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

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 www.oilexploration.ir

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

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 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 - 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

How safe to extract?

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

Largest on 1 April magnitude 2.3 felt >50 people

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

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

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

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?

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

Extra slides for discussion?

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

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

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

Conventional and unconventional

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

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

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

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

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

Molofsky et al. 2011 Not peer reviewed Dec 2011

Molofsky et al. 2011

Blackpool seismicity 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

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

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