Interaction of Hydrocarbons with Clays under Reservoir
Conditions: In Situ Infrared and Nuclear Magnetic Resonance Spectroscopy
and X‑ray Diffraction for Expandable Clays with Variably Wet
Supercritical Methane
Geoffrey M. Bowers
John S. Loring
H. Todd Schaef
Eric D. Walter
Sarah D. Burton
David W. Hoyt
Sydney S. Cunniff
Narasimhan Loganathan
R. James Kirkpatrick
10.1021/acsearthspacechem.8b00039.s001
https://acs.figshare.com/articles/journal_contribution/Interaction_of_Hydrocarbons_with_Clays_under_Reservoir_Conditions_In_Situ_Infrared_and_Nuclear_Magnetic_Resonance_Spectroscopy_and_X_ray_Diffraction_for_Expandable_Clays_with_Variably_Wet_Supercritical_Methane/6275927
The
results from novel in situ high-pressure nuclear magnetic resonance
(NMR) spectroscopy, infrared (IR) spectroscopy, and X-ray diffraction
(XRD) investigation of the interaction of the smectite hectorite with
variably wet supercritical methane (scCH<sub>4</sub>) at 90 bar and
323 K (hydrostatic conditions equivalent to ∼1 km depth) show
that CH<sub>4</sub> occurs in the clay interlayers, in pores external
to the individual clay particles, and as bulk fluid. The occupancy
of each environment depends on the relative humidity (RH) of the CH<sub>4</sub>-rich fluid and the hydration energy and size of the charge-balancing
cation. As RH increases, the fraction of interlayer and interparticle
CH<sub>4</sub> decreases, although with Cs<sup>+</sup>, addition of
a small amount of H<sub>2</sub>O initially increases CH<sub>4</sub> uptake. Maximum interlayer CH<sub>4</sub> adsorption occurs when
the mean basal spacing just permits methane intercalation (∼11.5
Å) and never below this basal spacing. It is also higher with
divalent cations than with monovalent cations. The data show that
CH<sub>4</sub> adsorption occurs predominantly via a weak dispersion
interaction with the clay and that its intercalation occurs via a
passive space-filling hydrophobic mechanism. The results suggest that,
under reservoir conditions, smectite interlayers may provide a reservoir
for CH<sub>4</sub> under low-water conditions.
2018-05-07 00:00:00
RH
CH 4 adsorption
clay
Maximum interlayer CH 4 adsorption
XRD
CH 4
basal spacing
H 2 O
increases CH 4 uptake
NMR
cation
IR
interparticle CH 4 decreases