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Si us plau utilitzeu sempre aquest identificador per citar o enllaçar aquest document: https://hdl.handle.net/2445/183624
Carbon capture and storage in compressional basins: global to reservoir-scale assessments and integrated case study of the Puig-reig anticline (SE Pyrenees)
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[eng] Carbon capture and storage (CCS) has been proposed as a potential technology to mitigate climate change. However, there is currently a huge gap between the global CCS deployment and that which will be ultimately required. To date, CCS deployment has been restricted to the most favourable tectonic settings, such as extensional passive margin and post-rift basins and compressional foreland basins. In addition, CCS deployment has stalled in most countries, with only limited commercial projects realised mainly in hydrocarbon-rich countries for enhanced oil recovery. This Ph.D. thesis aims to assess the potential of CCS development in compressional basins and hydrocarbon-limited regions at different scales: from a global-scale assessment to a national-scale assessment in Spain and finally, to a reservoir-scale analogue case study, focusing on the Puig-reig anticline (SE Pyrenees).
Compressional settings host some of the most significant oil and gas resources in the world and will be key to the large-scale deployment of CCS. On the global scale, we present an integrated source-to-sink analysis tool that combines basin distribution, hydrocarbon resources and CO2 emissions to assess the potential of compressional basins for CCS development. This methodology allows identifying five high-priority regions for prospective CCS development in compressional basins: North America, north-western South America, south-eastern Europe, the western Middle East and western China. The results indicate that compressional basins will have to play a critical role in the future of CCS if this technology is to be implemented worldwide.
Instead of developing CCS via CO2 enhanced oil recovery (CO2-EOR), hydrocarbon-limited countries need to devise alternative strategies if they intend to implement CCS in their decarbonisation strategies. On the national scale, we present a novel systematic source-to-sink assessment methodology based on a hubs and clusters approach to identify favourable regions for CCS deployment in hydrocarbon-limited countries. Throughout the evaluation of the Spanish case study, we identify 15 emission hubs from the power and the hard-to-abate sectors and priority source- to-sink clusters, based on screening and ranking processes using a multi-criteria decision-making method. North-Western and North-Eastern Spain are recognised as priority regions due to resilience provided by different types of CO2 sources and multiple geological storage structures. CCS, especially in the hard-to-abate sector, and in combination with other low-carbon energies, remains a significant contributor to the Paris Agreement’s mid-century net-zero target. This methodology can attract renewed public and political interest in viable deployment pathways of CCS in hydrocarbon-limited
countries.
The Ebro Foreland Basin, identified as one of the most potential areas for CCS development in Spain, is a typical hydrocarbon-limited compressional basin with low availability of geological and geophysical data required for the suitability assessment for CO2 storage. In this work, we carry out an integrated study of the Puig-reig anticline (SE Pyrenees) to be used as an outcrop analogue to explore the reservoir potential of foreland basin margin sedimentary systems. This anticline exposes continuous outcrops deposited in a proximal to medial fluvial fan system with an overall southeast downstream trend. The proximal deposits, mainly spreading in the northwest portion of the anticline, are characterised by conglomerates with minor interbedded sandstones. These are interpreted as having been deposited from unconfined flash floods and wide-shallow channel streams. The medial deposits, covering the rest of the anticline, consist of interbedded beds of conglomerates, sandstones and claystones, deposited in braided channel streams and overbanks.
In order to understand the fracture distribution in the Puig-reig anticline and how it can potentially affect reservoir potential, fracture networks have been characterised using the linear scanline method, and four fracture sets (F1 to F4) have been identified in the target structure. The north limb shows low fracture intensity but large fracture length and aperture. The crest and the crest-limb transition zones present relatively high fracture intensity and variable fracture length and aperture. The south limb has low fracture intensity and small fracture length and aperture. Based on multiple linear regression analysis, we observe that fracture intensity is mainly controlled by the structural position, bedding thickness and lithological associations, with more intense fracturing in thin sandstone layers with multiple interlayers of fine deposits in the high strain zones. The fracture length mainly depends on bedding thickness and is affected by lithological associations. The fracture apertures are mainly controlled by lithofacies.
An integrated analysis of structural, petrological and geochemical characteristics allows identifying five generations of calcite cements (Cc0 to Cc4) and fluid regimes in the Puig-reig anticline. Before intensive deformation, Cc0 precipitated in intergranular porosity from meteoric fluids in the phreatic zone. During the most intense phase of thrusting and folding, Cc1 precipitated in intergranular porosity, faults and F1 to F4 fracture sets from hydrothermal fluids migrated from the deep areas of the SE Pyrenees. During the late stage of fold growth, Cc2 mainly precipitated in normal and strike- slip faults in the anticline crest from the mixing between hydrothermal and meteoric fluids during the crestal collapse, or from hydrothermal fluids with shallower burial depth compared to that of Cc1.
Cc3 mainly precipitated in faults and F1 and F4 fracture sets in the north-western zone of the anticline from formation fluids probably migrated through the frontal thrusts. During the continuous denudation, Cc4 precipitated in the reopened F1 to F4 fracture sets from meteoric fluids.
The comparison of the Puig-reig anticline with other similar depositional and tectonic settings worldwide allows exploring the reservoir potential for CO2 storage at foreland basin margins. In the Puig-reig anticline, the proximal to medial deposits present low porosity of host rocks due to the prevailing presence of calcite cement, with limited high porosity concentrated in massive medium and coarse lithofacies in the medial fluvial fan. Sandstone lithofacies deposited from the medial fluvial fan and located in the high strain zones feature relatively high fracture intensity, which have relative high potential to be effective reservoirs. The study conducted in the Puig-reig anticline provides a conceptual model useful to understand the reservoir characteristics at the basin margins. According to this model, the reservoir potential is comprehensively controlled by sedimentology, diagenesis and deformation. The effective combination of both structure and facies can make basin margin locations potential areas for effective reservoirs, even in the presence of overall low porosity. Future work will focus on building a static reservoir model of the Puig-reig anticline based on the results obtained in the sedimentology, fracture and diagenesis studies, and finally carrying out fluid flow simulations to determine the main controls on CO2 injection and storage in such a geological setting.
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SUN, Xiaolong. Carbon capture and storage in compressional basins: global to reservoir-scale assessments and integrated case study of the Puig-reig anticline (SE Pyrenees). [consulta: 10 de desembre de 2025]. [Disponible a: https://hdl.handle.net/2445/183624]