Presentation on theme: "∂ Some ideas…. Petroleum Geologist Mining, minerals & resources Use geology and geophysics to locate hydrocarbons Work on drilling platforms to extract."— Presentation transcript:
∂ Some ideas…. Petroleum Geologist Mining, minerals & resources Use geology and geophysics to locate hydrocarbons Work on drilling platforms to extract oil and gas Work all over the world, on-and off-shore Extract minerals from the Earth Gold, coal, metals, salts, more… Opportunities globally
∂ More ideas… Environmental Geologist/Geochemist Volcanologist Study how humans affect our environment Understand the changing climate Prevent and mitigate environmental damage Understand and witness nature’s most violent events Travel: Iceland, Japan, USA and more… Work to predict eruptions avoid disasters
∂ My time line Maths; Physics; Geog South Africa with Anglo America (Mining Engineer) Degree in Geology - Reading summer jobs….whatever paid (brick factory, mcvities, boots, etc etc) PhD Geology - Edinburgh summer job in oil industry experience 5 month temp geology job in Venezuela 1995 Mobil oil2003 Cardiff U Snr. Lect 2006 Durham Professor 2014 summer job in oil industry experience
∂ Electricity and Gas Where does our electricity come from? How do we use gas?
∂ Shale Gas and Fracking Prof. Richard Davies
∂ What does the term “Fracking” mean to you? What words come to mind when you think of Fracking? Do you think fracking should take place in the UK? Questions:
∂ Some UK shales: Edale
∂ Some UK shales: Craster
∂ What is Shale? Fine grained, organic rich mudstones: 4 main components: Clay Quartz silt Organic matter (dead plants and animals) Calcium carbonate (shells of dead sea creatures) Most common rock type on Earth Gas forms in small holes (pore spaces) in the shale
∂ What is Fracking? Shales are impermeable, trapped gas can’t flow out by itself Rocks must be cracked (fractured) to let gas escape Horizontal drilling is used to reach more rock Water used to crack the shale, sand holds cracks open Process is new to Europe, but well established in USA
∂ What is Fracking? Wells drilled vertically up to 3 km (length of around 30 football pitches) and then drilled horizontally Drilling and fracking takes about 1 month. A well will produce for years. Preese Hall, Lancashire. 1 st and only well fracked in UK. Photo: BBC News Lancashire
∂ Fracking is controversial: why?
∂ Is It safe? Or
∂ Earthquakes Fracking can cause minor earthquakes (tremors) Fractures and fluids reactivate old geological faults Very few cases recorded Less severe than other man-made earthquakes Q: Is this a serious risk?
∂ Water Pollution Claims that fracking will contaminate aquifers (the rocks that contain drinking water) Many reports of methane and chemical pollution in USA But Fractures not large enough to reach aquifers In USA leak due to natural processes and well integrity
∂ Can Wells Leak? During production (most of the time) well head (christmas tree) in place. Abandonment – well head cut and welded shut Watson and Bachu 2009 Well Head Casing and Cement Abandoned Welded Well Head Well Pad
∂ Can Wells Leak? Gas/fluids can reach surface through wellbores Wells are sealed with metal casing and cement – but this degrades over time Many older wells have poor protection In Pennsylvania (USA), >6% wells have integrity or barrier failures Abandoned wells not currently monitored in UK
∂ Why could shale gas be important? UK imports ~60% of the gas we use UK relies on energy imports Shale could help UK become less dependent on imports Lower energy prices? However: Little known about UK resources Much public opposition/gaps in scientific knowledge UK would require many 1000s wells
∂ Summary Fracking itself very unlikely cause of aquifer contamination. 100,000s of fracking operations and 3 cases of felt seismicity but important to avoid critically stressed faults. Databases and publications show that well leak is possible. Monitoring will be important. Uncertain what effect shale gas would have on UK.
∂ Questions: Do you think fracking should take place in the UK?