ZERT Task 4: Fundamental geochemical and hydrological investigations of long-term CO2 storage
ZERT Task 4 Goal
To develop understanding and confidence in solubility trapping, residual gas trapping and mineral trapping, and to identify new trapping mechanisms that can contribute to even greater storage security.
ZERT Task 4 Overview
Theory and experiments will be used to develop a greater understanding of solubility trapping, residual gas trapping and mineral trapping and to identify new trapping mechanisms that can provide even greater storage security.
Experiments to improve our understanding of residual gas trapping will be conducted in a high pressure 1-D column with X-Ray CT scanning capability. These experiments are designed to allow monitoring the evolution of trapped gas over time and as fluid slowly dissolves the trapped gas. Theoretical studies and numerical simulation will be used to interpret and generalize the results from these experiments. Planning to include measurements to correlate gas-water saturation with geophysical properties (e.g., acoustic wave speed, electrical conductivity) will be undertaken for future investigation in this task.
A cross-section of Frio sandstone partially saturated with water (52%) and CO2 (48%). The black fillings show CO2 and the blue color marks water. Image size is presented by the number of voxels
CO2 distribution in the pore space at 34% (left) and 75% (right) gas saturation.
Capillary pressure curves for Frio sandstone. Red curves are computed capillary pressures for different parts of the whole image. The blue curve is mercury injection data. The collapse of red curves indicates that the sample size selected for analysis is representative enough. Computed underestimate water saturation at high capillary pressures due to the presence of microporosity (left). The data fitting problem is fixed by introducing a microporosity correction factor (right).