A mixed pressure-velocity formulation to model flow in heterogeneous porous media with physics-informed neural networks

•Physics Informed Neural Networks (PINNs) is a promising technique.•Current implementation of PINNs face convergence issues in heterogeneous domains.•A new implementation is proposed based on the mixed formulation of the equations.•The new implementation simulate flow, regardless the level and type of heterogeneity.•It provide high accurate results without additional learning time.