Table 1 Volume fraction of microstructural constituents assumed to be equivalent to the area fraction inferred from the elemental maps after image segmentation like that shown in Fig. 3. Also shown are the values for the indentation modulus measured during nanoindentation for each constituent. The values in parenthesis are inferred by accounting for the microcrack compliance as discussed in the supplementary information (see Microcrack stiffness section, Eq. S9).
From: Origins of pressure dependent permeability in unconventional hydrocarbon reservoirs
Sample | Volume fraction of relevant microstructural constituents | |||||
|---|---|---|---|---|---|---|
Clay | Cement clay | Quartz grain supported | Calcite grain supported | Calcite inclusions | Microcrack | |
Bakken | – | – | – | 1 | – | – |
Bakken w/inclusions | 0.057 | – | – | 0.943 | – | – |
Mancos | 0.65 | – | 0.35 | – | – | – |
Wolfcamp cemented | – | 0.77 | – | – | 0.23 | (0.015) |
Wolfcamp | 0.98 | – | – | – | – | 0.02 |
Compliance, CP or CS (GPa−1) | ||||||
Nanoindentation | 0.04 ± 0.013 | 0.015 ± 0.002 | 0.017 ± 0.002 | 0.021 ± 0.04 | 0.014 ± 0.002 | 0.089 ± 0.01 |
Literature | 0.05 ± 0.01332 | CP > CS = 0.02734 | CP > CS = 0.01434 | CS = 0.01434 | ||
Crack mechanics | (23) | |||||
