Development of experimental methods for intermediate scale testing of deep geologic CO2 sequestration trapping processes at ambient laboratory conditions

Abstract

Carbon Capture and Storage (CCS) is a potential strategy to reduce CO2 emissions into the atmosphere. Deep geological formations provide a viable storage site for significant amounts of CO2, however their depth from the surface and extreme conditions make planning and monitoring a CCS project difficult. Improved knowledge of the fundamental processes involved in trapping of CO2 in naturally heterogeneous deep saline aquifers in an efficient and safe manner is beneficial for present and future projects. Understanding and study of these processes under controlled conditions in field settings is not feasible. As an alternative, this study developed and experimental methods to study capillary and dissolution trapping processes at ambient laboratory conditions using analog fluids in place of supercritical CO2 (scCO2) and brine. These experimental methods allow measuring and analyzing the effects of heterogeneity on carbon sequestration at larger laboratory scales than previously done. The results of these types of experiments help researchers develop improved models and test them for better project design and performance assessment in the field for storage permanence. These experiments include tests that obtain the constitutive relationships of capillary pressure and relative permeability, injection of scCO2 into a 2D-confined aquifer that uses an x-ray attenuation technique to precisely track the plume and measure trapping saturations, and an intermediate scale experiment of dissolution fingering that will form the base for future experiments seeking to understand dissolution trapping in formations with low permeability zones. Strategies to accurately model the intermediate scale capillary trapping experiment using T2VOC were also developed.