System and Method for Flexible and Efficient Simulation of Varying Fracture Density in a Reservoir Simulator

摘要

Simulation system and method for a reservoir represented by a model having a plurality of matrix nodes, a plurality of fracture nodes, a fracture zone and a fracture-free zone are described. One embodiment includes computer-implemented steps of, for each of a plurality of matrix nodes in interconnected zones, characterizing the matrix nodes as dual matrix nodes or non-dual matrix nodes. Dual matrix nodes may be treated as a block and eliminated, after which the coefficient matrix and RHS vector for the model are updated. In-fill patterns between and among fracture nodes and non-dual matrix nodes resulting from the elimination are determined. For non-dual matrix nodes, the nodes are merged to a fracture grid, after which the coefficient matrix and RHS vector for the model are updated accordingly. The resultant linear system is linearly solved, and backsolving is performed for any eliminated dual matrix nodes.

主权项

1. A method for performing simulation of a reservoir represented by a model having a plurality of matrix nodes, a plurality of fracture nodes, at least one fracture zone and at least one fracture-free zone, the method comprising computer-implemented steps of:
for each of a plurality of matrix nodes comprising interconnected zones, characterizing the matrix nodes; for a block comprised of one or more dual matrix nodes, eliminating the block and updating a coefficient matrix and RHS vector for the model accordingly; determining in-fill patterns between fracture nodes, including virtual fracture nodes, that will result from the elimination; for one or more virtual fracture nodes, merging the virtual fracture nodes to a fracture grid and updating the coefficient matrix and RHS vector for the model accordingly; solving the resultant linear system using a linear solver; and backsolving for the eliminated dual matrix nodes.