how do fossil fuels form and how are they extracted?

38
How do fossil fuels form and how are they extracted?

Upload: raphael-hardy

Post on 30-Dec-2015

25 views

Category:

Documents


4 download

DESCRIPTION

How do fossil fuels form and how are they extracted?. 1. What is oil?. 2. How does it form?. Oil ‘Black Gold’. 3. What rocks and structures is it f ound in?. 4 . How can geologists find it?. 5 . What are the problems with its e xtraction and use?. 1. What is oil?. C. C. C. C. C. - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: How do fossil fuels form and how are they extracted?

How do fossil fuels form and how are they extracted?

Page 2: How do fossil fuels form and how are they extracted?

Oil‘Black Gold’

• 1. What is oil? •2. How does it form?

• 3. What rocksand structures is itfound in?

• 5. What are the problems with itsextraction and use?

• 4. How can geologists find it?

Page 3: How do fossil fuels form and how are they extracted?

Crude Oil

Hydrocarbon

• 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 chain of carbonmolecules.

H

C

C

C

C

C CC C1. What is oil?

Page 4: How do fossil fuels form and how are they extracted?

Petroleum

Petra = Rock Oleum = Oil

Contains:

• Crude Oil (Liquid)

• Natural Gas (Gas)

• Asphalt (Solid)

1. Why it classed as a non-renewable resource?

2. Why is petroleum sometimes called a fossil fuel?

Page 5: How do fossil fuels form and how are they extracted?

What is oil (origin)?

en.wikipedia.org/wiki/Image:Ceratium_hirundinella.jpg

• Most oil and gas starts life as microscopic organisms called plankton that live in the ocean.

Plant plankton Animal plankton

10,

000

of t

hese

bug

sw

ould

fit

on a

pin

head

!

Page 6: How do fossil fuels form and how are they extracted?

2. How does it form (Oil Formation)

• Remains of microscopic plankton in ocean (Float on surface)

• When die sink in water column and accumulate on sea bed

• In a low energy anoxic environment (prevent breakage and decay) • Anaerobic bacteria

produce partial decay to form organic mud called saropel• Further burial causes compaction and increase in temperature with depth

• Burial, occur to cause fine grained organic rich source rock e.g. Shales

• Oil maturation to form kerogen then petroleum (‘Oil Window’ 50-200oC)

Petroleum

PlanktonDie,Sink &Accumulateon SF

Low energy& anoxicenvironment

Anaerobicbacteriaformsaropel

Burial toform finegrained shales.

Further burial = compaction & inc. T.

Maturationto formkerogen

Further maturation

Page 8: How do fossil fuels form and how are they extracted?

3. What rocks is it found in?Reservoir Rocks

‘Once formed oil migrates into reservoir rocks where it collects’

• Poorly cemented sandstones are good reservoir rocks as is chalk and limestone

Add labels to a sketch to explain whysandstone is such a good reservoir?

Porous: Large pores and higher porosity means more storage space

Highly Permeable: pores must be interconnected to allow migration and then extraction of oil and gas

Well rounded increases porosity

Poorly cemented: Allows interconnectivity of grainsWell sorted: > Porosity

Page 9: How do fossil fuels form and how are they extracted?

3. What rocks is it found in?Cap Rocks

‘’Need to be impermeable to stop the further migration of theoil and gas upwards and escaping / seeping out at surface’

Make a list of potential cap rocks

• Fine grained sedimentary rocks e.g. Clay, mudstone and Shale!

• Crystalline Sedimentary e.g. Evaporites (Halite)

Page 10: How do fossil fuels form and how are they extracted?

3. What Structures is it found in?Oil Traps

‘a trap is needed to allow the accumulation of economic quantities ofhydrocarbons’

• 4 Types:• Unconformity• Fault• Salt dome• Anticline

Page 11: How do fossil fuels form and how are they extracted?

Oil and Gas are always horizontal There must always be a:

• Source rock• Reservoir

rock• Cap rock• Structural

Trap

Page 13: How do fossil fuels form and how are they extracted?

Explanation of why oil collected:

Explanation of why oil collected:

Explanation of why oil collected:

A) Anticline B) Fault

C) Salt Dome D) Unconformity

Task:1. Label the source rock, cap rock and reservoir rock of each.2. Shade in colour the oil and gas3. Explain why the oil has collected in this type of trap

Explanation of why oil collected:

Page 14: How do fossil fuels form and how are they extracted?

Task:1. Label the source rock, cap rock and reservoir rocks2. Shade in colour 3 locations where may accumulate oil and gas

Page 15: How do fossil fuels form and how are they extracted?

UK Oil and Gas field Map

Oil and Gas

Gas Only

Page 17: How do fossil fuels form and how are they extracted?
Page 18: How do fossil fuels form and how are they extracted?

Drill here!

Salt dome Found

Page 19: How do fossil fuels form and how are they extracted?

Gravity Surveys

Page 20: How do fossil fuels form and how are they extracted?

Exploration Drilling

Page 21: How do fossil fuels form and how are they extracted?

5. What are the problems with its recovery and use?

Recovery

• Ecological impacts e.g. spills while drilling• e.g. Gulf of Mexico 2010.

• Explosions and fires on rigs off shore

• Spills during transport

Use

• Unsustainable (finite)

• Pollution (acid rain)

• Releases CO2

• Which causes climate change

Page 22: How do fossil fuels form and how are they extracted?

Coal

• 1. What is coal? •2. How does it form?

• 3. What rocksand structures is itfound associated with?

• 5. What are the problems with itsextraction and use?

• 4. How can geologists find it?

Page 23: How do fossil fuels form and how are they extracted?

How is coal formed?1. Plant matter accumulates at the bottom of a body of water in a swamp.

Page 24: How do fossil fuels form and how are they extracted?

How is coal formed?

http://www.minepermits.ky.gov/NR/rdonlyres/06BC5AA8-EF18-4762-8585-C517CD57E71B/0/Ed_coal_formation.jpg

2. The plant matter is protected from oxidisation and biodegradation by mud or acidic water (anoxic conditions)

Page 25: How do fossil fuels form and how are they extracted?

How is coal formed?

http://www.minepermits.ky.gov/NR/rdonlyres/06BC5AA8-EF18-4762-8585-C517CD57E71B/0/Ed_coal_formation.jpg

3. Over time, the plant matter is changed by heat and pressure to create a solid material.

Page 26: How do fossil fuels form and how are they extracted?

How is coal formed?

http://www.minepermits.ky.gov/NR/rdonlyres/06BC5AA8-EF18-4762-8585-C517CD57E71B/0/Ed_coal_formation.jpg

4. The coal grade increases from peat to lignite to bituminous coal to anthracite with time, increased pressure and temperature.

Page 27: How do fossil fuels form and how are they extracted?
Page 28: How do fossil fuels form and how are they extracted?

Coal Rank ComparisonIncreasing Rank

Type of Coal PEAT LIGNITE SUB-BITUMINOUS BITUMINOUS ANTHRACITE

Carbon Content %

15 25 45 56 95

Energy Content Mj/Kg

10 30 40 60 65

Which type of coal do you think is the most desirable to mine for the energy Industry and why?

Which type causes the lowest pollution?

Page 29: How do fossil fuels form and how are they extracted?

Where are the British

Coalfields?

Page 30: How do fossil fuels form and how are they extracted?

Why was the South Wales Coalfield (Glamorgan) So important?

Page 31: How do fossil fuels form and how are they extracted?
Page 32: How do fossil fuels form and how are they extracted?

1. What type of fold structure has preserved the Upper coal measures of South Swansea?

2. Explain how this structure allowed important deposits to be preserved (use a sketch)

Page 33: How do fossil fuels form and how are they extracted?
Page 34: How do fossil fuels form and how are they extracted?

Features of the formation of fossil fuels that make exploitation difficult

Slow processes of fm.

Deep burrial

Young oil is viscous Young lignite has low energy density.

Widely dispersed and often inaccessible areas e.g. coal in

Antarctica.

Page 35: How do fossil fuels form and how are they extracted?

Explanation of why oil collected:

Explanation of why oil collected:

Explanation of why oil collected:

A) Anticline B) Fault

C) Salt Dome D) Unconformity

Task:1. Label the source rock, cap rock and reservoir rock of each.2. Shade in / colour in the oil and gas3. Explain why the oil has collected in this type of trap

Explanation of why oil collected:

Page 36: How do fossil fuels form and how are they extracted?

Task:1. Label the source rock, cap rock and reservoir rocks2. Shade in colour 3 locations where may accumulate oil and gas

Page 37: How do fossil fuels form and how are they extracted?
Page 38: How do fossil fuels form and how are they extracted?

Petroleum

• Remains of microscopic plankton in ocean (Float on surface)

• When die sink in water column and accumulate on sea bed

• In a low energy anoxic environment (prevent breakage and decay)

• Anaerobic bacteria produce partial decay to form organic mud called saropel

• Further burial causes compaction and increase in temperature with depth

• Burial, occur to cause fine grained organic rich source rock e.g. Shales

• Oil maturation to form kerogen then petroleum (‘Oil Window’ 50-200oC)

Options

Oil Formation