The rock volume
is split into three major components: effective pore volume , shale volume and rock martix : LaTeX Math Block |
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anchor | Omega_R |
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alignment | left |
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\Omega_R = \Omega_e +\Omega_{sh} + \Omega_m |
The usual practice is to use relative volumes:
LaTeX Math Block |
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anchor | Omega_R |
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alignment | left |
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\phi_e = \frac{\Omega_e}{\Omega_R}, \quad V_{sh} = \frac{\Omega_{sh}}{\Omega_R}, \quad V_m = \frac{\Omega_m}{\Omega_R} |
which are measured in V/V units (or fracs) and honor the following constraint:
LaTeX Math Block |
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\phi_e +V_{sh} + V_m = 1 |
The relative effective pore volume
contains free or connate fluids (water, oil , gas) and called effective porosity.It corresponds to the air porosity of the dried laboratory cores:
LaTeX Math Inline |
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body | \phi_e = V_{\rm air \, core} |
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.