1. A method for modelling a saturation dependant property in a sample comprising the steps of: (a) obtaining a spatially resolved measurement of fluid saturation in the sample using an external force; (b) determining a measured value of a saturation dependant property from the measurement; (c) fitting a model to the measured value to obtain a model value for the measured value; (d) optimising the fit of the model to the measured value by minimizing an error between the model and the measured value where the error is a distance between the measured value and the model value.