1. UK Shale gas: How much gas? How safe to extract?
Prof Mike Stephenson
British Geological Survey

2. Two main questions How much gas is there? How safe is it to extract?
Is it worth investing?
Is it worth thinking about risks and regulation if gas extraction never happens?
How safe is it to extract?
What are the main risks?
What science can be done to understand risks

3. How much gas is there? Reserve and resource
Resource figure -amount of gas in the ground (some of which might never be accessible)
Reserve figure -more sophisticated measure - amount of gas that you might be able extract given economics and other factors.
Recovery factor - proportion of the total gas resource that can be extracted and is often expressed as a percentage

4. How much gas is there? Variation in estimates and recovery factors
BGS approximate reserve estimates for DECC in tcf (150 BCM)
Advanced Resources (2011) which listed 97 tcf GIP and 20 tcf recoverable resources for the UK
Cuadrilla’s Lancashire licence their 1200 square kilometres licence area 200 tcf GIP
IGas acreage first estimate GIIP 800mmboe, then changed to c.1,600mmboe (millions barrels of oil equivalent tcf)
Eden Energy 7 licences in South Wales GIIP) – tcf ; Recoverable Volume – tcf of gas’.
Dart Energy Original Gas in Place (OGIP) of tcf

5. How safe to extract?

6. Main hazards/concerns
Earthquakes
Integrity of well casing and groundwater contamination
Radioactivity
Transportation of equipment, materials and wastes to and from the site;
Emissions to air
Noise
Large volumes of water for fracking
Surface spillages of chemicals and waste waters

7. Largest on 1 April
magnitude 2.3
felt >50 people

8. Comparison of signals
Comparison of signals from the 1 April and 27 May
Waveforms very similar, so similar origin
BGS concluded that the earthquakes were a direct consequence of the fluid injection during fracking

9. Management of future tremors
Cuadrilla commissioned reports on the tremors
DECC commissioned an expert group to look at the reports and make recommendations
Small pre-injection and monitoring before the main injection.
Growth direction should be monitored and monitoring system for automatic locations and magnitudes of any seismic events in near real-time.
Operations should be stopped and remedial action instituted, if events of magnitude 0.5 ML or above are detected.
UK Govt yet to make a decision and recommendations

10. Groundwater and rock stress baseline studies
How background methane is there in groundwater?
Which rocks are stressed already so should be avoided for fracking

11. Commons Select Committee Call for evidence on the ‘Impact of Shale Gas on Energy Markets’
What are the estimates for the amount of shale gas in place in the UK, Europe, and the rest of the world, and what proportion is recoverable?
Why are the estimates for shale gas so changeable?
What are the prospects for offshore shale gas in the UK Continental Shelf?
Should the UK consider setting up a wealth fund with the tax revenue from shale gas?
What have been the effects of shale gas on the LNG industry?
Could shale gas lead to the emergence of a single, global gas market?
What are the effects on investment in lower-carbon energy technologies?
What is the potential impact on climate change objectives of greater use of shale gas?

12. Conclusions
Resources and reserves estimates in Britain and Europe vary widely
This is affecting investor confidence; also policy makers aren't sure what to do….
Main British environmental concern has been earthquakes. Studies recommend ‘traffic light’ system to manage tremors
BGS has initiated groundwater and rock stress baseline studies
Commons Select Committee Call
14th Licensing Round

13. Extra slides for discussion?

14. Shale basics 1 mm Grey or black, soft Fine grained
What is shale gas?
Shale basics
Grey or black, soft
Fine grained
70% of the world’s surface rocks are sedimentary; 50% of those are shale.
Contain ~95 % of the organic matter in sedimentary rocks
1 mm

15. Where does the organic material come from?
What is shale gas?
Where does the organic material come from?
Land plant material and seawater algae collect in mud
Wouldn’t look like plants we know today
Older, deeper shale layer

16. Biological decay – biogenic methane
What is shale gas?
Shale buried
Biological decay – biogenic methane
Organic matter ‘cooked’ – thermogenic methane
Burial over millions of years
500 m
0 m
Old deep shale layer

17. Conventional and unconventional

18. Conventional and unconventional
sandstone
shale
Sand grain
gas
gas
Sand grain
0.25mm

19. Adsorbed gas and gas in pores
Conventional and unconventional
Adsorbed gas and gas in pores
Pore space gas
Adsorbed gas
calculation of gas in place per unit volume
We have to measure how much shale

20. Conventional and unconventional
Conventional: Trap
Cap rock
sandstone
Shale layer
Unconventional:
Continuous
accumulation

21. Conventional and unconventional
Fracking basics
Cracks the shale
High pressure water or nitrogen, bar (350 to 700 atmospheres)

22. Contamination from fracking? Osborn et al. 2011, PNAS
Studied:
Methane in shallow water wells in shale gas areas
measured methane content and δ13C

23. Molofsky et al. 2011
Not peer reviewed
Dec 2011

24. Molofsky et al. 2011

25. Blackpool seismicity
The Blackpool region - low seismicity even for the UK.
2.5 in km south-west of Blackpool.
number of smaller earthquake immediately offshore.
The magnitude 3.7 Ulverston earthquake 28 April 2009

26. How much gas is there? Complex terminology
Terms for resources and reserves
Term
Acronym
Summary
Resource
‘How much gas is in the ground’
Original gas in place
OGIP
Total volume of gas
Gas (initially) in place
GIIP/GIP
Ultimately recoverable
Total recoverable volume
Technically recoverable
Limited by technology
Economically recoverable
Limited by economics
Reserve
‘How much gas could be extracted’
Reserves
Total producible gas
Proved reserves 1P
Probability of reserves (proven)
Median figure of reserves 2P
Proven and probable
High figure of reserves 3P
Proved, probable and possible

27. Damage very unlikely to have been caused by earthquake
1. At least 50 small earthquakes occurred during and immediately after fracking stages. 2. The largest, on 1 April,  had a magnitude of 2.3 ML and was felt by over 50 people with a maximum intensity of 4 EMS. A magnitude 1.5 quake on 27 May was also felt. 3. The correlation in time and space with operations indicate that they were a direct consequence of the fluid injection during fracking. 4. Around 2000 m**3 of fluid was injected in each fracking stage and estimated injection pressures were as high as 70 MPa. 5. It is likely that the a similar pattern of injection in a nearby well could result in further earthquakes. 6. This highlights the need for an effective mitigation strategy linked to careful monitoring of further activity.
Damage very unlikely to have been caused by earthquake