The impact of heterogeneity on capillary trapping during geological carbon storage
File(s)
Author(s)
Harris, Catrin
Type
Thesis
Abstract
Capillary heterogeneity trapping has the potential to significantly improve the security of CO2 storage in underground aquifers. Small-scale heterogeneities could enhance the level of trapping in natural rocks and provide greater storage capacity. Capillary heterogeneities act to trap CO2 at saturations greater than expected from pore-scale residual trapping processes alone as a result of capillary pressure barriers. The aim of this work is to understand the effect of natural rock heterogeneities on capillary trapping over different length scales, during CO2 sequestration.
A multiscale approach is applied, combining experimental characterisation and numerical modelling, to create a physics-based representation of capillary heterogeneity trapping. The capillary heterogeneity trapped saturation during CO2 storage post-imbibition is quantified through a 1D analytical model. The analytical model predicts rate-dependency of capillary heterogeneity trapping, validated through experiments. Steady-state core flooding experiments with medical X-ray CT scanning provide a detailed characterisation of continuum multiphase flow properties, including residual trapping characteristics, over cm-scales. These experiments highlight the importance in correctly identifying the mechanism by which saturation is trapped at the core-scale and extracting appropriate trapping relationships when upscaling to the field. This motivated a study which focused on incorporating uncertainty in core and field-scale data into models of the Captain Sandstone, a UK target storage site.
To investigate the flow dynamics in heterogeneous sandstone cores, state of the art synchrotron-based X-ray micro-CT experiments at the Australian synchrotron (ANSTO) and European synchrotron (ESRF) have been carried out. These experiments investigated how larger scale capillary heterogeneity trapping processes are impacted by pore-scale filling events, across samples with different heterogeneity types. The resulting saturation distributions demonstrate the impact of cm-scale heterogeneity on pore-scale processes, which in turn influence large scale behaviour. These novel insights develop our understanding of the impact of heterogeneity on fluid migration and capillary trapping from the pore-to-core-to-field scale.
A multiscale approach is applied, combining experimental characterisation and numerical modelling, to create a physics-based representation of capillary heterogeneity trapping. The capillary heterogeneity trapped saturation during CO2 storage post-imbibition is quantified through a 1D analytical model. The analytical model predicts rate-dependency of capillary heterogeneity trapping, validated through experiments. Steady-state core flooding experiments with medical X-ray CT scanning provide a detailed characterisation of continuum multiphase flow properties, including residual trapping characteristics, over cm-scales. These experiments highlight the importance in correctly identifying the mechanism by which saturation is trapped at the core-scale and extracting appropriate trapping relationships when upscaling to the field. This motivated a study which focused on incorporating uncertainty in core and field-scale data into models of the Captain Sandstone, a UK target storage site.
To investigate the flow dynamics in heterogeneous sandstone cores, state of the art synchrotron-based X-ray micro-CT experiments at the Australian synchrotron (ANSTO) and European synchrotron (ESRF) have been carried out. These experiments investigated how larger scale capillary heterogeneity trapping processes are impacted by pore-scale filling events, across samples with different heterogeneity types. The resulting saturation distributions demonstrate the impact of cm-scale heterogeneity on pore-scale processes, which in turn influence large scale behaviour. These novel insights develop our understanding of the impact of heterogeneity on fluid migration and capillary trapping from the pore-to-core-to-field scale.
Version
Open Access
Date Issued
2024-04
Date Awarded
2024-07
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Muggeridge, Ann
Krevor, Samuel
Jackson, Samuel
Sponsor
Engineering and Physical Sciences Research Council
British Petroleum Company
Grant Number
EP/R513052/1
Publisher Department
Earth Science & Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)