Browsing by Author "Aminu, Mohammed Dahiru"

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    Carbon dioxide storage in the UK southern north sea: experimental and numerical analysis
    (2018-10) Aminu, Mohammed Dahiru; Manovic, Vasilije; Kolios, Athanasios
    This thesis contributes to the significant portfolio of research on carbon capture and storage (CCS) in general, and the potential for CO₂ storage with impurities within the UK Southern North Sea (UKSNS) to meet the global greenhouse gas emission reduction targets. First, this thesis extensively reviews the current developments in carbon dioxide storage, highlighting major options for CO₂ sequestration, storage site evaluation criteria, behaviour of CO₂ in the reservoir, methodologies for estimating storage capacity, appraisal of the major storage projects, and a projection of the future outlook for CO₂ storage. The review draws attention to the fact that although a high-quality knowledge base has been developed through CCS research, the main hinderance to CO₂ storage deployment is associated with public acceptability of the technology. Second, this thesis involves laboratory experimental investigation of the effect of impure CO₂ on reservoir grain size distributions and permeability using rock samples from the Bunter saline aquifer. The thesis shows that the presence of impurities in the CO₂ stream can affect the grain size distribution and fluid transmissivity. Third, this thesis uses numerical modelling to evaluate the effect of impure CO₂ on reservoir performance with a case study from the Bunter saline aquifer. The results show that depending on the impurities present in the CO₂ stream, the limits of stability during storage operations in saline aquifer varies, however, the variation does not affect reservoir performance negatively during long-term injection and storage.
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    CO2-brine-rock interactions: The effect of impurities on grain size distribution and reservoir permeability
    (Elsevier, 2018-08-25) Aminu, Mohammed Dahiru; Nabavi, Seyed Ali; Manovic, Vasilije
    The Bunter Sandstone formation in the UK’s southern North Sea has been identified as having the potential to store large volumes of CO2. Prior to injection, CO2 is captured with certain amounts of impurities, usually less than 5%vol. The dissolution of these impurities in formation water can cause chemical reactions between CO2, brine, and rock, which can affect the reservoir quality by altering properties such as permeability. In this study, we explored the effect of CO2 and impurities (NO2, SO2, H2S) on reservoir permeability by measuring changes in grain size distributions after a prolonged period of 9 months, simulating in situ experimental conditions. It was found that the effects of pure CO2 and CO2-H2S are relatively small, i.e., CO2 increased permeability by 5.5% and CO2-H2S decreased it by 5.5%. Also, CO2-SO2 slightly decreased permeability by 6.25%, while CO2-NO2 showed the most pronounced effect, reducing permeability by 41.6%. The decrease in permeability showed a correlation with decreasing pH of the formation water and this equally correlates with a decrease in geometric mean of the grain diameter. The findings from this study are aimed to be used in future modelling studies on reservoir performance during injection and storage, which also should account for the shifts in boundaries in the CO2 phase diagram, altering the reservoir properties and affecting the cost of storage.
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    A modelling study to evaluate the effect of impure CO2 on reservoir performance in a sandstone saline aquifer
    (Elsevier, 2020-08-03) Aminu, Mohammed Dahiru; Manovic, Vasilije
    Carbon capture and storage (CCS) is expected to play a key role in meeting greenhouse gas emissions reduction targets. In the UK Southern North Sea, the Bunter Sandstone formation (BSF) has been identified as a potential reservoir which can store very large amounts of CO2. The formation has fairly good porosity and permeability and is sealed with both effective caprock and base rock, making CO2 storage feasible at industrial scale. However, when CO2 is captured, it typically contains impurities, which may shift the boundaries of the CO2 phase diagram, implying that higher costs will be needed for storage operations. In this study, we modelled the effect of CO2 and impurities (NO2, SO2, H2S) on the reservoir performance of the BSF. The injection of CO2 at constant rate and pressure using a single horizontal well injection strategy was simulated for up to 30 years, as well as an additional 30 years of monitoring. The results suggest that impurities in the CO2 stream affect injectivity differently, but the effects are usually encountered during early stages of injection into the BSF and may not necessarily affect cumulative injection over an extended period. It was also found that porosity of the storage site is the most important factor controlling the limits on injection. The simulations also suggest that CO2 remains secured within the reservoir for 30 years after injection is completed, indicating that no post-injection leakage is anticipated.
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    A review of developments in carbon dioxide storage
    (Elsevier, 2017-09-21) Aminu, Mohammed Dahiru; Nabavi, Seyed Ali; Rochelle, Christopher A.; Manovic, Vasilije
    Carbon capture and storage (CCS) has been identified as an urgent, strategic and essential approach to reduce anthropogenic CO2 emissions, and mitigate the severe consequences of climate change. CO2 storage is the last step in the CCS chain and can be implemented mainly through oceanic and underground geological sequestration, and mineral carbonation. This review paper aims to provide state-of-the-art developments in CO2 storage. The review initially discussed the potential options for CO2 storage by highlighting the present status, current challenges and uncertainties associated with further deployment of established approaches (such as storage in saline aquifers and depleted oil and gas reservoirs) and feasibility demonstration of relatively newer storage concepts (such as hydrate storage and CO2-based enhanced geothermal systems). The second part of the review outlined the critical criteria that are necessary for storage site selection, including geological, geothermal, geohazards, hydrodynamic, basin maturity, and economic, societal and environmental factors. In the third section, the focus was on identification of CO2 behaviour within the reservoir during and after injection, namely injection-induced seismicity, potential leakage pathways, and long-term containment complexities associated with CO2-brine-rock interaction. In addition, a detailed review on storage capacity estimation methods based on different geological media and trapping mechanisms was provided. Finally, an overview of major CO2 storage projects, including their overall outcomes, were outlined. This review indicates that although CO2 storage is a technically proven strategy, the discussed challenges need to be addressed in order to accelerate the deployment of the technology. In addition, beside the necessity of techno-economic aspects, public acceptance of CO2 storage plays a central role in technology deployment, and the current ethical mechanisms need to be further improved.
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    Workflow for building and calibrating 3D pre-injection and 4D geomechanics modelling to assess caprock and fault integrity for geologic CO2 storage
    (Slovnaft VÚRUP, 2017-12-31) Aminu, Mohammed Dahiru; Ardo, Buhari U.; Jato, Musa A.
    Carbon capture and storage (CCS) has been established as a viable technology for the mitigation of climate change caused mainly by anthropogenic greenhouse gas emissions into the atmosphere. Ever since the publication of the special report on CCS by the Intergovernmental Panel on Climate Change in 2005, there has been an increased research and development in all areas of CCS. Some of these research involves use of numerical methods and models for optimizing storage and ensuring effective long term containment. In this paper, we propose a workflow for building and calibrating 3D preinjection and 4D geomechanics modelling to assess caprock and fault integrity for geologic carbon dioxide storage. The workflow presented here describes a seamless end -to-end process which combines a transparent flow of data with an easy-to-use graphical user interface. The workflow can conduct 3D static and 4D flow-, pressure-, and temperature-coupled calculations for rock deformations, failure and stresses. In highly heterogeneous and complex models, the workflow is capable of modelling multiple hundred faults, and multiple thousand discrete fractures. It allows the geological model, despite its high degree of complexity to be maintained throughout the geomechanical analyses process.