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© NERC All rights reserved UK Shale gas: How much gas? How safe to extract? Prof Mike Stephenson British Geological Survey

Mar 27, 2015



  • Slide 1

NERC All rights reserved UK Shale gas: How much gas? How safe to extract? Prof Mike Stephenson British Geological Survey Slide 2 NERC All rights reserved Two main questions How much gas is there? o Is it worth investing? o Is it worth thinking about risks and regulation if gas extraction never happens? How safe is it to extract? o What are the main risks? o What science can be done to understand risks Slide 3 NERC All rights reserved 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 Slide 4 NERC All rights reserved How much gas is there? Variation in estimates and recovery factors BGS approximate reserve estimates for DECC in 2010 - 5.3 tcf (150 BCM) Advanced Resources (2011) which listed 97 tcf GIP and 20 tcf recoverable resources for the UK Cuadrillas 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 - 9.23 tcf) Eden Energy 7 licences in South Wales GIIP) 34.198 tcf ; Recoverable Volume 12.799 tcf of gas. Dart Energy Original Gas in Place (OGIP) of 65.56 tcf Slide 5 NERC All rights reserved How safe to extract? Slide 6 NERC All rights reserved 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 Slide 7 NERC All rights reserved Largest on 1 April magnitude 2.3 felt >50 people Slide 8 NERC All rights reserved 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 Slide 9 NERC All rights reserved 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 Slide 10 NERC All rights reserved Groundwater and rock stress baseline studies How background methane is there in groundwater? Which rocks are stressed already so should be avoided for fracking Slide 11 NERC All rights reserved 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? Slide 12 NERC All rights reserved 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 14 th Licensing Round Slide 13 NERC All rights reserved Extra slides for discussion? Slide 14 NERC All rights reserved Shale basics Grey or black, soft Fine grained 70% of the worlds surface rocks are sedimentary; 50% of those are shale. Contain ~95 % of the organic matter in sedimentary rocks 1 mm What is shale gas? Slide 15 NERC All rights reserved Where does the organic material come from? Land plant material and seawater algae collect in mud Older, deeper shale layer What is shale gas? Slide 16 NERC All rights reserved 500 m 0 m What is shale gas? Shale buried Biological decay biogenic methane Organic matter cooked thermogenic methane Old deep shale layer Burial over millions of years Slide 17 NERC All rights reserved Conventional and unconventional Slide 18 NERC All rights reserved Sand grain gas 0.25mm shale sandstone Conventional and unconventional Slide 19 NERC All rights reserved 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 Conventional and unconventional Slide 20 NERC All rights reserved Shale layer sandstone Cap rock Conventional: Trap Unconventional: Continuous accumulation Conventional and unconventional Slide 21 NERC All rights reserved Fracking basics Cracks the shale High pressure water or nitrogen, 350-700 bar (350 to 700 atmospheres) Conventional and unconventional Slide 22 NERC All rights reserved Contamination from fracking? Osborn et al. 2011, PNAS Studied: Methane in shallow water wells in shale gas areas measured methane content and 13 C Slide 23 NERC All rights reserved Not peer reviewed Dec 2011 Molofsky et al. 2011 Slide 24 NERC All rights reserved Molofsky et al. 2011 Slide 25 NERC All rights reserved The Blackpool region - low seismicity even for the UK. 2.5 in 1970 5 km south-west of Blackpool. number of smaller earthquake immediately offshore. The magnitude 3.7 Ulverston earthquake 28 April 2009 Blackpool seismicity Slide 26 NERC All rights reserved How much gas is there? Complex terminology Terms for resources and reserves TermAcronymSummary Resource How much gas is in the ground Original gas in placeOGIPTotal volume of gas Gas (initially) in placeGIIP/GIPTotal volume of gas Ultimately recoverable Total recoverable volume Technically recoverable Limited by technology Economically recoverable Limited by economics Reserve How much gas could be extracted ReservesTotal producible gas Proved reserves1P Probability of reserves (proven) Median figure of reserves 2PProven and probable High figure of reserves3PProved, probable and possible Slide 27 NERC All rights reserved Damage very unlikely to have been caused by earthquake