Near Wellbore Processes during Carbon Capture, Utilization, and Storage (CCUS): An Integrated Modeling Approach

Abstract

Carbon capture and storage (CCS) is a relatively new technology that captures CO2 before it reaches the atmosphere and safely stores it underground. CO2 storage will achieve significant climate change mitigation, only if it is implemented on a very large scale with considerable injection rates. To achieve a high injection rate, we need to ensure that the near wellbore area is clean because all the injected CO2 needs to pass through this zone before entering the reservoir. Clogging these paths reduces injectivity (ease of injection) and requires costly mitigation measures. In this PhD project, numerical models are developed at different scales to improve our understanding of near-well processes during CO2 storage and their effects on injectivity. It addresses the following research topics: 1. Thermodynamic modeling of complex systems: results showed that mutual solubilities of CO2 and H2O can provide a primary assessment of the possible risk of salt precipitation. 2. Continuum scale modeling of CO2 storage: results showed that the selected porosity-permeability relation is a significant source of uncertainty for simulation of injectivity impairment during CO2 injection. 3. Pore-scale modeling of mineral nucleation and growth: results showed that mineral nucleation should be modelled using a probabilistic approach to better predict the hydrodynamic properties of porous media. 4. Pore-scale modeling of salt aggregates formation during carbon storage: results showed that widely used porosity-permeability relations were unable to cover the clogging behavior of salt aggregates, indicating the need for developing a proper clogging model in this context.