Real Time Monitoring of Permeability, Elastic Moduli and Strength in Sands and Shales Using Digital Rock Physics

Abstract

Abstract The Digital Rock Physics (DRP) technology is based on a rigorous numerical simulation of physical experiments in a realistic pore space, at the pore-scale level. The output is usually a macroscopic property conventionally measured in the lab. For example, single-phase viscous fluid flow simulation through a digitized pore space provides absolute permeability. A simulation of electrical current provides conductivity, and a simulation of the stress field provides the elastic moduli and strength. DRP complements lab measurements and, at the same time, enormously enhances the geoscientist's capabilities because digital experiments can be conducted in real time and on small fragments of rock, such as drill cuttings. In this paper, results of a feasibility study on DRP technology is reported using for the first time the drill cutting samples in obtaining petrophysical properties including permeability and porosity of formations. This real-time technology may become very beneficial to the industry once it is established that the results are reliable. The 3D digital pore space needed for numerical simulation has been recreated from 2D images by means of statistical simulation. An example is also presented where the 3D digital pore space was obtained by direct CT scanning of drill cutting. The resulting macroscopic rock properties have been compared to independently obtained core data from laboratory measurements and log data from the same interval where cuttings are obtained.