DOI: 10.25911/6181fc5c9b8ed
title: Processed 3D Tomographic Images of Cyclic CO2 and Brine injections into Bentheimer Sandstone

description: This data arises from a series of core-flooding experiments intended to inform knowedge of carbon dioxide (CO2) sequestration in geologic reservoirs. Four cycles of supercritical CO2 ("scCO2") and 1.0 M KI brine injections were undertaken in a Bentheimer sandtsone core under reservoir-relevant temperature and pressure conditions (40 deg C, 1250PSI/8.6 MPa). 3D X-ray tomograms were acquired at the endpoint of every injection process. Scanning was undertaken using the in-house developed high-pressure core-flooding apparatus at the ANU CTLab at a resolution of 3.74978 micron/voxel edge.
description: This data arises from a series of core-flooding experiments intended to inform knowedge of carbon dioxide (CO2) sequestration in geologic reservoirs. Four cycles of supercritical CO2 ("scCO2") and 1.0 M KI brine injections were undertaken in a Bentheimer sandtsone core under reservoir-relevant temperature and pressure conditions (40 deg C, 1250PSI/8.6 MPa). 3D X-ray tomograms were acquired at the endpoint of every injection process. Scanning was undertaken using the in-house developed high-pressure core-flooding apparatus at the ANU CTLab at a resolution of 3.74978 micron/voxel edge. The raw grayscale tomographic data volumes for all "initial" (post-CO2 injection) and "residual" (post-brine injection) scans were first registered to the dry tomographic data set to allow direct and precise comparison of phase distributions in each data set. Data volumes were cropped to a central region, and grayscale intensity variation (due to beam hardening and attenuation distortion due to high-density flow diffusers at the core ends) was corrected in radial and vertical directions. The dry scan was segmented into three phases (pore, solid grains, and clays) using converging active contours "CAC") segmentation routines. Four-phase segmentation (scCO2, brine, solid grains, and clays) was accomplished by overlaying the phase-labeled dry data set on all the registered initial and residual data volumes, and performing a final additional CAC routine to distinguish between scCO2 and brine, only on the regions labeled "pore" in the dry data set. Speckle noise removal was accomplished by removing scCO2-labeled clusters smaller than 268 voxels (equivalent to a sphere with a radius of 15.0 micron), and also by removing any isolated inclusions from within the scCO2 phase. The final data volumes used for quantitative analysis were cylinders with a diameter of 8.14 mm and a height of 27.3 mm, equivalent to a physical volume of 1,420 cubic mm (or 2.69 X 10^10) voxels); and had an image-based porosity of 21.3%. Data is segmented and in .nc format (https://www.unidata.ucar.edu/software/netcdf/). For "DRY" data set: 0=void/pore space; 1=Sandstone grains; 2=clays. For initial ("SI#") and residual (SR#) data: 0=scCO2; 1=brine; 2=sandstone grains; 3=clays Full experimental and analytical details are included in: A.L. Herring, R.T. Sun, C. Armstrong, Z. Li, J.E. McClure, M. Saadatfar, Evolution of Bentheimer Sandstone Wettability During Cyclic scCO2-Brine Injections, Water Resour. Res. (2021).