1. Hydrocarbons, Nuclear, Gas Hydrate
9th July, 2014
H. SAIBI

2. Hydrocarbons
Oil and gas

3. Talk outline Part 1: Origin – How do oil and gas form?
Presenter notes: In this talk we will examine oil and gas from three angles.
In the first part we will think about the biological and geological processes responsible for the formation of oil and gas. In Practical Exercise 1 we investigate the rate at which oil and gas deposits form and consider the meaning of non-renewable versus renewable energy.
In the second part, we will look at the way geologists explore for new oil and gas deposits and consider the how oil and gas get from the well to the marketplace. In Practical Exercise 2, we will have a chance to explore for oil and gas fields ourselves in the ‘Prospector Game’.
In the third part, we will examine the political importance of oil and gas. Specifically we will look at which countries control production, consider global supply and demand, and think about the likely future of oil and gas in our society.
Part 2: Exploration and Production –
How do we find oil and gas and how is it produced?

4. Origin (1): The Nature of Oil and Gas
Petroleum: Greeks origin (Petro=Rock; oleum=Oil)
Called Hydrocarbons because 2 most important element in both crude oil and natural gas (Carbon + Hydrogen).
Difference between crude oil and gas: size of hydrocarbon molecules:
1-4 carbon atoms: gas (methane: CH4; ethane C2H6; propane C3H8; butane C4H10)
5 or more carbon atoms: Liquid
Crude oil: mixture of more than 100 hydrocarbon molecules (5-60 carbons in length).

5. Origin (2): Chemical composition of typical crude oil and natural gas
Carbon
84-87%
65-80%
Hydrogen
11-14%
1-25%
Sulfur
0.06-2%
0-0.2%
Nitrogen
0.1-2%
1-15%
Oxygen 0%

6. Origin (3): Chemistry Hydrocarbon Oil and gas are made of a mixture of
en.wikipedia.org/wiki/Image:Petroleum.JPG
en.wikipedia.org/wiki/Image:Octane_molecule_3D_model.png
Hydrocarbon
Questions for discussion: What is oil and gas? Where does it come from?
Presenter notes: As we begin to think about the origin of oil and gas, a basic question we need to answer is what exactly are oil and gas? Oil and gas are complicated mixtures of different hydrocarbons. A hydrocarbon is a large organic molecule. As the name suggests it is composed of hydrogen atoms attached to a backbone, or chain, of carbon atoms. Short chain hydrocarbons like methane are gases. Medium chain hydrocarbons like paraffin are liquids. Long chain hydrocarbons like bitumen are solids. When crude oil is extracted from the earth it may be a mixture of hydrocarbons in solid, liquid and gas states.
Oil and gas are made of a mixture of
different hydrocarbons.
As the name suggests these are large
molecules made up of hydrogen atoms
attached to a backbone of carbon.
Crude Oil

7. Origin (4): Plankton 10,000 of these bugs would fit on a pinhead!
cache.eb.com/eb/image?id=93510
10,000 of these bugs
would fit on a pinhead!
Plant plankton
Animal plankton
Presenter notes: It may come as a surprise but most of the world’s oil and gas is made up of the fossil remains of microscopic marine plants and animals. That’s why oil and gas are often referred to as a fossil fuel. One of the most important group of plankton involved in the formation of oil and gas are single-celled marine ‘plants’ called dinoflagellates, though many types of animal plankton are also important. Some oil and gas may have also originated from the remains of land plants, but we will not discuss these types of deposits in this talk.
en.wikipedia.org/wiki/Image:Ceratium_hirundinella.jpg
en.wikipedia.org/wiki/Image:Copepod.
Most oil and gas starts life as microscopic plants and animals
that live in the ocean.

8. Origin (5): Blooms Today, most plankton can be found where deep ocean
serc.carleton.edu/images/microbelife/topics/red_tide_genera.v3.jpg
Today, most plankton can be
found where deep ocean
currents rise to the surface
This upwelling water is rich in
nutrients and causes the
plankton to bloom
Blooms of certain plankton
called dinoflagellates may
give the water a red tinge
Presenter notes: In certain parts of the world’s oceans, plankton occurs in enormous quantities, or blooms. Exactly where those plankton blooms occur is controlled by ocean currents. The richest sites are where cold, nutrient rich waters rise to the surface from the deepest parts of the ocean. The nutrients found in these ‘upwelling zones’ feed plankton and allow them to reproduce quickly. A single litre of seawater may contain several million dinoflagellates. Where these plankton occurs in high numbers they may turn the water red. This phenomenon is known as red tide.
© Miriam Godfrey
Dinoflagellate bloom

9. Origin (6): On the sea bed
upload.wikimedia.org/wikipedia/en/0/04/Plankton.jpg
When the plankton dies it rains
down on sea bed to form an
organic mush
en.wikipedia.org/wiki/Image:Nerr0328.jpg
If there are any animals on the
sea bed these will feed on the
organic particles
Presenter notes: When plankton dies it slowly settles to the sea bed where it forms an organic mush. Usually there are lots of animals living on the sea floor that feed on this material. One important group is the polychaete worms. These are detritivores, which means they eat the dead and decay remains of other organisms
Sea bed

10. Origin (7): Black Shale However, if there is little or no
upload.wikimedia.org/wikipedia/en/0/04/Plankton.jpg
However, if there is little or no
oxygen in the water then animals
can’t survive and the organic
mush accumulates
Where sediment contains
more than 5% organic matter,
it eventually forms a rock
known as a Black Shale
Presenter notes: However, under certain conditions there may be very little oxygen on the sea floor. This may be because the ocean is deep and stagnant and oxygen has not been mixed down from the surface waters. No animal life can survive where the sea bed is completely lacking oxygen. Without animals to eat the dead plankton, the organic mush builds up on the sea bed. Where ocean sediment contains more than 5% organic mush it eventually forms a rock known as a Black Shale. The black colour comes from the dark organic matter that it contains. As we will see, Black Shale is what makes oil and gas.
© Earth Science World Image Bank

11. Origin (8): Cooking As Black Shale is buried, it is heated.
Organic matter is first changed by the
increase in temperature into kerogen,
which is a solid form of hydrocarbon
Kerogen
Around 90°C, it is changed into a liquid
state, which we call oil
Presenter notes: As more sediment accumulates on top, layers of Black Shale become buried more and more deeply in the Earth’s crust. As they do so, they slowly heat up because of the geothermal gradient. With progressive heating the organic material in the plankton undergoes chemical and physical changes. It gradually breaks down into smaller and smaller hydrocarbons. At temperatures of around 30°C, a solid, sticky bitumen is produced. Around 90°C liquid oil is formed. As temperatures reach 150°C, natural gases like methane are given off. A Black Shale that is heated and gives off oil and gas is known in the oil industry as a Source Rock.
Background notes: This is natural chemical ‘cracking’ of the hydrocarbons – where the initially large molecules are broken into progressively smaller molecules by the increase in temperature – much the same as long chain hydrocarbons can be ‘cracked’ commercially.
Oil
Around 150°C, it is changed into a gas
Gas
A rock that has produced oil and gas in
this way is known as a Source Rock

12. Origin (9): Migration
Source Rock in subsurface + Reservoir to hold gas/oil + Trap on the reservoir rock to concentrate gas/oil into commercial quantities
Hot oil and gas is less dense than the source rock in which it occurs
Oil and gas migrate upwards up through the rock in much the same way that the air bubbles of an underwater diver rise to the surface
Presenter notes: The hot oil and gas does not stay in the Source Rock for long. As the hydrocarbons are less dense than the water in the source rocks that surround them, they gradually migrate upwards through the rock in much the same way that the less dense air bubbles of an underwater diver will rise through water. The migrating oil and gas may travel up through the spaces between the sand grains that make up the rock (called pores) or they may find their way up through cracks, fissures, and faults in the overlying rocks. As we will see when we look at oil exploration, eventually oil and gas get trapped in pockets of rock known as reservoirs.
Rising oil
The rising oil and gas eventually gets trapped in pockets in the rock called reservoirs

13. Origin (10): Ancient Earth
© Ron Blakey, Arizona Flagstaff
During mid-Mesozoic times
around 150 million years ago,
conditions were just right
to build up huge thicknesses
of Black Shale source rocks
The world’s main oil deposits all formed in warm shallow seas
where plankton bloomed but bottom waters were deoxygenated
Presenter notes: Most of the Source Rocks that gave rise to our present day oil and gas fields were formed in the middle of the Mesozoic Era about 150 million years ago. At that time conditions were just right to build up huge thicknesses of Black Shale. On the one hand, the oceans were unusually warm, promoting vast plankton blooms. On the other hand, oxygen was mostly absent on the ocean floors so most of the plankton that settled on the bottom accumulated. There were no animals around to eat it up. The map on the left hand side shows what the Earth looked like 150 million years ago. The red circles show where the world’s main oil deposits were formed in warm, shallow, deoxygenated seas.
Ancient Earth

14. Origin (11): Source of North Sea Oil
© Ian and Tonya West
Black Shale
Presenter notes: A real example of a Black Shale that has formed a major oil deposit is the Jurassic Kimmeridge Clay. This is a 150 million year old shale that contains up to 50% organic matter. It stretches from Dorset in southern England right across to Norway. It was this Black Shale which was the main Source Rock for the North Sea oil and gas province.
Ancient Earth
The Kimmeridge Clay is a Black Shale with up to 50% organic
matter. It is the main source rock for the North Sea Oil & Gas Province

15. Exploration and Production (1): Oil Traps
Some rocks are permeable
and allow oil and gas to freely
pass through them
Other rocks are impermeable
and block the upward passage
of oil and gas
Where oil and gas rises up
into a dome (or anticline)
capped by impermeable rocks
it can’t escape. This is one
type of an Oil Trap.
Impermeable
Presenter notes: In the first practical we thought about the immense amount of time it takes to form oil and gas. Consequently, it is an extremely valuable resource and huge amounts of money are poured into trying to locate new oil and gas fields. In this section, we will investigate how reservoirs of oil and gas are discovered and how it eventually reaches the marketplace.
As we have already seen, once produced, oil and gas migrates out of its Source Rock and accumulates in overlying rocks. Some rocks like sandstone or limestone are permeable to oil and gas, which means that they can pass freely through them. Other rocks like clay or salt are impermeable, which means they block the upward passage of hydrocarbons.
One of the most common ways that oil and gas becomes trapped in pockets in the rock is where it is rises into a structural dome capped by impermeable rocks. The cap rocks prevent the oil and gas escaping upwards. The buoyancy of the less dense hydrocarbons in the pore waters prevent them from sinking back down. This is an example of an Oil Trap.
Optional exercise: An excellent additional exercise to get students thinking further about how Oil Traps form go to click on Earth-related Activities, and look under the Resource and Environment section.
Dome Trap
Permeable

16. Exploration and Production (3): Reservoir Rocks
The permeable strata in an oil trap
is known as the Reservoir Rock
Reservoir rocks have lots of
interconnected holes called pores.
These absorb the oil and gas like a
sponge
As oil migrates it fills up the pores
(oil-filled pores shown in black)
Presenter notes: The permeable rocks than contain oil and gas within the oil trap are known as the Reservoir Rock. Reservoir rocks have lots of interconnected holes called pores. These allow them to absorb the oil and gas like a sponge. The picture on the left shows a good reservoir rock with lots of pore spaces filled with water shown in blue. As we advance the slide, we see the pores gradually fill with oil. This rock can soak up a large amount of oil.
This is a highly magnified picture of
a sandy reservoir rock (water-filled
pores are shown in blue)
Earth Science World Image Bank Image #h5innl

17. Exploration and Production (4): Seismic Surveys
Drill here!
Presenter notes: We’ve just established what kind of structures tend to trap oil and gas in the Earth’s crust, but how do we locate potential traps underground? One technique is to use seismic surveys. In this technique, a Vibrator Truck fires shock waves into the ground. The shock waves pass through some rock layers and bounce off others. By recording how long it takes for the shock waves to arrive back at the surface allows geologist to build a picture of the internal structure of the rocks beneath their feet. An example of a seismic survey is shown in the diagram on the right. It reveals a large underground dome in the rocks. As we have seen domes often trap oil and gas so this may be a potential site to drill.
Background notes: The term seismic is derived from the Greek for “shake” (think earthquakes!)
Earth Science World Image Bank Image #h5inor
Earth Science World Image Bank Image #h5inpj
Seismic surveys are used to locate likely rock structures
underground in which oil and gas might be found
Shock waves are fired into the ground. These bounce off layers
of rock and reveal any structural domes that might contain oil

18. Exploration and Production (5): Drilling the well
Preparing to drill requires: 
Clearing the land and building access roads.
Have a source of water nearby, or drill a water well.
Digging a reserve pit for rock and mud that comes up in the drilling process.
Once an oil or gas prospect has been identified, a hole is drilled to assess the potential
The cost of drilling is very great.
On an offshore rig, it may cost
$10,000 for each meter drilled.
A company incurs vast losses
for every “dry hole” drilled
Presenter notes: A potential oil trap is called a Prospect. Once a prospect has been identified, the next stage is to drill a hole into the top of the trap to see if it contains oil and gas. It is incredibly expensive to a drill hole. On an offshore rig is may cost $10,000 for every metre drilled. So if you are going to drill a hole 5000 metres underground it’s going to cost you 20 million pounds/ 25 million dollars! Consequently geologists have to be pretty confident that they going to hit oil. If they drill too many ‘dry holes’ they will soon lose their jobs!
en.wikipedia.org/wiki/Image:Oil_platform.jpg

19. Exploration and Production (14): At the Refinery
Distillation
Plant
Oil refinery
Car fuel
Jet fuel
Presenter notes: At the refinery, the crude oil, which also contains a lot of gas, is processed. This involves separating out all the different hydrocarbons in the crude oil. To do this, the crude oil is heated in a furnace and then passed through a cooling tower. The method relies on the fact that different hydrocarbons have different boiling points. Consequently the heavy hydrocarbons like bitumen with high boiling points accumulate at the bottom of the cooling tower. Light hydrocarbons like paraffin with low boiling points accumulate near the top of the top. This process is known as fractional distillation. The different hydrocarbons have different uses. For example, bitumen is used to surface roads while paraffin is mostly used as aviation fuel.
Road tar
en.wikipedia.org/wiki/Image:Anacortes_Refinery_31911.JPG
en.wikipedia.org/wiki/Image:Crude_Oil_Distillation.png
Before it can be used crude oil must be refined.
Hydrocarbons can be separated using distillation, which
produces different fractions (or types) of oil and gas

20. Nuclear Energy

22. Fuel Pellets
The enriched UF6 is converted into UO2 which is then made into fuel pellets.
The fuel pellets are collected into long tubes. (~12ft).
The fuel rods are collected into bundles (~200 rods per bundle
~175 bundles in the core

23. Cladding
The material that the fuel rods are made out of is called cladding.
It must be permeable to neutrons and be able to withstand high heats.
Typically cladding is made of stainless steel or zircaloy.

25. Two common reactor types: Boiling Water Reactor and Pressurized Water Reactor.
BWR: P=1000 psi T=545F
PWR P=2250 psi T=600F
PWR is most common and is basis of marine nuclear power.

26. World Nuclear Power

27. Methane hydrate lattice
Gas hydrates
Methane hydrate lattice

28. Hydrates - What are they?
Gas Hydrates are solids formed from hydrocarbon gas and liquid water
They resemble wet snow and can exist at temperatures above the freezing point of water

30. 98% in ocean
2% on land
white dot = gas samples recovered
black dot = hydrate inferred from seismic imaging
dotted lines = hydrate-containing permafrost

31. using seismic-reflection profiles
Bottom Simulating Reflection (BSRs)
BSR – (bottom simulating reflection)
Interface between the free methane and the gas hydrates cause the BSR phenomena
This phenomena allows a quantification of the amount of hydrates present
Blanking –
The cementation effect of the hydrate causes a lower signal to be sent back to the ship.
Allows quantification of the hydrate zone.
Hydrate acoustical velocity
3.3 km/s. Which produce a strong signal. ( )

34. dissociating methane hydrate at sediment/water interface