strain tensor - john t. fosterjohnfoster.pge.utexas.edu/pge334-resgeomechanics/sl… · ·...
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Strain tensor
Volumetric strain
Material constants for isotropic materials
Young's modulus
Bulk modulus
Shear Modulus
Poisson's ratio
Typical Young's modulus values
© Lama, R. D., and V. S. Vutukuri. . Monograph. 1978.)
HANDBOOK ON MECHANICAL PROPERTIES OF ROCKS-TESTING TECHNIQUES AND RESULTS. VOLUME 2
Typical Poissons' modulus values
© Lama, R. D., and V. S. Vutukuri. . Monograph. 1978.)
HANDBOOK ON MECHANICAL PROPERTIES OF ROCKS-TESTING TECHNIQUES AND RESULTS. VOLUME 2
Generalized Hooke's law
For isotropic materials
Relationships between constants
Relationships between constants (contd.)
Siesmic wave velocity
Poroelasticity
Poroelasticity Assumptions1. There is an interconnected pore system uniformly saturated with �uid.2. The total volume of the pore system is small compared to the volume of the rock.3. The pore pressure, the total stress acting on the rock externally, and the stresses acting
on the grains are statistically de�ned.
E�ective stressTerzaghi de�nition
"Exact" e�ective stress
is called Biot's coe�cient
Biot's coe�ceint
For sand
For rocks
Biot's coe�cient (cont.)
© Cambridge University Press (Fig. 3.5c, pp. 69)Zoback, Reservoir Geomechanics