Simulations of the effects of diagenesis on the evolution of sandstone porosity

Automated image analysis and image processing techniques make possible the simulation of sandstone diagenesis and prediction of pore system modification. Diagenetic processes in real rocks are simulated using a combination of element X-ray maps and backscattered electron images. Processes can also be simulated for computer-generated sand packs by image analysis and image processing. Compaction is simulated by moving grain centers closer together; overgrowth-type cementation is simulated by dilation of free grain surfaces; mineral dissolution is simulated by selective removal of specific minerals identified by the combination of element X-ray maps and backscattered electron images. The original and modified images can be processed and analyzed to reveal all the parameters needed to predict permeability using a Kozeny-Carman type equation. The computer modeling and image analysis approach can also be used to determine the specific effects of various diagenetic processes on porosity. The results are encouragingly realistic by reference to the few available well-characterized empirical datasets.