This dataset contains results from nanoindentation testing of five shale samples from the Horn River Basin (core from wells A100B/94 and D94A/94). The samples are from the following formations: A3 Fort Simpson, A6 Fort Simpson, D1 Muskwa, A16 Otter Park, and A20 Evie. The data is in two sets. Set 1 includes nanoindentation data from all samples, with grids conducted both parallel and perpendicular to the bedding plane. In Set 2, additional chemical analysis of select grids (on samples A3, A6 and A20) was undertaken using SEM/EDS. Both sets include the following tab-separated .txt files: grid_para.txt [Load-displacement-time data for each indent (parallel indentation)]; grid_para_summary.txt [Reduced elastic modulus, hardness and creep modulus for each indent (parallel indentation)]; grid_perp.txt [Load-displacement-time data for each indent (perpendicular indentation)]; grid_perp_summary.txt [Reduced elastic modulus, hardness and creep modulus data for each indent (parallel indentation)]. Set 2 also includes .tif files containing SEM images and EDS chemical analysis of the grids. The data has been filtered to remove indents which show 'pop-in' behaviour or time-displacement curves that do not conform to a logarithmic fit. ACKNOWLEDGMENT - The authors wish to thank the Natural Environment Research Council (NERC) for funding this research through the SHAPE-UK project (grant numbers NE/R018057/1, NE/R017840/1, and NE/R017565/1), which forms Challenge 3 of the UKUH (Unconventional Hydrocarbons in the UK Energy System) programme.

Major, trace element and REE analyses of muds and mudstones from selected intervals from all of the holes. Location of the drill holes are given in the Exp. 352 cruise report (Reagan et al)

Geomechanical strength data of mudstone samples collected from the Gunthorpe Member, of the Sidmouth Mudstone Formation of the Mercia Mudstone Group. Testing includes Uniaxial Compressive Strength (UCS), Indirect Tensile Strength (ITS) and Triaxial strength testing completed at the University of Leeds (UoL) and Point Load testing and thermal loading testing completed at the British Geological Survey (BGS). All sample preparation, preservation and testing were completed to the specification outlined by the ISRM (2007) unless otherwise stated. For all Triaxial testing, each sample was deformed under standard triaxial stress conditions, where the primary principal stress corresponds to the axial stress and the intermediate and minimum principal stresses are equal to that of the confining pressure. The data are separated into individual Excel files (.xlsx), with each file representing a single test. Each file contains time, force, stress, displacement, and strain data.

Stress-Dependent permeability data for samples of the Glasgow Main coal and the overlying mudstone and sandstone from the UKGEOS research borehole GGC01. Associated XRD mineralogy, Helium Porosity, bulk and matrix densities are also included. Samples and data are derived from the UK Geoenergy Observatories Programme funded by the UKRI Natural Environment Research Council and delivered by the British Geological Survey.

Geomechanical strength data of mudstone samples collected from the Grey Shale Member of the Whitby Mudstone Formation of the Lias Group. Testing includes cyclic thermo-mechanical loading completed at the British Geological Survey (BGS). All sample preparation, preservation and testing were completed to the specification outlined by the ISRM (ISRM, 1978b; ISRM, 1978a; Bieniawski and Bernede, 1979; ISRM, 1985 for determining the indirect tensile strength, triaxial strength, UCS and point load strength respectively) unless otherwise stated. Each test was comprised of three main stages: 1) A heating stage where the sample is heated to a set temperature loading scheme under pressure conditions of 1-1.4 MPa axial stress and 0.5 MPa confining pressure throughout the heating stage 2) A preloading stage, where the confining pressure is increased to 5 MPa which was held throughout the triaxial compression test. 3) Triaxial compression test, during the active deformation phase, the samples were axially loaded using a constant displacement rate of 0.0012 mm s-1. The data are separated into individual Microsoft Excel files, with each file representing a single test. Each file contains time, force, stress, displacement, and strain data.

Geomechanical strength data of mudstone samples collected from the Gunthorpe Member, of the Sidmouth Mudstone Formation of the Mercia Mudstone Group. The testing was completed at the British Geological Survey (BGS). All sample preparation, preservation and testing were completed to the specification outlined by the ISRM (ISRM, 1978b; ISRM, 1978a; Bieniawski and Bernede, 1979; ISRM, 1985 for determining the indirect tensile strength, triaxial strength, UCS and point load strength respectively) unless otherwise stated. Each test was comprised of three main stages: 1) A heating stage where the sample is heated to a set temperature loading scheme under pressure conditions of 1-1.4 MPa axial stress and 0.5 MPa confining pressure throughout the heating stage 2) A preloading stage, where the confining pressure is increased to 5 MPa which was held throughout the triaxial compression test. 3) Triaxial compression test, during the active deformation phase, the samples were axially loaded using a constant displacement rate of 0.0012 mm s-1. The data are separated into individual Microsoft Excel files, with each file representing a single test. Each file contains time, force, stress, displacement, and strain data. The data are separated into individual Excel files (.xlsx), with each file representing a single test. Each file contains time, force, stress, displacement, and strain data.

Geomechanical strength data of mudstone samples collected from the Grey Shale Member, of the Whitby Mudstone Formation of the Lias Group. Testing includes Uniaxial Compressive Strength (UCS), Indirect Tensile Strength (ITS) and Triaxial strength testing completed at the University of Leeds (UoL) and Point Load testing completed at the British Geological Survey (BGS). All sample preparation, preservation and testing were completed to the specification outlined by the ISRM (2007) unless otherwise stated. For all Triaxial testing, each sample was deformed under standard triaxial stress conditions, where the primary principal stress corresponds to the axial stress and the intermediate and minimum principal stresses are equal to that of the confining pressure. The data are separated into individual Excel files (.xlsx), with each file representing a single test. Each file contains time, force, stress, displacement, and strain data.

This data set consists of thermal property testing results including thermal conductivity, thermal diffusivity, porosity, permeability and density. The data is presented in an excel spreadsheet with two tabs, one containing the data itself and one containing a description of each column. The testing was carried out on behalf of the BGS Geothermal and energy storage programs between 2020 and 2025. The samples were predominantly plugs (24x38mm) or wedges (usually quarter core of various lengths) taken from borehole core. The following boreholes were sampled as part of the project. • UKGEOS CHESHIRE A-101 • Frodsham Marsh • Stanlow • Killingholme DG1 • Speke Reservoir • Carnaby • UKGEOS GGC01 • KEYWORTH D (GSHP 3) • SUTTON BONINGTON SB4 These sites were chosen to support characterisation activities around BGS projects such as the UK GeoEnergy Observatories project and the drilling of a ground source heat well on site at BGS Keyworth.

A brief description of ten core plug samples collected from borehole GGC01 (Glasgow, United Kingdom) is provided, as well as for twelve 15-50 g cuttings samples from 1m intervals within borehole GGA08. Samples were also collected from borehole GGA02 but not used for further analyses. Data comprise results from geomechanical tests, permeability and porosity measurements, and X-Ray Diffraction analyses performed on drillcore samples of sandstones, siltstones, mudstones and coals from eleven depth intervals within the GGC01 borehole. Geomechanical data include triaxial compressional strength, tensile strength, and frictional strength. Frictional strength data was also collected for cuttings samples of sandstones, siltstones, mudstones and coals from the GGA08 borehole. 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. Samples and data are derived from the UK Geoenergy Observatories Programme funded by the UKRI Natural Environment Research Council and delivered by the British Geological Survey.

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.