The subject matter of this specification can be embodied in, among other things, a system that includes a three-dimensional fabricator. An image processing module acquires an image of a rock sample having a network of pores, a transformation module transforms the image into a binary matrix and determine a set of statistical moments of the binary matrix, a layer generation module generates a first representation of a first stochastic layer based on the set and emulative of the rock sample and generates a second representation of a second stochastic layer based on the set and emulative of the rock sample. An arrangement module arranges the first representation and the second representation as adjacent layers of a three-dimensional model emulative of the rock sample, and provides the first representation and the second representation to the 3D fabricator for fabrication as a physical three-dimensional fluid micromodel emulative of the rock sample.