Theoretical correlations between the elastic and electrical properties in layered porous rocks with cracks of varying orientations

Abstract

Cracks that are widely existing in geological formations play an important role in affecting the elastic and electrical rock properties, which are remotely measured for detecting and characterizing cracked rocks. Joint interpretation of the complementary elastic and electrical data is expected to give a better assessment of the cracks. However, the correlations between the elastic and electrical rock properties, which are the key to the successful joint interpretation, remain poorly understood in layered porous rocks with cracks of varying orientations. We reviewed and summarized the most recent advances in the theoretical models for the elastic and electrical properties of layered porous rocks with inclined and rotated cracks as well as with randomly orienting cracks. The limitations of the models were identified by comparing the modeling results with available experimental data, and we applied the models within their validity range to obtaining theoretically the correlations between the elastic and electrical properties in layered porous rocks with cracks of the above-mentioned orientations, in the horizontal and vertical directions, respectively. We showed that the elastic and electrical properties are systematically correlated with cracks of varying crack densities and aspect ratios, different cracks orientations affect the correlations in varying ways. The results not only illustrate the link between the elastic and electrical properties in cracked rocks but also have important practical applications when the seismic and electromagnetic exploration data are jointly interpreted to gain better knowledge about the subsurface Earth, although future work is required to extend the models to more realistic cracked formations and to experimentally test the validity of the models and the theoretically obtained joint correlations.