PorePy: an open-source software for simulation of multiphysics processes in fractured porous media

Development of models and dedicated numerical methods for dynamics in fractured rocks is an active research field, with research moving towards increasingly advanced process couplings and complex fracture networks. The inclusion of coupled processes in simulation models is challenged by the high aspect ratio of the fractures, the complex geometry of fracture networks, and the crucial impact of processes that completely change characteristics on the fracture-rock interface. This paper provides a general discussion of design principles for introducing fractures in simulators, and defines a framework for integrated modeling, discretization, and computer implementation. The framework is implemented in the open-source simulation software PorePy, which can serve as a flexible prototyping tool for multiphysics problems in fractured rocks. Based on a representation of the fractures and their intersections as lower-dimensional objects, we discuss data structures for mixed-dimensional grids, formulation of multiphysics problems, and discretizations that utilize existing software. We further present aPythonimplementation of these concepts in the PorePy open-source software tool, which is aimed at coupled simulation of flow and transport in three-dimensional fractured reservoirs as well as deformation of fractures and the reservoir in general. We present validation by benchmarks for flow, poroelasticity, and fracture deformation in porous media. The flexibility of the framework is then illustrated by simulations of non-linearly coupled flow and transport and of injection-driven deformation of fractures. All results can be reproduced by openly available simulation scripts.

Automated summary

Development of models and methods for dynamics in fractured rocks is an active research field, facing challenges such as high aspect ratio of fractures, complex fracture networks, and crucial impact of changing processes on fracture-rock interface. This paper discusses design principles and framework for introducing fractures in simulators, implemented in the open-source software PorePy for coupled simulation of flow, transport, and deformation in fractured reservoirs. The flexibility and validation of the framework are demonstrated through simulations of flow, poroelasticity, fracture deformation, and injection-driven fracture deformation. All results are reproducible using openly available simulation scripts.