Constraining Geostatistical Simulations of Delta Hydrofacies by Using Machine Correlation

In some hydrogeology applications, the only subsurface geological information available comes from a small number of boreholes from which hydrofacies have been intersected and identified. Geostatistical simulation is a widely used stochastic technique for generating a set of possible hydrofacies images that cover the range of the complexity and heterogeneity of the structures. However, the uncertainty due to the very sparse data may be significant to the extent that the simulated images cover an unrealistically large range of possibilities for the hydrofacies characteristics. In such cases it may be desirable to constrain the simulations so as to provide a more realistic, or plausible, set of simulations. In the absence of wireline logging, outcrops, geophysics, production data or any other types of hard data, we propose the use of machine numerical correlation between hydrofacies at the boreholes as a means of constraining the range of plausible simulations. The procedure is used to simulate delta hydrofacies in a coastal aquifer in Almeria (Southern Spain) where the variability of the hydrofacies is critical for managing problems related to seawater intrusion.