We simulate magnetization decay in porous media using a random walk method.Simple sand pack systems were initially studied before actual porous and heterogeneous carbonates were investigated.Topologically equivalent sand pack networks were extracted from micro-CT images using a maximal ball algorithm.The simulated magnetization decay and T2 distribution in the images and networks were successfully compared with experimental data.The algorithm used in the simulations of NMR response in networks was validated using a tuned Berea network that reproduced experimental capillary pressure data in Bentheimer sandstone.The simulated magnetization decay and T2 distribution of this tuned network is shown to be in good agreement with experimental measurements. Significant differences were observed between the simulated magnetization decays of the micro-CT image and extracted network of carbonates.The coincidence between simulated and experimental magnetization decays and T2 distributions improved when networks are generated from capillary pressure data.
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