Seismic geomechanics
Seismic geomechanics
Elastic properties of the earth
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What is Seismic? 6HLVPLF ³Of or relating to earthquakes or other vibrations of the earth DQGLWVFUXVW´ Oxford Dictionary)
Seismology = The study of the vibration of the earth 0RVWRI\RXU³JHRSK\VLFLVWV´DUHDFWXDOO\³VHLVPRORJLVWV´ because they primarily use seismic data, which is a measurement of the vibration of the earth.
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What is geomechanics? Geo = Earth 0HFKDQLFV ³0HFKDQLFVLVthe study of the motion of material objects´ Cliffs Notes) GeoMechanics = The study of the motions of the earth Seismologist studies the vibration (motion) of the earth
? 6HLVPRORJLVWVVKRXOG³JHW´JHRPHFKDQLFV
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Elastic Rock Properties o Compressibility (C)
Compliance to change in volume (stress is perpendicular)
C 'v/v / S Bulk Modulus (Incompressibility)
N 1/C
Change in volume
Resistance to change in volume o Shear Modulus ( P) Resistance to change in shape (stress is parallel) No change in volume
73 The Essentials of Rock Physics for Seismic Amplitude Interpretation; ikon Science
Elastic Rock Properties: Bulk Modulus ( N ) 0DWHULDO¶VUHVSRQVHWRXQLIRUPSUHVVXUH
High Compressibility= Low Bulk Modulus
Bulk Modulus is also known as incompressibility, which is the inverse of compressibility, N = 1/C. Examples: Shale: 15 GPa Quart SS: 23 GPa Limestone:40 GPa Low Compressibility=High Bulk Modulus
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Elastic Rock Properties: Shear Modulus ( P ) 0DWHULDO¶VUHVSRQVHWRVKHDULQJVWUDLQV
Rigidity is the resistance to forces that cause a change in shape but not volume High Rigidity ± High Shear Modulus
Examples: Shale: 6 Gpa Quartz SS: 13 GPa Limestone: 21 GPa
Low Rigidity ± Low Shear Modulus
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Elastic properties of the earth
70
What is Seismic? 6HLVPLF ³Of or relating to earthquakes or other vibrations of the earth DQGLWVFUXVW´ Oxford Dictionary)
Seismology = The study of the vibration of the earth 0RVWRI\RXU³JHRSK\VLFLVWV´DUHDFWXDOO\³VHLVPRORJLVWV´ because they primarily use seismic data, which is a measurement of the vibration of the earth.
71 71
What is geomechanics? Geo = Earth 0HFKDQLFV ³0HFKDQLFVLVthe study of the motion of material objects´ Cliffs Notes) GeoMechanics = The study of the motions of the earth Seismologist studies the vibration (motion) of the earth
? 6HLVPRORJLVWVVKRXOG³JHW´JHRPHFKDQLFV
72
Elastic Rock Properties o Compressibility (C)
Compliance to change in volume (stress is perpendicular)
C 'v/v / S Bulk Modulus (Incompressibility)
N 1/C
Change in volume
Resistance to change in volume o Shear Modulus ( P) Resistance to change in shape (stress is parallel) No change in volume
73 The Essentials of Rock Physics for Seismic Amplitude Interpretation; ikon Science
Elastic Rock Properties: Bulk Modulus ( N ) 0DWHULDO¶VUHVSRQVHWRXQLIRUPSUHVVXUH
High Compressibility= Low Bulk Modulus
Bulk Modulus is also known as incompressibility, which is the inverse of compressibility, N = 1/C. Examples: Shale: 15 GPa Quart SS: 23 GPa Limestone:40 GPa Low Compressibility=High Bulk Modulus
74
Elastic Rock Properties: Shear Modulus ( P ) 0DWHULDO¶VUHVSRQVHWRVKHDULQJVWUDLQV
Rigidity is the resistance to forces that cause a change in shape but not volume High Rigidity ± High Shear Modulus
Examples: Shale: 6 Gpa Quartz SS: 13 GPa Limestone: 21 GPa
Low Rigidity ± Low Shear Modulus
75
