Coupled discrete fracture and 3D continuum domain representation to efficiently capture gas transport from underground cavities
Date:
Washington D.C.
Poster at AGU 2018 Fall Meeting
Session: H51P Coupled Processes in Fractured Media Across Scales: Experimental and Modeling Advances
Abstract:
Driven primarily by barometric pumping, the time scale of relevant gas transport in fractured geologic media can vary from years to the order of days depending on the strength of the barometric signal and a variety of hydrogeologic parameters, including: rock type, fracture aperture, matrix permeability, porosity, and saturation. Although discrete fracture networks (DFNs) improve representations of preferential flow along fractures, they have limitations in transport applications where molecular and pressure diffusion into the rock matrix cannot be ignored. We will present numerical simulations that combine a single discrete fracture with an explicitly meshed 3D cavity zone. We employ a dual-porosity formulation to represent the matrix attached to the fracture in order to accurately model barometric pumping. Such simulations highlight the relative importance of different macro- and micro-scale processes in fractured flow and transport models while also promising to reduce computation time of multiphase simulations.