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Dr Liam Herringshawlgh865@hotmail.com

Earth's Energy Systems

Class 3: Oil & Gas

Origins

Organic matterBurial generates hydrocarbons by

'cracking'Depth/temperature:

– Oil window– (60–120 'C)– Gas window– (>100 'C)

Methane = CH4

KerogensType I – Sapropelic Cyanobacteria, freshwater algae

= oil

Type II – Planktonic Mostly marine, mixed oil/gas

Type III – Humic Terrestrial plant matter,

produces gas

Conventional hydrocarbons

UK Oil & Gas - onshore

UK Oil & Gas - offshore

Gas discoveries late 1960sOilfields 1970s onwards

The case for oil & gas

Your arguments in favour(with reference/s)

The case against oil & gas

Your arguments in opposition(with reference/s)

The economics of oil

Increasingly expensive, increasingly imported

Unconventional hydrocarbons

Britain for shale?

(Figure from DECC report)

UK prospects?

UK targets

CarboniferousNW England

JurassicSE England

Carboniferous

(Image from BGS report)

Jurassic

* BGS/DECC currently investigating resources* Durham/Newcastle – new NERC catalyst grant

(Image from BGS report)

Fracking seismicity

Does fracking cause earthquakes?

Yes

Professor Pete Styles, Keele University

Should we be worried?

Not really

Professor Pete Styles, Keele University

Induced Seismicity

Redrawn from Davies et al. (2012)

Mitigation techniquesStructural geology:–Understand tectonic history–Avoid unidirectional weaknesses

Does fracking pollute aquifers?

From 'Gasland'

Fracture propagation

Redrawn from Davies et al. (2012)

<1% risk of vertical frack >350m

600m minimum safeseparation distance

Fracking fluids?

4000 holes in Blackpool Lancashire?

Well density

Carboniferous–Bowland Shale thicker than US shales–1300 Tcf resources?–5% recoverable = 65 Tcf–2.5-5 Bcf per well–= 13,000-26,000 wells–10 wells per pad–= 1300-2600 pads

But many uncertainties

Well integrity

Leakage rate?Is UK well-prepared?

24 Jan 2013

23 Jan 2013

Consensus?

Resources

www.refine.org.uk

Research briefsTranslationsVideosNews

Next week: Nuclear

FOR – make an argument in favour of nuclear power

AGAINST – make an argument against

Is nuclear part of our future energy mix?