Grant: NE/N016173/1.The data presented herein comprises raw and segmented X-Ray micro-CT data, CMG simulation files and Matlab processing files for the paper 'Representative elementary volumes, hysteresis and heterogeneity in multiphase flow from the pore to continuum scale'. The data is organised as Core 1 and Core 2 respectively. Full core scans are obtained at a resolution of 6 microns. Region of interest (ROI) scans are obtained at 3.45 micron and 2 micon (core 1) and 3.5 micron (core 2). Resolution information is contained within the file names. Voxel sizes in the image files can be changed to match these values. Experimental post-processing files contain the upscaled saturations and porosity values in 3D, which are used in the paper. It also contains the pore-filling analysis. The CMG simulation files contain the input deck, 3D digitial core information (porosity, capillary pressure) needed to simulate both the drainage and imbibition core floods, with corresponding Matlab analysis files. These are Bentheimer outcrop cores obtained from Shell, Amsterdam. It is a shallow marine rock, deposited during the Lower Cretaceous. It outcrops between Enschede and Schoonenbeek in the Netherlands.

Herein lies the supporting data for the paper 'Small-scale capillary heterogeneity linked to rapid plume migration during CO2 storage'. We supply experimental, analytical and numerical simulation data used in the paper. The supplied zipped folders follow the same order as the main paper, with codes to reproduce each figure (and those in the supporting information PDF). There are also video files (in the 5_Field_scale_simulation zipped folder) showing the final CO2 plume evolution from the static images in the main paper Figure 4. Descriptions of each of the folders are given below: 0 - README. This contains detailed instructions on the data and using the supplied files. 1 - Scaling analysis. This contains the scaling analysis analytical methods, with figure generation for Figure 1 in the main paper. 2 - Petrophysics. This contains all the petrophysical experimental data, analysis files and core flood simulation files. This is used to produce Figure 2 in the main paper. 3 - Fine_resolution_simulations. This contains the simulation files, Matlab post processing files and figure generation for the fine resolution simulations, presented in Figure 3 in the main paper. 4 - MIP_upscaling. This contains simulations files, Matlab post processing files and figure generation for the macroscopic invasion percolation scheme. The results of this are presented in the supporting information document. 5 - Field_scale_simulation. This contains the simulations files, Matlab post processing files and figure generation for the final field scale simulations in the main manuscript Figure 4 and in the supporting information. In each folder are separate READMEs containing specific information relevant for the included files.