crude oil fields are the largest, although Middle East oil from other countries in
the region such as Iran and Iraq also make up a significant part of world production
figures.
The North Sea crude oil fields are still fairly full, and are arguably the second most
influential oil field in economic terms. Texas, once the world's major oil region, is now
almost completely dry.
In 1859 Edwin Drake sank the first known oil well, this was in Pennsylvania. Since this
time oil and petroleum production figure grew exponentially.
Originally the primary use of petroleum was as a lighting fuel, once it had been distilled
and turned into kerosene. When Edison opened the world's first electricity generating
plant in 1882 the demand for kerosene began to drop.

2. However, by this time Henry Ford had shown the world that the automobile would be
the best form of transport for decades to come, and gasoline began to be a product in
high demand.
World War I was the real catalyst for petroleum production, with more petroleum being
produced throughout the war than had ever been produced previously. In modern times
petroleum is viewed as a valuable commodity, traded around the world in the same way
as gold and diamonds.
Most people tend to believe that petroleum is mostly used to power internal combustion
engines in the form of gasoline or petrol. Although our autombiles and other forms of
transport do consume the highest quantity of petroleum it is used for a vast array of
applications.
In its thickest form, the almost black petroleum is named bitumen, this is used for paving
road, forming the blacktop, it is also an excellent water repellent and is used in roofing.
Petroleum is also a major part of the chemical makeup of many plastics and synthetics.
Possibly the most startling usage of petroleum for many people is its appearance in
foodstuffs such as beer and in medications such as aspirin.
The world has a limited supply of petroleum, and current estimations tell us that within
the next few decades mankind will have completely depleted this valuable natural
resource. Although measures have been taken to ensure that there are cheap,
renewable fuel options in place for the eventuality it is still obvious that mankind faces a
serious problem when petroleum supplies finally run out.

3. Petroleum Chemistry
Petroleum Chemistry is made of a mixture of different hydrocarbons. The most prolific
hydrocarbons found in the chemistry of petroleum are alkanes, these are also
sometimes knows as branched or linear hydrocarbons.
A significant percentage of the remaining chemical compound is the made up of
aromatic hydrocarbons and cycloalkanes. Additionally petroleum chemistry contains
several more complex hydrocarbons such as asphaltenes.
Each geographical location and hence oil field will produce a raw petroleum with a
different combination of molecules depending upon the overall percentage of each
hydrocarbon it contains, this directly affects the colouration and viscosity of the
petroleum chemistry.
The primary form of hydrocarbons in the chemistry of petroleum are the alkanes,
which are also often named paraffins. These are termed saturated hydrocarbons and
the exhibit either branched or straight molecule chains.
The paraffins are very pure hydrocarbons and contain only hydrogen and carbon; it is
the alkanes which give petroleum chemistry its combustible nature. Depending upon the
type of alkanes present in the raw petroleum chemistry it will be suitable for different
applications.
For fuel purposes only the alkanes from the following groups will be used: Pentane and
Octane will be refined into gasoline, hexadecane and nonane will be refined into

4. kerosene or diesel or used as a component in the production of jet fuel, hexadecane will
be refined into fuel oil or heating oil.
When it comes to the chemistry of petroleum which does not contain a significant
quantity of the kinds of paraffins required to produce a combustible fuel then things
become simpler, as many non-fuel applications of petroleum are far more lenient in the
chemical compound of the raw petroleum.
The exception to this are the petroleum molecules which have less than five carbon
atoms, these are a form of natural petroleum gas and will either be burned away or
harvested and sold under pressure as LPG (Liquid Petroleum Gas).
The cycloalkanes, which are also often referred too as the napthenes are classed as a
saturated form of hydrocarbon. By saturated we mean the molecule contains either one
or several carbon rings with atoms of hydrogen attached to them. These hydrocarbons
display almost identical properties to paraffins but have a much higher point of
combustion.
Lastly, the aromatic hydrocarbons are another form of unsaturated hydrocarbon. The
specific difference between the other hydrocarbons in the petroleum molecule is that the
aromatic hydrocarbons will contain benzene rings, with atoms of hydrogen attached to
them. Aromatic hydrocarbons tend to produce far more emissions when combusted,
many will have a sweet, sickly smell to them, hence the name aromatic hydrocarbons.
The quantity and percentages of the specific types of hydrocarbons in raw petroleum
chemistry can be determined by testing in a laboratory. The process involves
extracting the, molecules using some form of solvent and then separating them using a
gas chromatograph. Finally an instrument such as a mass spectrometer will be used to
examine the separate molecules in the chemical compound of the sample.
Petroleum Composition
Most people presume petroleum to be similar to gasoline or petrol, simply a less pure
form, which needs to be refined. In actuality the chemical composition of petroleum in
its raw state can vary extremely.
This variation is the reason why petroleum composition differs so much in colour and
viscosity between crude oil fields and geographical areas.
Petroleum, or crude oil as it is now usually referred too when raw, contains several
chemical compounds, the most prolific being the hydrocarbons themselves which give
thepetroleum composition its combustible nature.

5. Although the composition of petroleum will contain many trace elements the key
compounds are carbon (93% – 97%), hydrogen (10% - 14%), nitrogen (0.1% - 2%),
oxygen (01.% - 1.5%) and sulphur (0.5% - 6%) with a few trace metals making up a
very small percentage of the petroleum composition.
The actual overall properties of each different petroleum source are defined by the
percentage of the four main hydrocarbons found within petroleum as part of the
petroleum composition.
The percentages for these hydrocarbons can vary greatly, giving the crude oil a quite
distinct compound personality depending upon geographic region. These hydrocarbons
are typically present in petroleum at the following percentages: paraffins (15% - 60%),
napthenes (30% - 60%), aromatics (3% to 30%), with asphaltics making up the
remainder.
The composition of petroleum is defined as laid out above, and it is this composition
which gives the crude oil its properties.
Raw petroleum is usually dark brown or almost black although some fields deliver a
greenish or sometimes yellow petroleum. Depending upon the field and the way the
petroleum composition was formed the crude oil will also differ in viscosity.
At the extreme ranges petroleum can be almost solid, and required a significant
investment of resources to refine into a useable state as anything other than bitumen. At
the other end of the scale the petroleum composition can be a clear fluid resembling
kerosene or gasoline, needing very little refining to be useable as a fuel.

6. When discussing the composition of petroleum it is important to note that the compound
of the raw petroleum tends to dictate the usage of the refined product. Petroleum is
generally measured in volume, and for some composition of petroleum it is not cost
effective to refine these into fuel.
A lighter, less dense raw petroleum composition with a compound that contains higher
percentages of hydrocarbons is much more profitable as a fuel source. Whereas other,
denser petroleum composition with a less flammable level of hydrocarbons and sulphur
are expensive to refine into a fuel and are therefore more suitable for plastics
manufacturing and other uses.
Unfortunately the worlds reserves of light petroleum (light crude oil) are severely
depleted and refineries are forced to refine and process more and more heavy crude oil
and bitumen.
In some cases the refining process will need to remove carbon and add hydrogen,
adding an extra, costly step to the refining process. This change in compound of the
world's energy producing petroleum and the associated rise in refining costs has directly
affected the price of gasoline across the world.
Petroleum Formation
Petroleum formation occurs by various hydrocarbons combining with certain minerals
such as sulphur under extreme pressure. Modern day scientists have proven that most
if not all petroleum fields were created by the remains of small animal and plant life
being compressed on the sea bed by billions of tons of silt and sand several million
years ago.
When small sea plants and animals die they will sink, they will then lie on the sea bed
where they will decompose and mix with sand and silt. During the decomposition
process tiny bacteria will clean the remains of certain chemicals such as phosphorus,
nitrogen and oxygen.

7. This leaves the remains consisting of mainly carbon and hydrogen. At the bottom of the
ocean there is insufficient oxygen for the corpse to decompose entirely. What we are
left with is the raw materials for the formation of petroleum.
The partially decomposed remains will form a large, gelatinous mass, which will then
slowly become covered by multiple layers of sand, silt and mud. This burying process
takes millions of years, with layers piling up one atop another.
As the depth of the sediment build up increases the weight of the sand and silt pressing
down on the mass will compress it into a layer which is much thinner than the original.
Finally, when the depth of the buried decomposing layer reaches somewhere around
10,000 feet the natural heat of the earth and the intense pressure will combine to act
upon the mass. The end result, over time, is the formation of petroleum.
With petroleum formation the actual temperature applied to the original organic mass is
critical in determining the overall properties of the resulting petroleum. Typically lower
temperatures during petroleum formation will result in thicker, darker raw petroleum
deposits, the most solid of which being a bitumen substance.
If the heat applied during the formation of petroleum process fluctuates too much then
gas will be produced, often separating from the petroleum, sometimes remaining mixed
with the raw oil. If temperatures are too high, in the somewhere over 450 degrees
Fahrenheit then the original biomass will be destroyed and no gas or petroleum is
formed.
As the mud and silt above the deposit become heavier and the forces placed upon the
silt and mud begin to change the bottom layers of the compressing layer above the
petroleum then it will turn into shale.

8. As the shale forms the oil will be forced out of its original area of formation. The raw
petroleum then moves to a new rock formation, usually termed a reservoir rock, and
lays trapped until it is accessed in some way.
As we can see, the formation of naturally occurring raw petroleum takes millions of
years, certainly far longer than can be deemed renewable, yet mankind has managed to
almost complete deplete the world supply in little more than a century.
It is important that people are educated and come to realise that burning such a
precious fuel, which takes so long to form, at such a rate as we do now is nothing short
of disastrous for the environment.
The Classification of Petroleum
For several decades now the crude oil or petroleum industry has classified the raw
crude by the location from which it was extracted. In other words, oil is classified by
geographic region. However, all oils from a particular region are not created equal.
Further classification of petroleum, derived from the density of the raw petroleum (API
gravity) and its various non-hydrocarbon components (especially sulfur), is then added
to the geographic designation. The end result of all this classification helps determine
the price of a specific barrel of crude as well as how much demand there is for that
particular oil.
In general, if the crude oil contains high levels of sulphur the petroleum classification is
termed ‘sour, if it has relatively low levels of sulphur the petroleum classification is
termed ‘sweet'. If the raw petroleum is of a high density then the petroleum classification
is termed ‘heavy' and if it is of a low density the petroleum classification is termed 'light'.
Density of oil is determined by the length of the hydrocarbons it contains. If it contains a
great deal of long-chain hydrocarbons, the petroleum will be denser. If it contains a
greater proportion of short-chain hydrocarbons it will be less dense. Besides chain
length, the ratio of carbon to hydrogen also helps to determine the density of a particular
hydrocarbon. The greater the amount of hydrogen in relation to carbon, the lighter the
hydrocarbon will be.Less dense oil will float on top of denser oil and is generally easier
to pump.
The hydrocarbons in crude oil can generally be divided into four categories:
• Paraffins: These can make up 15 to 60% of crude and have a carbon to
hydrogen ratio of 1:2, which means they contain twice the amount of hydrogen as
they do carbon. These are generally straight or branched chains, but never cyclic
(circular) compounds. Paraffins are the desired content in crude and what are
used to make fuels. The shorter the paraffins are, the lighter the crude is.
• Napthenes: These can make up 30 to 60% of crude and have a carbon to
hydrogen ratio of 1:2. These are cyclic compounds and can be thought of as

9. cycloparaffins. They are higher in density than equivalent paraffins and are more
viscous.
• Aromatics: These can constitute anywhere from 3 to 30% of crude. They are
undesirable because burning them results in soot. They have a much less
hydrogen in comparison to carbon than is found in paraffins. They are also more
viscous. They are often solid or semi-solid when an equivalent paraffin would be
a viscous liquid under the same conditions.
• Asphaltics: These average about 6% in most crude. They have a carbon to
hydrogen ratio of approximately 1:1, making them very dense. They are generally
undesirable in crude, but their 'stickiness' makes them excellent for use in road
construction.
When considering the petroleum classification it is important to consider the fact that
the overall classification will have an effect on the value, not just the physical properties.
For example, petroleum with a geographical classification from one region of the world
may be expensive to transport to another region of the world regardless of the suitability
of the raw petroleum as an overall substance. In general, lighter crude commands a
higher price because it contains more hydrocarbon chains that can be easily refined to
make gasoline and diesel, which are in high demand. The lower the sulphur content, the
higher the price as well because low-sufur, sweet crude requires less refining.
Classification of petroleum also indicates the best use for a particular field of
petroleum. One oil type is not necessarily “better” than another, but rather the different
types are useful in different applications. Light crude oil is preferable for refining into
gasoline as it produces a far higher yield than heavy. In a similar fashion,
sweet petroleum is often more desirable than sour petroleum as its use will cause far
less impact on the environment in the form of harmful emissions as it is burned. These
basic classifications of petroleum are further enhanced by a full molecular description
gained through a crude oil assay analysis.
Fuel from Crude
The primary uses of crude oil to this point have been in the production of fuel. A single
barrel of crude oil can produces the following components, which are listed by percent
of the barrel they constitute.
• 42% Gasoline
• 22% Diesel
• 9% Jet Fuel
• 5% Fuel Oil
• 4% Liquefied Petroleum Gases
• 18% Other products

10. Refining
Petroleum refining refers to the process of converting crude oil into useful products.
Crude oil is composed of hundreds of different hydrocarbon molecules, which are
separated through the process of refining. The process is divided into three basic
steps: separation, conversion, and treatment.
Separation
Separation refers to the process of distillation. Crude oil is heated in a furnace so that
hydrocarbons can be separated via their boiling point. Inside large towers, heated
petroleum vapors are separated into fractions according to weight and boiling
point. The lightest fractions, which include gasoline, rise to the top of the tower before
they condense back to liquids. The heaviest fractions will settle at the bottom because
they condense early.
Conversion
Conversion is simply the process of changing on kind of hydrocarbon into another. Of
the, the desired product is gasoline. Cracking is the process of taking heavier, less
valuable fractions of crude and converting them into lighter products. Cracking uses
heat and pressure to break heavier elements into lighter ones. Alkylation is another
common process, which is basically the opposite of cracking. In alkylation, small
gaseous byproducts are combined to form larger hydrocarbons.
>Treatment
Treatment is the final process of refining, and includes combining processed products to
create various octane levels, vapor pressure properties, and special properties for
products used in extreme environments. One common example of treatment is the
removal of sulfur from diesel fuel, which is necessary for it to meet clean air guidelines.
Treatment is highly technical and is the most time consuming step of refining.
Gasoline
Gasoline is the most popular product derived from petroleum and constitutes the largest
fraction of product obtained per barrel of crude oil. The hydrocarbons in gasoline have a
chain length of between 4 and 12 carbons. Internal combustion engines burn gasoline in
a controlled process called deflagration. Of importance in this process is the timing of
combustion, which can be adversely impacted by autoignition of gasoline. This leads to
the phenomenon commonly referred to as “engine knock.” In fact, the resistance to
autoignition is the largest difference between gasoline and jet fuel, jet fuel being highly
resistant to autoignition. A gasoline’s resistance to autoignition is expressed in its
octane rating. Octane levels are manipulated by the addition of a particular
hydrocarbon called octane. The higher the octane rating of the gasoline, the more the

11. fuel can be compressed. Higher compression means higher temperature and pressure
can be achieved inside the engine, which translates to higher power output.
Diesel
Diesel fuel consists of hydrocarbons of a chain length between eight and 21 carbon
atoms. Diesel has higher energy content per volume than gasoline. Because they
hydrocarbons in diesel are larger, it is less volatile and therefore less prone to
explosion, which is one reason it is preferred in military vehicles.
Unlike gasoline engines, diesel engines do not rely upon electrically generated sparks
to ignite the fuel. Diesel is compressed to high degree along with air, creating high
temperatures within the cylinder that lead to combustion. This process makes diesel
engines highly efficient, achieving up to 40% better fuel economy than gasoline
powered vehicles.
Until recently, diesel fuel contained a high degree of sulfur, which contributes to acid
rain. Because of their similar distillation points, diesel and sulfur contaminants are
removed from crude at the same time during refining. Government regulation now
requires that additional steps be taken to remove the sulfur so that diesel fuel is more
environmentally friendly. This is part of reason that diesel fuel costs more than gasoline
Heating Oil and Fuel Oil
Fuel oil is one of the “left-over” products of crude refining. It is often less pure than other
refined products, containing a broader range of hydrocarbons. Because of its
contaminants, fuel oil has a high flash point and is more prone to autoignition. It also
produces more pollutants when burned.
Jet Fuel
Jet fuel requires specific characteristics. Namely, it must have a low flammability and it
must be able to experience the cold temperatures associated with high altitude without
freezing. Jet fuel is based on kerosene, which is slightly heavier than gasoline.
Petroleum Industry
The petroleum industry is quite complicated. Part of what makes it so complicated is the
fact that most of the world’s oil supplies are control by state agencies and not by private
corporations. In fact, well over half of total world oil reserves are controlled by state
agencies in the Middle East. The somewhat complicated and intertwined operations of
these major industry players can make it difficult to understand why the industry works

12. as it does. To make it easier, the oil industry can be subdivided into two major
categories: National Oil Companies (NOCs) and International Oil Companies (IOCs).
International Oil Companies
International Oil Companies include familiar names like ExxonMobil and Royal Dutch
Shell. These are publicly traded corporations that function like any other corporation
except that the product the deal in is petroleum. IOCs all have long histories that
generally date back to the late 19th
century when they were formed. Most IOCs in the
United States arose from the break-up of Standard Oil, which was the dominant oil
corporation until 1911.
Several terms are often associated with IOCs. “Supermajor” is the most often used and
it refers to the 6 largest publicly traded oil companies in the world. Supermajors have
gone through many changes since the 1990s as a result of mergers and acquisitions
secondary to market forces, the introduction of NOCs (see next), and depression in oil
prices in the early 1990s. As a group, supermajors control 6% of the world’s oil.
Comparatively NOCs control 88% of the world’s oil. The six supermajors are as follows.
Name Location Revenue (Billions
of Dollars)
Reserve Size in
Billions of
Barrels
ExxonMobil Texas – United States 383 72
Royal Dutch Shell The Hague –
Netherlands
368 20
BP/Amoco London – United
Kingdom
308 18
Total SA Paris – France 229 10.5
Chevron California – United
States
204 10.5
ConocoPhillips Texas – United States 198 8.3
Reserve size is not the only way to divide the industry. It seems that reserve size is
most often used in reference to NOCs while reserve size and industry segment are both
used to describe IOCs. The American Petroleum Institute divides the industry into five
categories based on function. These divisions help to explain why having large
petroleum reserves does not automatically translate into large revenues and why the
supermajors, despite their relatively small reserve sizes in comparison to NOCs,
dominate the market. The industry segments are:
Category Function
Upstream Exploration and development of crude
Downstream Tankers, refineries, and consumers
Pipeline Any hazardous pipeline, including petroleum, liquid CO2,
etc.

13. Marine For transport by water of petroleum
Service and Supply
(General)
Equipment manufacturers, consulting firms, etc.
Most supermajors are referred to as “vertically integrated.” This means that divisions of
the company specialize in various segments of the industry like upstream, downstream,
and marine. While all supermajors participate in upstream and downstream operations,
some do not get involved in pipeline or marine segments. Most have some involvement
in service and supply.
The upstream segments of most supermajors are their primary income divisions. For
instance, Royal Dutch Shell make 2/3 of its profits from exploration and development of
crude. Because supermajors have been in the petroleum business the longest, they
have developed the necessary expertise to find and develop crude. This makes them
indispensible to the industry, even to NOCs. As a result of market dominance in this
segment, the supermajors do the majority of the upstream work in the industry and thus
derive most of their income from providing these services both for their own oil reserves
and to others.
Alternatives to Petroleum
In 2008, the top 15 oil consuming nations used nearly 60 million barrels of oil per day.
The United States accounted for roughly 19,500,000 of that, followed by China at
7,831,000. The world’s top oil producers in 2006, measured by barrels produced per
day, were Saudi Arabia, Russia, and the United States.
It is estimated that peak oil either has been reached, in 2006, or will be reached by
2020. Peak oil is the point when extraction of crude becomes increasingly more difficult
and costly. The result is high energy costs for everything from home heating to
transportation.
Roughly 90% of all vehicles in the world run on oil-derived products. This accounts for
roughly 70% of all petroleum used. In the United States, petroleum constitutes 40% of
the nation’s total energy use, most of which goes to the transportation industry. As fuel
costs continue to rise, the infrastructure of modern society is being threatened
Alternatives to the use of fossil fuels in general, and petroleum in particular, have been
sought for many reasons including the limited supply of readily accessible reserves,
national security, environmental impact, and profit.
As the primary use of petroleum is for transportation, replacing its use in that setting has
been the target of most investigations. The transportation industry accounts for 14% of
greenhouse gas emissions and is exceeded only by industrial processes and electrical
generation that rely upon coal. The retrieval, processing, and distribution of fossil fuels
accounts for another 11.3% of greenhouse gas emissions. Alternatives to petroleum
have included alcohol, solar, wind, hydrogen, and biofuels.

14. The following table illustrates the energy densities of common fuels. When energy is
standardized by energy density, the amount of energy in a given volume, it is easier to
compare.
Item Energy per Kilogram Energy Per Liter
Gasoline 47.2 megajoules 34 megajoules
Diesel 45.4 megajoules 38.6 megajoules
Hydrogen 143 megajoules 5.6 megajoules
Uranium 20 terajoules N/A
Coal 24 megajoules 20 megajoules
Lithium-ion battery 720 kilojoules N/A
Gasohol (E10) 43 megajoules 33.18 megajoules
Gasohol (E85) 33.1 megajoules 25.6 megajoules
Biodiesel 42 megajoules 33 megajoules
Ethanol 30 megajoules 24 megajoules
Joule = The amount of energy expended in applying a force of one newton over a
distance of one meter. By example, one joule is the approximate amount of energy
required to lift a small apple one meter off of the ground. For a 1000 kg car to
acceleration from 0 to 100 km/hr requires approximately 365 kilojoules. That would
require 10 mL of gasoline or 67 mL of hydrogen from the above table.
Kilojoule = 1,000 joules
Megajoule = 1 million joules
Terajoule = 1 trillion joules