Amott test

The Amott test is one of the most widely used empirical wettability measurements for reservoir cores in petroleum engineering.

This test defines two different indices: the Amott water index (

It is a number between −1 and 1 describing wettability of a rock in drainage processes.

It is defined as: These two indices are obtained from special core analysis (SCAL) experiments (porous plate or centrifuge) by plotting the capillary pressure curve as a function of the water saturation as shown on figure 1: with

is the water saturation for a zero capillary pressure during the imbibition process,

is the oil saturation for a zero capillary pressure during the secondary drainage process,