Processed 3D Tomographic Images of Repeated CO2 and Brine injections into Layered Bentheimer Sandstone

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. Three-phase segmentation (scCO2, brine, solid grains) 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 234 voxels (equivalent to a sphere with a radius of 15.0 micron), and also by removing any isolated inclusions from within the scCO2 phase.

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
For initial ("SI#") and residual (SR#) data: 0=scCO2; 1=brine; 2=sandstone grains

1000^3 voxel subsets of data were taken from the "top", "middle", and "bottom" regions of the core; these subsets are provided here. Data is labeled with the following nomenclature:
segmentedHiRes_roi_CO2_injection_1_a_SStop_nc
segmentedHiRes_roi_Brine_injection_1_SStop_nc

"CO2" or "Brine" indicates the type of injection directly preceeding the scan acquisition; the numeral [1-4] indicates the cycle number, the letter [a-d] desginates the sequence of CO2 injections (for cycles with repeated CO2 injections) ; and the region is indicated directly. Full experimental details (including flow rates and scan types) are included in:
A.L. Herring, Sun, C., Armstrong, R.T., and Saadatfar, M. "Insights into Wettability Alteration during Cyclic
scCO2-Brine Injections in a Layered Bentheimer Sandstone", International Journal Greenhouse Gas Control (2022), DOI:10.1016/j.ijggc.2022.103803.

所有“初始”（二氧化碳注入后）与“残余”（盐水注入后）扫描的原始灰度断层扫描数据体，首先配准至干燥断层扫描数据集，以实现各数据集内相分布的直接且精准对比。随后将数据体裁剪至中心区域，并在径向与垂向上校正灰度强度畸变——该畸变由束流硬化以及岩心端部高密度流动扩散器引发的衰减畸变导致。研究人员利用收敛主动轮廓（converging active contours, CAC）分割算法，将干燥扫描数据体分割为三相：孔隙、固体颗粒与黏土。通过将带相标签的干燥数据集叠加至所有配准后的初始与残余数据体，并仅针对干燥数据集中标记为“孔隙”的区域执行最终的额外CAC分割流程，最终完成了三相分割（超临界二氧化碳scCO₂、盐水、固体颗粒）。斑点噪声去除通过两步实现：一是移除尺寸小于234体素（voxel，等价于半径15.0微米的球体）的scCO₂标记簇，二是移除scCO₂相内的所有孤立包裹体。

数据已完成分割，采用.nc格式（即网络通用数据格式NetCDF，详见https://www.unidata.ucar.edu/software/netcdf/）。针对“DRY”数据集：0代表孔隙空间；1代表砂岩颗粒。针对初始（“SI#”）与残余（“SR#”）数据：0代表scCO₂；1代表盐水；2代表砂岩颗粒。

研究人员从岩心的“顶部”“中部”与“底部”区域截取了1000³体素的数据子集，本数据集即提供此类子集。数据采用以下命名规则："segmentedHiRes_roi_CO2_injection_1_a_SStop_nc"、"segmentedHiRes_roi_Brine_injection_1_SStop_nc"。其中“CO₂”或“Brine”代表扫描采集前直接注入的流体类型；数字[1-4]代表循环次数；字母[a-d]用于标识二氧化碳注入序列（针对存在重复二氧化碳注入的循环）；区域信息则直接体现在命名中。

完整实验细节（包括流速与扫描类型）详见下述文献：A.L. Herring、Sun C.、Armstrong R.T. 与 Saadatfar M.，《层状本特海姆砂岩中循环超临界二氧化碳-盐水注入过程的润湿性改变研究》，《国际温室气体控制期刊（International Journal Greenhouse Gas Control）》，2022年，DOI:10.1016/j.ijggc.2022.103803。