Figure 1

Schematic diagram of the experimental apparatus. The $4.7\mathrm{T}$ magnet resides in a small rf shielded room. The remaining equipment was placed outside the room, beyond the $5\mathrm{G}$ line of the magnet. Narrow $1∕8\mathrm{in}$. i.d. Teflon tubing connected all pieces of the apparatus. The tubing length was approximately $2.5\mathrm{m}$ from the polarizer to the sample, and $5\mathrm{m}$ from the sample to the mass flow controller.Reuse & Permissions

Figure 2

Example NMR profiles (i.e., $1\mathrm{D}$ images) of laser-polarized xenon gas flowing through the Austin Chalk sample while applying a CPMG sequence before the image acquisition. The profiles include the regions occupied by the rock sample $\left(z⩾13\mathrm{mm}\right)$ and the Teflon diffuser plate (indicated by the dashed lines). The unattenuated profile $(t_E=2.1\mathrm{ms})$ was obtained after only a single spin-echo before image acquisition. The attenuated profile $\left(tE=33.6\mathrm{ms}\right)$ was acquired after sixteen $180°$ pulses, and is thus heavily $T_2$ weighted. In this profile, the ${}^{129}\mathrm{Xe}$ signal from the rock has completely dephased and is very small, while the ${}^{129}\mathrm{Xe}$ NMR signal from the diffuser plate remains significant. NMR profiles such as these allow $T_2\left(z\right)$ to be determined, and also permit unambiguous identification of the position of the rock core in the experimental apparatus.Reuse & Permissions

Figure 3

Example NMR profiles (i.e., 1D images) of laser-polarized xenon gas flowing through samples of (a) Fontainebleau sandstone and (b) Austin Chalk, with both the gas flow rate and xenon magnetization in steady state. The profiles include the regions occupied by the rock sample ($z⩾13\mathrm{mm}$) and the Teflon diffuser plate (indicated by dashed lines). The bold lines show the profiles corrected for gas density and polarization variation in the rock. For such typical NMR profiles, we averaged 32 signal acquisitions, each made with $t_E=2.1\mathrm{ms}$, and achieved a 1D spatial resolution of approximately $1\mathrm{mm}$.Reuse & Permissions

Figure 4

Examples of ${}^{129}\mathrm{Xe}$ NMR profiles used in the permeability measurements: (a) Fontainebleau sandstone; (b) Austin Chalk. Profiles shown in solid lines correspond to different delay times $\tau$, following a sequence of rf and gradient pulses to quench all xenon magnetization in the sample. The dash lines are profiles corrected for gas density and polarization variation.Reuse & Permissions