Hydraulic Characterization of Fractured Porous Media: A CT-Driven Approach with Naiver-Stokes-Based Modelling

Characterization of hydraulic property is essential for reliable and efficient groundwater modelling. Rock properties like permeability and hydraulic conductivity are regarded as key parameters that play an important role in simulating fluid flow behaviour through a porous media. In particular, hydraulic conductivity is the most important parameter in the sub-surface flow and transport. Fractured porous media pose a great challenge for characterization due to the unknown nature of fracturs, their density and distribution.

This study explores a workflow of two different methods to accurately estimate the permeability and the corresponding hydraulic conductivity of a fractured basalt from the Harrat Rahat area in Saudi Arabia. These workflow combines computer tomography (CT) scan and numerical modelling to find reliable characterization of fractured rocks. First, the rock was characterized using computer tomography (CT) and both porosity and permeability are calculated using Lattice-Boltzmann approach in Avizo 3D software. Following which a model was built in COMSOL Multiphysics using the 3D image obtained from the CT scan, and Naiver-Stokes (NS) equation was used to simulate the flow in the model.

As a result, the average Darcian velocity was calculated from which the hydraulic conductivity was obtained. Finally, the results from the model were compared with those obtained from the CT scan, which shows a good agreement between both approaches.

Therefore, comparative analysis of the two approaches validated the effectiveness of combining imaging techniques like CT scanning and numerical modelling for characterizing hydraulic properties in fractured porous media.