Elastic properties of rocks control the behavior of seismic waves such as wave amplitudes and speeds. Usually, elastic properties of rocks are measured in the laboratory. Unfortunately, some laboratory measurements are invasive. Digital Rock Physics (DRP) provides an alternative solution by simulating common measurements on computerized tomography images (CT-images) of the samples. However, evaluating the elastic properties of rocks using "segmentation-based DRP" is not accurate. Here, we propose an automatic inversion-based algorithm to estimate the elastic properties of monomineralic rocks. The method is based on the "segmentation-less DRP" where elastic moduli of rocks are estimated from CT-images without the need for initial segmentation of minerals or pore space. The proposed strategy iteratively evaluates the spatial distribution of pore spaces in the CT-images until the predicted porosity of the sample matches the porosity measured in the laboratory. The method is tested on a Berea sandstone plug. Numerical wave simulations are performed on the CT-images of the sample in order to estimate the elastic properties of the sample. Numerical results are compared with laboratory measurements. The proposed method, the inversion-assisted segmentation-less approach, shows a significant improvement over the traditional segmentation based DRP approach. The proposed method has a mismatch of +4.1% and +10% with respect to the measured P-wave and S-wave speeds. The segmentation approach overestimates P- and S-wave velocities by 38% and 28%, respectively. Future studies are still needed to improve the accuracy and extend the method to multimineralic rocks.
Presentation Date: Tuesday, September 17, 2019
Session Start Time: 1:50 PM
Presentation Start Time: 2:15 PM
Location: Poster Station 1
Presentation Type: Poster