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Formation Compressibility from Young's Modulus and Poisson's Ratio

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I am am working on a poroelastic model that couples Solid Mechanics and Darrcy's Law interfaces. Since formation compressibility is a function of Young's Modulus and Poisson's Ratio, does my model account for formation compressibility if I have input the values of Young's Modulus and Poisson's Ratio?


2 Replies Last Post 20.10.2022, 16:04 GMT-4
Ed Gonzalez COMSOL Employee

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Posted: 2 years ago 20.10.2022, 10:48 GMT-4

Hi Megan, the dried bulk modulus, K_dry, is taken from the Linear Elastic material node. If you enter the pair (E,nu), it is computed as described in the documentation https://doc.comsol.com/6.0/doc/com.comsol.help.comsol/comsol_ref_structuralmechanics.27.06.html#2330360

then, the formation compressibility is derived from Biot-Willis coefficient, alpha_B, as

C_f = alpha_B / (porosity * K_dry)

if you have data for the formation compressibility, enter the Biot-Willis coefficient as

alpha_B = C_f * porosity * K_dry

Cheers Ed

Hi Megan, the dried bulk modulus, K_dry, is taken from the Linear Elastic material node. If you enter the pair (E,nu), it is computed as described in the documentation https://doc.comsol.com/6.0/doc/com.comsol.help.comsol/comsol_ref_structuralmechanics.27.06.html#2330360 then, the formation compressibility is derived from Biot-Willis coefficient, alpha_B, as C_f = alpha_B / (porosity * K_dry) if you have data for the formation compressibility, enter the Biot-Willis coefficient as alpha_B = C_f * porosity * K_dry Cheers Ed

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Posted: 2 years ago 20.10.2022, 16:04 GMT-4

Thank you very much for your help, Ed! E, nu, porosity, and alpha_B are all applied to the materials in my model, so I should be set then. Thank you for linking the documentation reference!

Best.

Megan

Thank you very much for your help, Ed! E, nu, porosity, and alpha_B are all applied to the materials in my model, so I should be set then. Thank you for linking the documentation reference! Best. Megan

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