Fast direct flow simulation in porous media by coupling with pore network and Laplace models.

• Up to 150 × speedup to steady state LBM by preconditioning with PNM and Laplace Solvers. • Velocity field and permeability error of PNM/Laplace Solvers corrected within 2,000 LBM timesteps. • Most effective on tight porous media; useful for reactive transport, fines migration, etc. Permeability characterises flow in porous rocks/media for upscaling, while steady-state flow fields allow analysis of reactive transport, fines migration, and tight unconventional rocks. Fast calculation of permeability and flow fields obtained from Pore Network Models (PNM) and Laplace Semi-Analytical Solvers (SAS) deviate from computationally demanding simulation of Navier Stokes Equations (NSE) due to flow and geometry simplifications. Coupling PNM/SAS with direct simulation via Lattice Boltzmann Method (LBM) provides 5-- 150 × speed-up without accuracy loss over 100 samples from 0.7mD to 3.5D. Permeability errors in PNM/SAS show 10-20% (up to 50-70%) error. PNM shows higher variance from geometric simplifications compared to SAS which only makes flow-based assumptions. PNM/SAS errors are eliminated by coupling with LBM at a fraction of LBM-only compute cost. Steady-state conditions with PNM/SAS-LBM are reached in < 2 , 000 timesteps, compared to LBM-only which can require > 10 5 timesteps in tight domains such as cemented sandstone, carbonate, coal, and shale. [ABSTRACT FROM AUTHOR]