1.
n. [Formation Evaluation]
A particular relation proposed by G.E. Archie between the
formation factor (F) and porosity (
phi), in which F = 1 /
phi^{m}, where the
porosity exponent, m, is a constant for a particular formation or type of rock. In the original work, Archie proposed that
m lay between 1.8 and 2.0 for
consolidated sandstones, and close to 1.3 for loosely consolidated sandstones.
m was named the
cementation exponent shortly afterwards. This relation is also known as the Archie II equation.