Implementation framework for numerical transport models: Application for underground hydrogen storage

This paper presents a methodology that enables research groups to develop their conceptual and numerical models in a mutually supportive way, with reduced computational effort and considerable implementation freedom. This approach is particularly intended for those working to improve the characterisation of underground hydrogen storage. The use of platforms such as Comsol Multiphysics is proposed, which, together with a widely validated numerical environment, offers multiphysics capabilities that allow the numerical model to be adapted to different conceptual approximations. In addition, its automatic symbolic differentiation functionality helps to generate clear, efficient and computationally powerful models. The methodology allows researchers to focus on conceptual development and minimises the burden of numerical implementation. To illustrate the application of the approach, highlighting the use of Comsol Multiphysics not only for its built-in simulation capabilities but also as an implementation environment, the development process of a new calculation code called X2H is described. Its qualification demonstrates that robust and accurate numerical tools can be obtained, with performance comparable to other the codes widely used in Reservoir Engineering.