Abstract Core analysts principally study the storage, flow and saturation properties of porous rocks and sediments. Some of the derived parameters are specific to hydrocarbon production but many have commonality with other subsurface disciplines such as hydrology and soil science. Traditional core analysis involves direct physical experimentation on core plugs to derive a range of parameters used as calibration for conventional well logs, and to predict hydrocarbon reserves and recovery. The mechanisms and processes for obtaining such data have evolved significantly during the last century, from the manual instruments of the mid-twentieth century to the accredited digital data collection and recording of the 1990s onwards. X-ray micro- and nano-scale computed tomography (CT) imaging led to the development of the digital rock physics subdiscipline in the early 2000s. This has subsequently allowed direct visualization of fluid flow at the pore scale, imaging the wetting phase and multiphase fluid mobility. Multiscale imaging workflows are being developed to overcome issues around heterogeneous rock and the limited field of view associated with the highest resolution X-ray CT images. Hybrid workflows, which combine digital rock physics with traditional core analysis, are becoming increasingly common to meet the challenges associated with some of the most difficult to constrain properties, such as relative permeability. At a larger scale, the recent development of multisensor core logging (MSCL) tools has allowed the cost-effective acquisition of essentially continuous high-resolution 1D, 2D and 3D datasets from both slabbed and unslabbed whole core. Often aided by artificial intelligence to manage and interpret these large physical and chemical datasets, both new and legacy core can be rapidly screened to allow representative subsampling for detailed laboratory experimentation. The context and data provided by the MSCL then allows effective upscaling of these time- and cost-intensive point-source measurements. In the last decade, extended reality (XR) has resulted in a step change in the ability to visualize and integrate core and core-derived information with other subsurface datasets. A very wide range of scales can be managed effectively, from micrometre- to centimetre-scale petrographical and core analysis data, to metre-scale well logs and up to kilometre-scale 3D and 4D seismic. These tools allow stakeholders to work and meet from any location in a common workspace, and efficiently scale and interrogate data in a virtual 3D environment. The various advances in core analysis and associated technologies during the early twenty-first century mean that the study of porous media to help enable the energy transition looks assured. During the coming decades, applications as diverse as carbon capture, utilization and storage (CCUS), hydrogen storage, geothermal energy generation, mining for critical minerals, palaeoclimate studies, radioactive waste management, and site surveys for windfarms will all continue to benefit from the data and understanding derived from core analysis.

Abstract Drill core is a vital resource for subsurface characterization and informs process understanding. However, it is expensive to collect and, as a result, the geoscience community increasingly relies on data from legacy core to address today's energy challenges. Many countries store geological materials collected over decades in national archives. In the UK, over 600 km of drill core is currently stored at the UK national core repository, which covers a breadth of the UK's geology, including those targeted for resources, energy and waste storage. The challenge is to maximize the value of these analogue archives and new core when deposited – improving access to materials and associated data, whilst simultaneously maximizing preservation to ensure optimized use, now and in the future. This paper summarizes the BGS approach to characterize drill core more efficiently and consistently using a multiple-technique core scanning approach set within a project-specific core scanning workflow to increase core data acquisition and complement traditional core characterization practices. Thus, creating a digital record of the core, preserving it beyond its physical lifetime and improving accessibility. This paper highlights the benefits and challenges of this long-term endeavour, especially in making the data open access and discoverable.

Abstract Since 1975, the European Commission has supported research in the field of radioactive waste management and geological disposal through the Euratom Research and Training Programme. During the first two community programmes (1975–85), the research activities focused on basic knowledge, feasibility and safety assessments of such geological disposal repositories. It was during this first decade of collaborative research activities that the site characterization, preliminary design studies and the application for authorization to construct the first underground research laboratory, the High Activity Disposal Experimental Site facility, took place.

Abstract The timeframes involved in nuclear waste management often speak to the imagination, and even transcend it: what does it mean to isolate and contain human-made materials for periods up to hundreds of thousands or even a million years? In this article, we reflect on the role played by the HADES Underground Research Laboratory in making the distant future comprehensible today. Our argument starts by focusing on the pioneering role HADES played and plays in knowledge production on geological disposal. It highlights the heterogeneous nature of scientific experiments and experiences, and the performative role these play in defining matters of concern for research and development. Second, attention is directed to how HADES contributes to the defining of what is considered possible and imaginable, and how it therefore not only renders the future more predictable, but also contributes to the making of that future. We end the paper with a reflection on the implications of what ‘making the future’ could entail from an ethical perspective, discussing how the intergenerational responsibilities that come with these future-making capacities could be handled.

Abstract Geological disposal provides the safe long-term management solution for higher-activity radioactive waste. The development of a repository (or geological disposal facility) requires a systematic and integrated approach, taking into account the characteristics of the waste to be emplaced, the enclosing engineered barriers, and the host rock and its geological setting. Clays and clayey material are important in the development of many national geological disposal systems. Clays exhibit many interesting properties, and are proposed both as host rocks and as material for engineered barriers. Whatever their use, clays present various characteristics that make them high-quality barriers to the migration of radionuclides and chemical contaminants. As host rocks, clays are, in addition, hydrogeologically, geochemically and mechanically stable over geological timescales (i.e. millions of years).

The particle-size distribution of oil-sands tailings has always figured prominently in the mine planning and overall operations and closure strategy in surface-mined oil sands. In oil-sands applications, the convention is to define the sand as the mineral components >44 μm in size and the fines as the mineral component which is <44 μm. The water-based extraction process uses 2 m 3 of water to extract the bitumen from 1 m 3 of oil sand, and as the bulk of this water is recycled, large containment areas are required to maintain a supply of extraction water. A significant proportion of water that is not recycled is retained in both the sand and fines components of the resulting tailings streams and the essence of tailings management comes down to separating and managing the water that can be recovered from the tailings. As the mining operations have become larger, and ore properties vary over wider ranges, the designation of sand and fines was simply inadequate in explaining the behavior of many of the tailings and a thorough understanding of the entire particle-size distribution became more important. Due in part to the upgrading and refinery operations often associated with bitumen production, the oil sands industry is relatively sophisticated in its approach to tailings characterization and tailings management. As a result, any discussion of clays can, and often does, include both a size and mineralogy component. In any case, there is no doubt about the importance of understanding and quantifying the clay component of any tailings stream when defining a dewatering or management strategy. Historically, it might have been argued that the strong correlation between clay content and fines content would be an adequate characterization and tailings-planning parameter. Although this is still largely true, the clay to fines correlations can sometimes be measurably different from operation to operation, resulting in varying tailings performance. In addition, some tailings-management options such as thickeners and centrifuges can separate the fines fraction and even the clay fraction in a fluid fine tailings stream. These upset operational modes can create what are known colloquially as Franken-Fines, a stream with a very disproportionately high clay content that can create an equally disproportionate tailings problem. The tailings strategies that will be discussed include composite/consolidated/non-segregating tailings, thickening, freeze-thaw processes, rim ditching, thin lift dewatering, and centrifugation. The present chapter outlines the evolution of many of these tailings-management strategies that have been tested extensively or are currently in use in the surface-mined oil-sands industry, with a particular emphasis on the importance of understanding the clay size and clay mineralogy in the evaluation and understanding of tailings dewatering performance.