energyresources

2. (OIL & GAS)

3. Crude Oil Definition
 A mixture of hydrocarbons that exists in liquid phase
in natural underground reservoirs and remains liquid
at atmospheric pressure after passing through surface
separating facilities. Depending upon the
characteristics of the crude stream, it may also
include.
1. Small amounts of hydrocarbons that exist in gaseous
phase in natural underground reservoirs but are
liquid at atmospheric pressure after being recovered
from oil well (casing head) gas in lease separators.

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2. Small amounts of nonhydrocarbons produced with
the oil, such as sulfur and various metals.
3. Liquid hydrocarbons produced from tar sands, oil
sands and oil shale. Liquids produced at natural gas
processing plants are excluded. Crude oil is refined to
produce a wide array of petroleum products, including
heating oils; gasoline, diesel and jet fuels; lubricants;
asphalt; ethane, propane, and butane; and many other
products used for their energy or chemical content.

5. Formation of oil and gas
 The petroleum oil that becomes gasoline and many
other useful products wouldn’t exist without tiny
plants, algae and bacteria, which settled to the bottom
of the sea as they died millions of years ago.
 There’s no oxygen under the earth’s crust, so the
organic matter in the sediment changed into a
substance scientists call kerogen. And when the
temperatures rose to 110° Celsius or higher the kerogen
gradually changed into oil. Under hotter conditions it
changed into natural gas. The process takes at least a
million years.

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 Crude oil is a complex mixture of hydrocarbons. In
other words, it is made up of hydrogen, carbon and
traces of other substances. Its texture varies, but it is
generally liquid. Natural gas is mainly made up of the
chemical compound methane. It is gaseous, or lighter
than air

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 If the story ended there, oil and gas might never have
become the global energy sources they are today. The
deposits would be so scattered that we would have
almost no chance of extracting them in usable
amounts.
 Even after oil has formed in the rock, pressure
continues to rise, squeezing the oil out or upwards
through rocks that have more pores, or spaces, within
them.

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 All oil moves like this. Some of it eventually reaches
the surface and seeps out naturally into land or water,
but most of it eventually comes up against a layer of
rock that it can’t move through. This impermeable
rock forms a seal or trap, and slowly, very slowly, the oil
builds up. As it does, it forms a reservoir.
 Reservoirs are rock formations that hold oil, natural
gas or both within their pores, like a fossilized sponge.
Reservoirs can be massive. Some may be as large as
London, Hong Kong or New York

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 If only finding them was as easy as mapping a city.
Rocks also move over millions of years. Their
formations can be extremely complex. This makes oil
and gas reservoirs extremely difficult to find.

12. The science of searching
Forming an educated guess
 There may be no more unexplored frontiers on earth,
but deep inside the earth there is plenty that we don’t
yet know.
 Oil companies have a range of technologies to help
them locate oil and gas reservoirs deep beneath land
and sea. But the search remains a complex business.
Success is never certain.

13. Improving the odds
 In the early days of oil exploration, oil companies and
prospectors really had no idea what they were looking
for. They focused their search on areas near seepages,
where oil bubbled up naturally in pools. Then they
sunk a drill and hoped for the best.
 The rate of success has improved greatly since those
early discoveries, from 10% or less to more like 50%.
New technologies developed which may improve the
odds.

14. Drilling
 Drilling is still the only sure way to find out whether
there’s oil or gas down there. But drilling is expensive.
Each project can cost tens of millions of dollars or
more. So before we drill, we do as much planning as
possible. And that can take years.

15. The geologist’s eye
 We start with what we can see. Both geologists and
geophysicists provide crucial insights at this stage in
the exploration process. Geologists look at what rocks
are made of and the formations they make in the
earth. Geophysicists use physical characteristics, such
as magnetic and gravitational properties, to guess the
type and shape of subsurface rocks.

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 Aerial photography from aircraft and satellites can be
revealing. The same tectonic shifts that formed
mountains and other topographical features above the
earth’s surface also shaped the rock formations down
below. To the trained eye, these photographs can say a
lot about what lies beneath the soil.
 Aircraft can measure the gravitational pull over an
area. Even small gravitational differences can reveal
large clues about the density of underlying rocks.

17. Using sound waves to get the
picture
 But the most powerful tool available to us is the
acoustic survey. Geophysicists use air guns to fire
acoustic pulses down through the rock. The sound
waves bounce back like echoes, revealing different
layers and depths.
 This data gives our experts the information they need
to map reservoirs and identify whether they’re filled
with oil, gas or merely water.

18. Safety first
 Because crude oil and natural gas are hot and highly
pressurized, we have to take great care to control
pressure during the drilling process.
 Everyone involved in a drilling project undergoes
rigorous safety training. Risks are assessed at every
step. Increasingly we plan exploration projects
remotely, using data instead of site visits, which means
fewer employees and contractors are exposed to
potential dangers on the actual rig.

19. Extracting oil and gas
 After we’ve established that there are large quantities
of oil or gas (or both) at a drilling location, this site is
known as a field. The next step is to plan and build a
production facility, taking environmental, social and
logistical factors into account.

20. Working with local economies
Using new technology
 Over the decades-long lifespan of most production
facilities, chances are new technologies will help us
reach deeper and deeper into reservoirs, helping us to
extract more of the resources within it.
 Is the world running out of oil and gas? Not
immediately. By most estimates, today’s known
reserves would last for at least another 40 years at
current usage levels. In other words, these estimates
don’t take new discoveries into account. Meanwhile,
new technologies are helping us tap large amounts of
oil and gas that were once considered unreachable.

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 Not long ago drilling only went in one direction.
Down. Now we can drill at any angle, including
straight out horizontal. At Wamsutter gas field in
Wyoming, USA, horizontal drilling has helped us
reach large amounts of natural gas that were
previously trapped within rock formations too tight to
let the gas flow naturally.

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 Here are a few other recent and developing
innovations that may help us get more oil and gas from
known reservoirs:
Fracturing the rocks
 By exerting the right level and type of pressure into
rocks with tight pores, we can cause fine cracks that
stimulate a freer flow of natural gas deposits that
would previously have remained trapped there.

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Injecting water
 Injecting water into a reservoir to flush out some of the
remaining oil trapped in rock pores is a long-
established technique. Using water with a lower salt
content, a process BP developed and owns, appears to
boost oil recovery by as much as 40%.

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Injecting CO2 into wells
 Injecting natural gas is one way of flushing more oil
out of a well. Tests have shown that carbon dioxide,
which can be separated from oil and other
hydrocarbons during hydrogen power production, may
be an effective substitute. Putting this CO2 back into
the reservoir means it won’t be released into the
atmosphere, where it would add to the greenhouse
gases believed to cause global warming.

27. Moving oil and gas
 Most of the world’s known oil and natural gas supplies
are a long way away from the places where these
resources are the most in demand. Even land-based
production facilities may be many kilometers from the
closest refinery or distribution terminal.
 We transport crude oil in two main ways: pipelines and
shipping.

28. Oil transport

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 The choice depends on each project’s logistics,
economics and location, as well as environmental
considerations. Meanwhile, arranging to get large
amounts of oil, gas and energy products to all the
places where they are needed is a steady and
demanding job in itself.

30. Making fuels and products
 In its raw form, crude oil is practically useless. Before it
has any real value it must be processed into products
like gasoline, motor oils, bitumen and the chemicals
that make adhesives, cosmetics and other useful
products.
 We do this processing at our refineries.

31. How refining works
Transforming crude oil with
chemistry
 Refining is a chemical process. So to really understand how
it works we need to know a little basic chemistry.
 Crude oil is mainly made up of hydrocarbons – chains of
carbon atoms and hydrogen atoms. The chemical bonds
that link these chains together can be broken up and linked
in different ways. In fact, the hydrocarbon compound is the
most versatile on the chemical charts. It can make an
estimated 2.5 million possible combinations. Longer,
heavier molecules can be transformed into lighter ones and
vice versa.

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 But crude oil is far from pure. It can also contain
substances that need to be removed because they
would damage an engine or other machinery. In the
refinery, we remove sulphur, nitrogen, oxygen, water
and other trace substances and then dispose of them
safely.

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Vaporizing the crude oil
 The first step in separating oil into useful products involves
heating it to a about 350° Celsius. It is then pumped into a
fractioning tower.
 If you have ever seen an oil refinery from a distance, these
are the tall, slender towers that jut up above the horizon.
The vaporized oil rises up the tower through trays with
holes in them. As the gas cools, its components condense
back into several distinct liquids. Lighter liquids like
kerosene and naptha, a product used in chemicals
processing, collect near the top of the tower, while heavier
ones like lubricants and waxes fall through weirs to trays at
the bottom.

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 Demand for gasoline is high, so we use the flexibility
of the hydrocarbon compound to turn some of the
heavier components from the fractioning tower into
gasoline. Reforming and alkylation are two such
processes. Cracking is another. It breaks large
hydrocarbon molecules down into smaller ones,
making the end product runnier

35. Fractionating tower

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 After distillation, gasoline and other engine fuels go on
for further processing elsewhere in the refinery. They
will leave the refinery by pipeline or truck, having
been transformed from a raw material into fuels with
marketable octane ratings and specific engine
properties.

37. Refined products
One resource, thousands of uses
 The vast majority of the crude oil that goes through
one of our refineries leaves it as gasoline. But the range
of products we produce is much wider than
automotive fuels. In fact, these products touch almost
every aspect of modern life.

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 Here are a few of our refined products:
Liquefied petroleum gas
(LPG)
 Together propane and butane are known as LPG, which is stored
in metal containers under pressure as a liquid. It is used for
heating and cooking, especially when portability is needed – in
camping stoves, for example, or on boats.
Kerosene (paraffin)
 Kerosene was the first major product to be refined from crude oil
in the late 19th century. At that time it was mainly used for
lighting in oil lamps. Today its main use is as jet aircraft fuel.

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Lubricating oils
 Without lubricants, the world might not stop spinning
but everything on it would grind to a halt. Lubricants
have thousands of uses, from fixing squeaky doors to
oiling industrial machines and automotive engines.
Heavy fuel oils
 These are used in large industrial boilers, in power
stations for example, and to raise steam to drive
turbines on ships.

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Bitumen
 This is the heaviest product from the refinery.
Essentially it’s what is left after everything else has
been removed from the crude oil. When heated, it can
be used in road construction and as a waterproofing
material for roofs.
Waxes
 Wax is a by-product of the refining process. It is used
to make candles, electrical insulation and waterproof
coverings for food cartons.

41. Selling fuels and products
 At service stations, ports and airports around the
world, fuels and motor oils help keep the world in
motion.

47. References
 http://www.bp.com/en/global/corporate/about-
bp/what-we-do/finding-oil-and-gas/how-oil-and-gas-
form.html.
 http://www.indexmundi.com/energy.aspx?country=pk
 http://www.indexmundi.com/g/g.aspx?c=pk&v=136