changes.mady.by.user Arthur Aslanyan (Nafta College)
Saved on Nov 20, 2018
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\frac{1}{R_t} = \frac{\phi_e^m \, s_w^n }{A R_w} \quad \Rightarrow \quad s_w = \Big ( \frac{A}{\phi_e^m} \; \frac{R_w}{R_t} \Big) ^{1/n}
where
dimensionless constant, characterizing the rock matrix contribution to the total electrical resistivity
0.5 ÷ 1,
default value is 1 for sandstones and 0.9 for limestones
1.5 ÷ 2.5, default value is 2
Archie model is usually used in: