Local Embedded Discrete Fracture Model (LEDFM)

TL;DR

This paper introduces LEDFM, an improved fracture modeling approach that enhances EDFM by relaxing pressure assumptions and accounting for impermeable fractures, leading to more accurate flow simulations in fractured porous media.

Contribution

The paper proposes LEDFM, a novel extension of EDFM, incorporating local problem solutions to better model fracture-medium interactions and overcome previous limitations.

Findings

LEDFM improves fracture-medium coupling accuracy.

Numerical tests confirm better handling of impermeable fractures.

Enhanced modeling of flow in complex fractured systems.

Abstract

The study of flow in fractured porous media is a key ingredient for many geoscience applications, such as reservoir management and geothermal energy production. Modelling and simulation of these highly heterogeneous and geometrically complex systems require the adoption of non-standard numerical schemes. The Embedded Discrete Fracture Model (EDFM) is a simple and effective way to account for fractures with coarse and regular grids, but it suffers from some limitations: it assumes a linear pressure distribution around fractures, which holds true only far from the tips and fracture intersections, and it can be employed for highly permeable fractures only. In this paper we propose an improvement of EDFM which aims at overcoming these limitations computing an improved coupling between fractures and the surrounding porous medium by a) relaxing the linear pressure distribution assumption, b) accounting for impermeable fractures modifying near-fracture transmissibilities. These results are achieved by solving different types of local problems with a fine conforming grid, and computing new transmissibilities (for connections between fractures and the surrounding porous medium and those through the porous medium itself near to the fractures). Such local problems are inspired from numerical upscaling techniques present in the literature. The new method is called Local Embedded Discrete Fracture Model (LEDFM) and the results obtained from several numerical tests confirm the aforementioned improvements.