Digital rock physics (DRP) aims at estimating rock physical properties from computed-tomography (CT) imagery. DRP could improve our knowledge of subsurface properties without increasing laboratory testing that is time consuming, expensive and might damage the rock samples. Classic DRP employs segmentation that assigns physical properties to CT imagery voxels. However, segmentation obliterates information leading to a loss of precision in the final result. Segmentation quality improves by scanning the sample at sub-micrometric resolution, but this leads to a trade-off: the scanning volume becomes millimetric and often non-representative for the studied lithology. To improve DRP accuracy, segmentation-less approaches have been proposed. Segmentation-less DRP methods can provide ultrasonic rock wave speeds that compare well to laboratory ultrasonic measurements. The present work extends the segmentation-less method to the static load test on a digitized Berea sandstone sample. To make the calculation possible - i.e., to handle large heterogeneous matrices, the National-Institute-of-Science-and-Technology (NIST) elas3d code has been translated to MATLAB language. Effective elastic properties, calculated through segmentation-less DRP, are similar to quasi-static laboratory measurements but lower than ultrasonic laboratory measurements. Such discrepancy could be related to scattering effects. Such results suggest that the segmentation-less method could represent a valid method to predict elastic properties of rocks through digital rock physics.
Presentation Date: Monday, September 25, 2017
Start Time: 1:50 PM
Location: Exhibit Hall C/D
Presentation Type: POSTER