A Hybrid Digital–Experimental Workflow to Predict Two-Phase Relative Permeability in Tarmat-Bearing Reservoirs with Limited SCAL Data

This study presents a hybrid digital–experimental workflow for estimating two-phase relative permeability in tarmat-bearing reservoirs, particularly where Special Core Analysis (SCAL) data is unreliable. The methodology integrates routine core analysis (RCA) with image-based digital rock modelling to reconstruct realistic 3D pore-scale structures using a morphological approach that combines SEM-EDX and Micro-CT data. These synthetic models are embedded within a Digital Rock Physics (DRP) framework and used to simulate multiphase flow across clean, low-tarmat, and high-tarmat zones. Pore-scale simulations employing a pore network modelling (PNM) method were benchmarked against experimental SCAL data, showing strong agreement in the clean zone and consistent flow behaviour across tarmat variations. The computed relative permeability curves offer a flexible and scalable alternative for SCAL-derived inputs in dynamic reservoir simulation. The workflow is particularly suited for evaluating CO2 and hydrogen storage feasibility, where flow characterisation is critical but laboratory measurements are constrained. A workflow application to the Bunter Sandstone Formation is is planned as part of future research, supporting UK low-carbon energy projects by enhancing subsurface flow prediction under uncertain geological conditions.