This paper describes a parallel solver framework focused on flow and geomechanics reservoir simulation applications. It has been designed to run efficiently on a wide range of target platforms, from desktop workstations to heterogeneous clusters of multicore nodes, with or without GPUs, using a framework for distributed matrices and vectors based on a two-tier hierarchical architecture. Results show good parallel scalability on clusters of multicore nodes. Comparisons with the PETSc library indicate it is competitive with the best available tools. Preliminary tests indicate good speedups and parallel scalability also on multiple GPUs.