A Parallel Solver for Large Scale DFN Flow Simulations

A parallel solver for large scale DFN flow simulations. Terms of use: This article is made available under terms and conditions applicable to Open Access Policy Article ("Public-All rights reserved") , as described at http://porto.polito.it/terms_and_conditions. html Porto, the institutional repository of the Politecnico di Torino, is provided by the University Library and the IT-Services. The aim is to enable open access to all the world. Please share with us how this access benefits you. Your story matters. Abstract. Flows in fractured media have been modeled with many different approaches in order to get reliable and efficient simulations for many critical applications. The common issues to be tackled are the wide range of scales involved in the phenomenon, the complexity of the domain and the huge computational cost. In the present paper we propose a parallel implementation of the PDE-constrained optimization method presented in [3, 4, 5] for dealing with arbitrary Discrete Fracture Networks on non conforming grids. We show the scalability performances and the efficiency of the parallel algorithm and we also test the robustness of the method on complex and strongly connected DFN configurations, that would result very difficult to mesh with conventional approaches relying on some kind of mesh conformity at the interfaces. 1. Introduction. The simulation of flows in fractured media is a challenging issue relevant in several critical applications: Oil&Gas enhanced production, nuclear waste geological storage, carbon dioxide geological storage, geothermal applications, energy and gas storage. The flow mainly takes place in the fractures and the contribution of the surrounding rock matrix can have, in many cases, a marginal impact on the flow pattern. Intensity and directionality of flow largely depend on the distribution of fractures and on their hydraulic properties. Several models have been proposed for the simulation of flows in fractured media. Here we consider the Discrete Fracture Network (DFN) model [8, 15, 7], with polygonal planar fractures representing the real fractures of the medium. Since the actual distribution of the fractures in a large scale geological basin can not be precisely determined in a deterministc way, DFNs are built as representations of natural media starting from stochastic distributions derived from " in situ " measurements [6, 8, 12, 15, 21, 41]. DFN flow simulations are also a starting point for investigating the hydraulic behaviour and hydraulic and mechanical interactions One of the major complexities related to standard discretizations is the construction of good …