The Potential for Earthquakes in the Quebec Utica Shale


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A presentation titled "The Stability of Fault Systems in the South Shore of the St. Lawrence Lowlands of Quebec - Implications for Shale Gas Development, presented members of the Society of Petroleum Engineers. This is a technical presentation that makes the case that while hydraulic fracturing does indeed cause small seismic events -- "earthquakes" -- those earthquakes are tiny and not detectable on the surface and cause no damage to underground or above ground structures.

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The Potential for Earthquakes in the Quebec Utica Shale

  1. 1. The Stability Of Fault Systems In The South Shore Of The St. Lawrence Lowlands Of Québec Implications For Shale Gas DevelopmentJohn Brodylo, Jean-Yves Chatellier,Guillaume Matton & Michel Rheault Copyright 2011, Society of Petroleum Engineers 1
  2. 2. Outline• Majority of Québec Utica shale gas exploration in south shore area of St. Lawrence Lowlands• Natural and man-made earthquakes in south shore• Tectonic domains, in-situ stress and fault styles• Fracture stimulation containment within shale gas target• Hydrofracturing Utica very unlikely to damage surface structures or shallow aquifers 2
  3. 3. Study Area St. Lawrence Québec Graben Québec CityOttawa-Bonnechere St. Lawrence Graben Lowlands Study Area Montréal 3
  4. 4. Earthquake• A sudden release of energy in the earths crust or upper mantle as a result of fault slip• Destructive at magnitudes of 5 and above• Minor earthquakes magnitude 2 to 5• Micro-earthquake is a very low intensity earthquake generally magnitude 2 or less 4
  5. 5. Earthquake Magnitude Comparison Perspective Limit Micro-earthquakes Minor-earthquakes Light Moderate of measurement Imperceptible rarely felt felt shaking damage by man 2 X Hiroshima Atomic Bomb Utica Shale Gas Frac 30 tons TNT Microseismic Average Québec event Earthquake 1 kg TNT Impact of Stick of Brick Dynamite Falling from Small 1 meterFirecracker-4 -3 -2 -1 0 1 2 3 4 5 6 Earthquake (Nuttli) Magnitude 5
  6. 6. Southern Québec Earthquakes Southern Québec Earthquakes Major Charlevoix Basement Faults Impact Crator Most Active Earthquake Regions of Southern Québec Québec City South Shore Shale Gas Exploration Areas Montréal US Border 6
  7. 7. Comparison of 10 Induced Seismic Events 9 Dams 8 Various 7 Global Manic 3 6 Waste Dam, Qc. 5 Water inj., 1975 TX. 2010Magnitude 4 3 Micro- Mine 2 seismic Collapse, event Geothermal 1 Barnett NY. 1994 US Army. Utica Various Shale Co. Fluid 0 Shale countries. Fracs. TX. Inj., 1962 Fracs. -1 Québec, -2 2008-2010 -3 -4 Event 7
  8. 8. Induced Seismic in Québec SM3 Reservoir Impoundment Induced - unspecified BlastingSt. Lawrence Lowlands 8
  9. 9. Risk?The Earth Sciences Division of the U.S.Department of Energy’s Lawrence BerkeleyNational Laboratory has studied inducedseismicity relating to oil and gas activityand to date hydraulic fracturing hasresulted in no known surface earthquakesfelt by manUpdate: Blackpool U.K. 2.3 M earthquake attributed to fluidinjection following hydraulic fracturing. Felt at surfacebecause of shallow focal depth, very unusual circumstances,no damage to building or aquifers 9
  10. 10. StratigraphyQueenston/LorraineSandstone, siltstone and shaleUtica Shale Gas targetQuartz/carbonate organic shalePotsdamRegional seismic reflector 10
  11. 11. 3 Major Tectonic Domains South Shore Utica Shale Gas Fairway Disturbed Domain Autochthonous Domain Grenville BasementConvergent margin Sediments Passive margin Sediments Granite & Metasediments U Ordovician Cambro-Ordovician Lorraine and Queenstown Shale gas target Image Modified from: TRIANGLE ZONES IN ACCRETIONARY WEDGES: EXAMPLES FROM THE QUÉBEC APPALACHIANS AND PHYSICAL MODELING Konstantinovskaya et al, AAPG Poster, 2010 11
  12. 12. Borehole Breakouts,Breakouts, Fractures Borehole Fractures and In-situ Stresses and In-situ Stresses • Bore hole break outs in the N direction of Shmin = 315 degrees sHMAX • Drilling induced fractures in Azimuth of Borehole direction of SHmax = 45 degrees breakouts Present day in-situ Stress Breakout SHmax borehole shmin Azimuth of principalNatural, Drilling Induced, stresses, s1 > s3 Drill Induced Shmin and Hydraulic Fracture Fractures 12
  13. 13. Autochthonous Domain Old Healed Fractures• Tensional passive margin Normal faulting From Rift Phase Strike Direction• Result of opening of the Iapetus Sea of Fractures• Hydraulic fractures propagate vertically• 488.3–443.7 million years old• Fractures in direction of SHmax = 38 degrees sv = s1 s1=sv s3 = shmin shmin sHMAX = s3s2 = sHmax = s2 In Situ sV>sHmax>shmin Stresses 13
  14. 14. Disturbed Domain Open Fractures • Compressional thrusting From Compressional • Hydraulic fractures in Phase direction of SHmax = 325 In Situ s3=svStresses degrees s1 = shMAX Strike Direction s2 = shmin sv = s3 of Fractures sHmax>shmin>sV sHMAX = s1 shmin = s2 14
  15. 15. Wrenching Present day in-situ Stress • Bore hole break outs in Breakout SHmax direction of Shmin = 315 degrees • Drilling induced fractures in Drill Induced Shmin direction of SHmax = 53 Fracture degrees In Situ Stresses sv = s2 s2=sv s3 = shmins1 = sHmax shmin sHMAX = s3 = s1 sHmax>sV>shmin 15
  16. 16. Fault Slip sn snCoulomb Stress = tb + m(sn + P) tb = shear stress P = pore pressure m = coefficient of friction sn = normal stress 16
  17. 17. Stress Affects on Completions Wrench Regime Thrust Regime Hydraulic fracturing stress state Pre-completion stress state More vertical fracturing sHmax >>sV hmin > sv sHmax s > shmin More horizontal fracturing Utica Pore Pressure sv sHMAX shmin20 40 60 80 100 MPa 17
  18. 18. Hydraulic Fracture Height Containment GR Hi Y Low • Contrasts in fracture toughness form barriers Lorraine • High Young’s modulus (Y)=Brittle=low toughness Schematic • Low Young’s modulus=Ductile=high Thrust toughness Ductile • Frac target a brittle zone with low toughness between ductile zonesUtica Shale BrittleGas Target Ductile • High toughness ductile zones are Brittle barriersTrenton • Thrust fault are barriers 18
  19. 19. Aquifer Micro-seismic Horizontal Shale Gas Well with Micro-seismic Events •Minimal vertical height growth •Formations above and below zone likely acting as barriers Microseismic events •No communication confined or propagation to to +/- 50 m of wellbore shallow aquifers.Utica 19
  20. 20. Surface Lineament Analysis South Shore Shale Gas Exploration Area (Study Area) There are a total of 14 minor > M2.5 earthquakes recorded in the South Shore Shale Gas exploration AreaMatton and Rheault 2011 20
  21. 21. Inset Map Québec City Cap-Rouge Earthquake Neuville Fault Trace at Potsdam Level St. LawrenceSeismic Line 78-824 Lowlands Shale Gas Fairway 18 Focal Depth kilometers 3.6 Earthquake magnitude Earthquake < M2.5 21
  22. 22. Summary• South shore shale gas exploration region is in stress relaxed state and less prone to fault reactivation• No correspondance between natural and man-made earthquakes and shallow faults in study area• In- situ stress, rock toughness, and thrust faults all act as barriers to vertical propagation of fractures and faults• Fracture stimulations are contained within shale gas target• Hydrofracturing is very unlikely to cause damage to shallow aquifers or surface structures 22
  23. 23. AcknowledgementsMichael Binnion Questerre Energy CorporationMarianne Molgat Talisman Energy IncGeoff Rait, - IEX Structural Geologist, Talisman EnergyScott McLellan, - IEX Geophysicist, Talisman EnergyHeather Davey Exploration Specialist Geology
  24. 24. Questions? 23