Application of Geostatistical Inversion of geophysical data for RMR estimation

Geostatistical inverse approach using geophysical data was applied to indirectly make the RMR classification at points apart from boreholes. The geostatistical appoach was usually used to find optimized estimation which supports two or more different physical properties at unsampled points. However, in this study, an approach to solve inverse problem was proposed. The primary variable, RMR values obtained at known boreholes, is geostatistically simulated with many realizations at pre-defined grid point according to the variogram model. The simulated values are sequentially compared with the physical property result from geophysical survey, DC resistivity data, at an arbitrary grid point, and the most similar one is chosen. This process means that the spatial distribution of primary variable, RMR, is conformed well to the original pattern of the borehole observation, and ensure to fit the geophysical survey result to reflect the correlation between different physical properties. Some additional statistical analyses were performed to decide the reasonable simulation number and to see the variation of estimated RMR value around boreholes.