A supercoarsening multigrid method for poroelasticity in 3D coupled flow and geomechanics modeling

摘要: The Galerkin finite-element discretization of the force balance equation typically leads to large linear systems for geomechanical problems with realistic dimensions. In iteratively coupled flow and geomechanics modeling, a system is solved at every timestep often multiple times during coupling iterations. iterative solution stemming from poroelasticity equations constitutes most time-consuming memory-intensive component modeling. Block Jacobi, LSOR, Incomplete LU factorization are popular preconditioning techniques used accelerating systems. However, need more effective, efficient, robust still remains especially modeling requiring number timesteps. We developed supercoarsening multigrid method (SCMG) which can be multiplicatively combined commonly techniques. SCMG has been tested on variety involving single-phase depletion multiphase displacement in-situ hydrocarbons, CO2 injection, extreme material property contrasts. Our analysis indicates that consistently improves convergence properties arising equations, thus, accelerates simulations all cases subject investigation. joint utilization two-level ILU1 preconditioner emerges as optimal preconditioning/iterative strategy in great majority evaluated this work. BiCGSTAB solver converges rapidly compared PCG test cases, various SCMG-accelerated strategies applied both iterators.