I was one of the co-investigators in The Center for Geological Storage of CO2, an Energy Frontier Research Center at the University of Illinois from 2014 to 2019. With prior expertise in pore-scale direct numerical simulation of single phase flow, and having studied the Digital Rocks Physics literature, I was confident that my research team could use micro-CT scans of rock samples from a field injection site along with lattice Boltzmann models of two-phase flow to readily compute core-scale relative permeability and capillary pressure relations. At the time, the University of Illinois was home to one of the most powerful supercomputers hosted at an academic institution. We had a talented group of graduate students and post-docs, plus another team doing cutting edge microfluidics experiments for validation. We had a real field site with active CO2 injection, monitoring and sampling. What could go wrong?

We learned that there were challenges at every step: technical limits and artifacts in the xray scans, the highly heterogeneous Mt. Simon sandstone, daunting computational requirements and numerical instabilities in conventional lattice Boltzmann models, unforeseen complications due to the small viscosity of supercritical CO2, and others. In this talk I will give an overview of these challenges, and discuss development, validation and applications of a lattice Boltzmann code. I will also report some results showing that core-scale relative permeability curves computed by computationally simple porenetwork models are often comparable to those computed by lattice Boltzmann models. While still a neophyte with only six years of experience in multiphase pore scale simulation, I will offer some perspectives on future opportunities.