Abstract
We discuss the multi-block algorithm for an implicit black-oil model as implemented in a multi-phase simulator framework IPARS. The multi-block algorithm consists of decomposition of the simulation domain into multiple non-overlapping subdomains or blocks according to the geometric, geological and physical/chemical properties, distribution of wells, etc. Each block can have its own grid system, and the grids of the neighboring blocks can be non-matching on the interface, which allows, for example, for local grid refinement, or discrete fault or fracture modeling. Adjacent blocks are coupled across the interface by a set of conditions imposing continuity of the primary variables and component mass fluxes, which is realized with the use of special interface mortar variables. The resulting system is solved by an interface Newton procedure. Regularization techniques and preconditioners are proposed to improve the performance of the solver. The multi-block technique is effective and scalable, as shown by our numerical experiments. In addition, we present how the multi-block black-oil model has been used in the coupling of different physical models.
