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    Data generated at UCL on a conventional triaxial apparatus. The data includes the 'raw' data, as well as semi-processed data used to plot figures and draw main conclusions. This dataset is used and fully described/interpreted in the paper: M. Jefferd, N. Brantut, P.G. Meredith and T.M. Mitchell, Compactive Deformation of Sandstone under Crustal Pressure and Temperature Conditionsserpentinite, submitted to J. Geophys. Res. And in the UCL PhD Thesis M.Jefferd, Sandstone under Crustal Pressure and Temperature

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    Field photographs of rock formations or modern precipitates from the sedimentary environment. Samples were collected throughout the UK. This data was collected between February 2019 and November 2019. This data was collected to better understand the low temperature cycling of Telurium (Te) and Sellenium (Se) in the geological environment. For example, a range of ochre samples were included in this data. Ochres are a modern precipitate commonly found in rivers and streams which flow through geographical areas with a history of mining resources which are rich in sulphides. Iron from the sulphides are leached out and deposited downstream, coating river and stream beds, giving a red, yellow or orange colouration. Ochres can be a sink for trace metals such as Te and Se, therefore studying these environments could be informative from a resource perspective but also from an environmental hazard perspective. This data would be useful for researchers who require reference photographs for similar studies or as an aid for resampling.

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    Data recorded during hydrostatic pressurisation and triaxial rock deformation experiments of Westerly granite and Darley Dale sandstone. Data consists of mechanical data (load, displacement, confining pressure) and pore pressure data (up- and downstream pore pressure, upstream intensifier volume, four pore pressure transducers mounted on sample). Contains all data necessary to evaluate the results presented in the paper entitled: 'Fluid pressure heterogeneity during fluid flow in rocks: New laboratory measurement device and method' by Brantut and Aben, submitted to Geophysical Journal International, and available at arXiv (arXiv:2006.16699).

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    The spreadsheet gathers the data collected during a brine:CO2 flow-through experiment conducted on a weakly-cemented synthetic sandstone core sample using the multiflow experimental rig for CO2 experiments, designed and assembled at the National Oceanography Centre, Southampton. The test was configured to assess geophysical monitoring and deformation of reservoirs subjected to CO2 injection in shallow weakly-cemented (North Sea-like, e.g., Sleipner) CO2 storage sandstone reservoirs. The tests was conducted in the rock physics laboratory at the National Oceanography Centre, Southampton, during 2015-2016, as part of the DiSECCS project with funding from the United Kingdom’s Engineering and Physical Sciences Research Council (EPSRC grant EP/K035878/1) and the Natural Environment Research Council (NERC). The experiment was a steady state brine-CO2 flow-through test in which realistic shallow CO2 geosequestration conditions were simulated, to related geophysical signatures to the hydrodynamic and geomechanical behaviour of the rock sample. The confining and pore pressure conditions were similar to those estimated for shallow North Sea Sleipner-like, storage reservoirs, but simulating inflation/depletion cyclic scenarios for increasing brine:CO2 fractional flow rates. The data include ultrasonic P- and S-wave velocities and their respective attenuation factors, axial, radial and volumetric strains, and electrical resistivity; also relative permeability to both fluids (CO2 and brine) is displayed as a function of pore volume times, associated to increasing CO2 to brine contents in the sample.

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    EPSRC grant EP/L012227/1: Development of Unified Experimental and Theoretical Approach to Predict Reactive Transport in Subsurface Porous Media. The effect of pore-scale heterogeneity on non-Darcy flow behaviour is investigated by means of direct flow simulations on 3-D images of Bentheimer sandstone and Estaillades carbonate. The critical Reynolds number indicating the cessation of the creeping Darcy flow regime in Estaillades carbonate is two orders of magnitude smaller than in Bentheimer sandstone, and is three orders of magnitude smaller than in the beadpack. Also available at https://www.digitalrocksportal.org/projects/11, DOI:10.17612/P77P49. Further details can be found in Bagus P. Muljadi, Martin J. Blunt, Ali Q. Raeini, Branko Bijeljic. The impact of porous media heterogeneity on non-Darcy flow behaviour from pore-scale simulation. Advances in Water Resources. 2015. http://dx.doi.org/10.1016/j.advwatres.2015.05.019.

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    P* data obtained through hydrostatic loading experiments, using triaxial experimental apparatus, as well as yield curve data obtained through differential loading tests, prior to the discovery of P* for different synthetic sandstones. The methodology used was taken from Bedford et al. (2018, 2019). Grain size analysis data obtained using a Beckman Coulter LS 13 320 laser diffraction particle size analyser. Particle analysis was conducted on five different synthetic sandstones with different grain size distributions. Secondary electron and backscatter electron SEM images for natural and synthetic sandstones. Secondary electron images were stitched together to form a whole core image. They were then binarised following the methodology of Rabbani and Ayatollahi. (2015). Hexagon grid size data used to obtain the correct grid size for performing porosity analysis across an mage using Fiji software (Brown, 2000). Bedford, J. D., Faulkner, D. R., Leclère, H., & Wheeler, J. (2018). High-Resolution Mapping of Yield Curve Shape and Evolution for Porous Rock: The Effect of Inelastic Compaction on 476 Porous Bassanite. Journal of Geophysical Research: Solid Earth, 123(2), 1217–1234. Bedford, J. D., Faulkner, D. R., Wheeler, J., & Leclère, H. (2019). High-resolution mapping of yield curve shape and evolution for high porosity sandstone. Journal of Geophysical Research: Solid Earth. Brown, G. O., Hsieh, H. T., & Lucero, D. A. (2000). Evaluation of laboratory dolomite core sample size using representative elementary volume concepts. Water Resources Research, 36(5), 484 1199–1207. Rabbani, A., & Ayatollahi, S. (2015). Comparing three image processing algorithms to estimate the grain-size distribution of porous rocks from binary 2D images and sensitivity analysis of the grain overlapping degree. Special Topics & Reviews in Porous Media: An International Journal, 6(1).

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    UKGEOS and Core Sample Analysis. Geomechanical testing was performed to determine triaxial compressional strength, tensile strength, frictional strength and permeability of sandstones, siltstones, mudstones and coals from eleven depth intervals within the GGC01 borehole, UK Geoenergy Observatories (UKGEOS), Glasgow, United Kingdom. Frictional strength tests were also performed on cuttings samples of sandstones, siltstones, mudstones and coals from the GGA08 borehole, Glasgow, United Kingdom. In total twenty-three tensile strength tests were performed on ten sampled intervals, and seven porosity measurements pre-and post-failure were taken. Nine triaxial compressive strength tests and twenty-one frictional strength tests were performed, with permeability measured both before and after failure or shear respectively. From compressive strength tests we also determined the Young’s modulus and Poisson’s ratio. Results of X-Ray Diffraction are also included in the dataset.