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John Brodylo, Jean-Yves Chatellier,Guillaume Matton & Michel Rheault
The Stability Of Fault Systems
In The South Shore Of The
St. Lawrence Lowlands Of Québec
Implications For Shale Gas Development
Copyright 2011, Society of Petroleum Engineers 1
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
Ottawa-Bonnechere
Graben
St. Lawrence
Graben
St. Lawrence
Lowlands
Study Area Montréal
Québec
City
Study Area
Québec
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Earthquake
• A sudden release of energy in the earth's 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
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Perspective
1 kg TNT
Stick of
Dynamite
2 X Hiroshima
Atomic Bomb
-3 -2 -1 0 3 4 5 2 1
Earthquake (Nuttli) Magnitude
-4 6
Micro-earthquakes
Imperceptible
by man
Minor-earthquakes
rarely felt felt
Light
shaking Moderate
damage
Limit
of measurement
Small
Firecracker
Impact of
Brick
Falling from
1 meter
Utica Shale
Gas Frac
Microseismic
event
30 tons TNT
Average Québec
Earthquake
Earthquake Magnitude Comparison
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Southern Québec Earthquakes
Major
Basement Faults
Québec City
Montréal
Most Active Earthquake
Regions of Southern Québec
Charlevoix Impact Crator
South Shore
Shale Gas
Exploration
Areas
US Border
Southern Québec Earthquakes
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Comparison of Induced Seismic Events
Mag
nit
ud
e
-3
-2
-1
0
3
5
2
1
-4
6
4
9
8
7
10
Event
Geothermal Various
countries.
Barnett Shale
Fracs. TX.
Mine Collapse, NY. 1994
Manic 3 Dam, Qc.
1975
Dams Various Global
Micro-seismic event Utica Shale Fracs.
Québec, 2008-2010
Waste Water inj., TX. 2010
US Army. Co. Fluid Inj., 1962
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St. Lawrence
Lowlands
Induced Seismic in Québec
SM3 Reservoir Impoundment
Induced - unspecified
Blasting
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Risk?
The Earth Sciences Division of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory has studied induced seismicity relating to oil and gas activity and to date hydraulic fracturing has resulted in no known surface earthquakes felt by man
Update: Blackpool U.K. 2.3 M earthquake attributed to fluid
injection following hydraulic fracturing. Felt at surface because of shallow focal depth, very unusual circumstances, no damage to building or aquifers
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Stratigraphy
Queenston/Lorraine
Sandstone, siltstone and shale
Utica Shale Gas target
Quartz/carbonate organic shale
Potsdam
Regional seismic reflector
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Image Modified from: TRIANGLE ZONES IN ACCRETIONARY WEDGES: EXAMPLES FROM THE QUÉBEC APPALACHIANS AND PHYSICAL MODELING
Konstantinovskaya et al, AAPG Poster, 2010
Autochthonous Domain Passive margin Sediments
Cambro-Ordovician Shale gas target
Grenville Basement Granite & Metasediments
Disturbed Domain Convergent margin Sediments
U Ordovician Lorraine and Queenstown
3 Major Tectonic Domains
South Shore Utica Shale Gas Fairway
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Borehole Breakouts, Fractures and In-situ Stresses
• Bore hole break outs in the direction of Shmin = 315 degrees
• Drilling induced fractures in direction of SHmax = 45 degrees
sHMAX
shmin
principal stresses, s1 > s3
Azimuth of Borehole breakouts
Azimuth of Natural, Drilling Induced,
and Hydraulic Fractures
borehole
N
Shmin
Breakout SHmax
Present day in-situ Stress
Drill Induced
Fracture
Borehole Breakouts, Fractures and In-situ Stresses
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sv = s1
sHMAX = s2
shmin = s3
s3 = shmin
s2 = sHmax
In Situ Stresses
s1=sv
sV>sHmax>shmin
Old Healed Fractures From Rift Phase
Strike Direction
of Fractures
Autochthonous Domain
• Tensional passive margin Normal faulting
• Result of opening of the Iapetus Sea
• Hydraulic fractures propagate vertically
• 488.3–443.7 million years old
• Fractures in direction of SHmax = 38 degrees
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s1 = shMAX
s2 = shmin
In Situ Stresses
s3=sv
sHmax>shmin>sV
Open Fractures From
Compressional Phase
Strike Direction
of Fractures
Disturbed Domain
• Compressional thrusting
• Hydraulic fractures in direction of SHmax = 325 degrees
shmin = s2
sHMAX = s1
sv = s3
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s3 = shmin
s1 = sHmax
In Situ Stresses
s2=sv
sHmax>sV>shmin
Shmin
Breakout SHmax
Present day in-situ Stress
Drill Induced
Fracture
• Bore hole break outs in direction of Shmin = 315 degrees
• Drilling induced fractures in direction of SHmax = 53 degrees
Wrenching
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Wrenching
shmin = s3
sv = s2
sHMAX = s1
sn
sn
Coulomb Stress = tb + m(sn + P)
tb = shear stress
m = coefficient of friction sn = normal stress
P = pore pressure
Fault Slip
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20 40 60 80 100 MPa
Pore
Pressure
shmin
sHMAX
sv
sHmax > shmin > sv
Wrench Regime
Pre-completion stress state More vertical fracturing
sHmax > sV > shmin
Thrust Regime
Hydraulic fracturing stress state More horizontal fracturing
Stress Affects on Completions
Utica
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• Contrasts in fracture toughness form barriers
• High Young’s modulus
(Y)=Brittle=low toughness • Low Young’s modulus=Ductile=high
toughness • Frac target a brittle zone with low
toughness between ductile zones
• High toughness ductile zones are barriers
• Thrust fault are barriers
Hydraulic Fracture Height Containment
Lorraine
Utica Shale
Gas Target
Trenton
GR Y Hi Low
Ductile
Ductile
Brittle
Brittle
Schematic
Thrust
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Micro-seismic
Microseismic events confined
to +/- 50 m of wellbore
Aquifer
Utica
Horizontal Shale Gas Well with Micro-seismic Events
•Minimal vertical height growth
•Formations above and below zone likely acting as barriers
•No communication or propagation to shallow aquifers.
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There are a total of 14 minor >
M2.5 earthquakes recorded
in the South Shore Shale Gas
exploration Area
Surface Lineament Analysis
Matton and Rheault 2011
South Shore
Shale Gas
Exploration
Area
(Study Area)
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Inset Map
St. Lawrence
Lowlands
Shale Gas
Fairway
Québec City Cap-Rouge Earthquake
Neuville Fault Trace
at Potsdam Level
18 3.6
Focal Depth kilometers Earthquake magnitude
Earthquake < M2.5
Seismic Line 78-824
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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
Michael Binnion Questerre Energy Corporation
Marianne Molgat Talisman Energy Inc
Geoff Rait, - IEX Structural Geologist, Talisman Energy
Scott McLellan, - IEX Geophysicist, Talisman Energy
Heather Davey Exploration Specialist Geology
Acknowledgements
Questions?
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