Abstract: A computer-implemented system, method, and software are provided for solving linear systems of equations arising in reservoir simulation. A linear system of fluid flow equations, including a plurality of unknown variables, is provided that represents fluid flow properties in a geological formation of a subterranean reservoir. Block diagonal scaling is applied to the linear system of fluid flow equations. Threshold incomplete lower-upper approximate factorization is applied to obtain a preconditioning matrix, which can be used to iteratively solve unknown variables associated with the system of fluid flow equations. Preconditioning can be used directly as part of a preconditioned Krylov subspace method or alternatively as a 2nd stage preconditioner in a CPR algorithm.

Abstract: A computer-implemented system, method, and software are provided for solving linear systems of equations arising in reservoir simulation. A linear system of fluid flow equations, including a plurality of unknown variables, is provided that represents fluid flow properties in a geological formation of a subterranean reservoir. Block diagonal scaling is applied to the linear system of fluid flow equations. Threshold incomplete lower-upper approximate factorization is applied to obtain a preconditioning matrix, which can be used to iteratively solve unknown variables associated with the system of fluid flow equations. Preconditioning can be used directly as part of a preconditioned Krylov subspace method or alternatively as a 2nd stage preconditioner in a CPR algorithm.

Abstract: A Linear Solver method and apparatus, embodied in a Simulator and adapted for solving systems of non-linear partial differential equations and systems of linear equations representing physical characteristics of an oil and/or gas reservoir, includes receiving a first signal representing physical characteristics of a reservoir, obtaining a residual vector {right arrow over (r)}0 from the first signal (representing errors associated with a system of nonlinear equations describing the reservoir) and a first matrix A0(representing the sensitivity of the residual vector to changes in a system of nonlinear equations), recursively decomposing matrix A0 into a lower block triangular matrix, an upper block triangular matrix, and a diagonal matrix, and generating a second matrix M0 that is an approximation to matrix A0.