Fracking for Shale Gas Risks and Concerns. Professor Robert Mair

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1 Fracking for Shale Gas Risks and Concerns Professor Robert Mair CUEN Annual Conference Jesus College 9 th June 2014

2 What is shale and what is shale gas? Shale is a very fine grained sedimentary rock formed from clay, silt or mud and is one of the most abundant sedimentary rock types in the Earth s shallow crust Shale gas is mostly composed of methane (CH 4 ), otherwise known as natural gas, and can be recovered from shale using hydraulic fracturing i.e. fracking A shale outcrop in the UK Source: British Geological Survey

3 Public perceptions

4 Key concerns Seismicity Small earthquakes occurred in Blackpool area April May 2011 associated with hydraulic fracturing Environmental Widespread concern in USA following incidents of contamination of groundwater and drinking water supplies

5 Report can be downloaded from gas extraction/report/ or

6 Royal Academy of Engineering and The Royal Society Report on Shale Gas extraction in the UK Independent review of the risks undertaken for the UK Government Chief Scientific Adviser, Sir John Beddington: Committee Members: Professor Robert Mair CBE FREng FRS, University of Cambridge (Chairman) Professor Michael Bickle FRS, University of Cambridge Dr Dougal Goodman OBE FREng, The Foundation for Science and Technology Dr John Roberts CBE FREng, Chairman, Royal Bank of Canada (Europe) Professor Richard Selley, Imperial College Professor Zoe Shipton, University of Strathclyde Professor Hywel Thomas FREng FRS, University of Cardiff Professor Paul Younger FREng, University of Glasgow Dr Dougal Goodman

7 Terms of reference Requested by Sir John Beddington FRS, Government Chief Scientific Adviser Independent review of scientific and engineering evidence What are major risks associated with hydraulic fracturing to extract shale gas? geological, ie seismicity environmental, eg groundwater contamination

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9 Shale Gas Exploration in USA Drilling site Shale gas exploration in Wyoming (Jonah Field) J. SARTORE/National Geographic Stock

10 Density of Drilling Operations In the USA: 3.5 platforms / km 2 On average 6 wells per platform platforms km (potentially longer) Source: Wood et al., 2011; University of Manchester

11 Shale Gas Production Production site Source: Caudrilla Resources Wellhead

12 Environmental Risks: Possible causes of groundwater contamination Surface operations: inadequate treatment of wastewater or spillage of chemicals Faulty well construction Fracture propagation or migration of solutes or methane through ground

13 Well integrity Importance of preventing shale gas from leaking out of the well by isolating it from other subsurface formations A series of holes ( wellbores ) of decreasing diameter and increasing depth drilled and lined with steel casing, joined together to form continuous strings of casing Cement provides structural support as well as isolation of different rock formations pumped down wellbore and up between casing and rock until it reaches surface

14 Briskin (2012)

15 Briskin (2012)

16 Passive seismic reservoir monitoring: Microseismicity Monitoring stress state of the reservoir. hydrocarbon migration, fluid pressure, borehole breakout. Many applications from conventional earthquake seismology. Relatively new oilfield technology. P S

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18 Comparisons of fracture growth and depth of overlying water sources (aquifers or water wells) (Fisher and Warpinski, 2012)

19 Seismicity in the UK

20 Coal mining < 4M L Fracking < 3 M L (Green, Styles and Baptie, 2012)

21 Summary of findings (I) Hydraulic fracturing ( fracking ) can be managed effectively in the UK as long as operational best practices are implemented and robustly enforced through regulation Strong regulation and robust monitoring systems must be put in place and best practice strictly enforced if the Government is to give the go ahead to further exploration

22 Summary of findings (II) Seismicity (or earth tremors) induced by hydraulic fracturing is likely to be of a smaller magnitude than the UK naturally experiences or than is related to coal mining activities themselves low by world standards The risks of contamination of aquifers from fractures is very low provided that shale gas extraction takes place at depths of many hundreds of metres

23 Key recommendations (I) Baseline surveys and monitoring for contamination throughout lifetime of operation Strengthening the UK s regulators, including providing additional resources as needed Allocating lead responsibility for regulation of shale gas extraction to a single regulator Strengthening the system of well inspections to ensure well designs are considered not only from a health and safety perspective but also from an environmental perspective

24 Key recommendations (II) Appropriate well integrity tests as standard practice Mandating and enforcing Environmental Risk Assessments for all shale gas operations, which should be submitted to the regulators for scrutiny Ensuring robust monitoring of methane in groundwater, seismicity and methane leakages before, during and after hydraulic fracturing Establishing integrated management processes to ensure water is used sustainably and to minimise wastes

25 Existing onshore conventional oil and gas wells in the UK Over past 30 years more than 2,000 onshore wells have been drilled in UK, around 200 of which have been fracked to enhance recovery of oil or gas

26 Additional considerations Exploratory activities uncertainties addressed through robust monitoring systems Greater uncertainty about scale of production activities should future shale gas industry develop how might risks scale up? Climate risks associated with extraction and use of shale gas Public acceptability in context of UK s energy, climate and economic policies

27 Summary Hydraulic fracturing of wells has been undertaken for many years The risks are understood and can be effectively managed with best practice and robust regulation UK reporting of US experience has sensitised local communities to believe that the risks may be greater in the UK than they actually are Public perception of risks can be quite different from the operator s perspective an effective two way dialogue is essential at a local, regional and national level to avoid outrage