Residual trapping of carbon dioxide during geological storage—Insight gained through a pore-network modeling approach. (July 2018)

• Record Type: Journal Article
• Authors: Rasmusson, K.; Rasmusson, M.; Tsang, Y.; Benson, S.; Hingerl, F.; Fagerlund, F.; Niemi, A.
• Is Part Of: International journal of greenhouse gas control. Volume 74(2018)
• Page Start: 62
• Page End: 78
• Publication Date: 2018-07
• Subjects: CCS -- Heletz -- Pore-scale -- Pore-network model -- Quasi-static -- Capillary trapping; Greenhouse gases -- Environmental aspects -- Periodicals; Air -- Purification -- Technological innovations -- Periodicals; Gaz à effet de serre -- Périodiques; Gaz à effet de serre -- Réduction -- Périodiques; Air -- Purification -- Technological innovations; Greenhouse gases -- Environmental aspects; Periodicals; 363.73874605
• DOI: 10.1016/j.ijggc.2018.04.021
• Languages: English
• ISSNs: 1750-5836

Abstract

Highlights: A pore-network model was presented and used to study residual CO2 trapping. The PNM was calibrated using core sample data from Heletz sandstone. Drainage-imbibition scenarios were simulated to estimate trapping curves. The simulated trapping curves complemented experimental data. Occurrences of pore-scale events and the cluster size distribution were studied. Abstract: To reduce emissions of the greenhouse gas CO2 to the atmosphere, sequestration in deep saline aquifers is a viable strategy. Residual trapping is a key containment process important to the success of CO2 storage operations. While residual trapping affects CO2 migration over large scales, it is inherently a pore-scale process. Pore-network models (PNMs), capturing such processes, are useful for our understanding of residual trapping, and for upscaling trapping parameters for larger scale models. A PNM for simulation of quasi-static two-phase flow; CO2 intrusion (drainage) followed by water flooding (imbibition) was developed. It accounts for pore-scale displacement mechanisms, and was used to investigate residual CO2 trapping. The sensitivity of the residual CO2 saturation to several parameters was studied, to validate a trapping behavior in agreement with earlier studies. Then the PNM was calibrated to core sample data and used to simulate drainage-imbibition scenarios with different turning point saturations. From these the initial-residual saturation curves of CO2 in Heletz sandstone were estimated, essential for future macroscopic-scale simulations. Further, the occurrence of different pore-scale mechanisms were quantified and the size distribution of the residual clusters was shown to exhibit a bimodal appearance. The findings improve the understanding of residual trapping in Heletz sandstone.