Hydrate is a Nonwetting Phase in Porous Media

Abstract

In porous media containing gas hydrate, the hydrate morphology impacts the flow behavior of the fluid phases. We hypothesize that hydrate emplaces itself as a nonwetting phase and use this idea to describe relative permeability of water in a hydrate/water system. We perform steady‐state relative permeability measurements in hydrate‐bearing samples with a range of hydrate saturation. We measure and compare water relative permeability in the presence of gas and in the presence of hydrate and find that the water relative permeability is the same in both cases. This suggests that (1) relative permeability for hydrate systems can be obtained without performing difficult experiments on hydrate bearing sediments, (2) flow properties are porous‐media dependent, and (3) models that assume a fixed pore or tube geometry are inadequate.

Three‐Dimensional Free Gas Flow Focuses Basin‐Wide Microbial Methane to Concentrated Methane Hydrate Reservoirs in Geological System

“…We set the permeability and capillary entry pressure of pure methane hydrate to 10 −17 m 2 and 0.2 MPa, respectively. With these values, the predicted decrease in permeability by hydrate formation (Table 1) matches the laboratory measurements on hydrate-bearing Berea sandstone (Figure 5a; Murphy et al, 2020); the predicted increase in capillary entry pressure by hydrate (Table 1) is close to the prediction assuming that hydrates fill the center of pores when hydrate saturation is <60% (Figure 5b; Kleinberg & Griffin, 2005).…”

“…The black line is predicted by PetroMod™ with pure methane hydrate permeability equaling 10 −17 m 2 . The blue line is predicted by the Brook‐Corey model that fits the laboratory measurements on hydrate‐bearing Berea sandstone, assuming hydrate is nonwetting phase and fills the large pores of the sediment (Murphy et al., 2020). (b) Ratio of the hydrate‐bearing sediment capillary entry pressure to the hydrate‐free sediment (Table 1).…”

Influence of Rock Wettability on THF Hydrate Saturation and Distribution in Sandstones

“…Methane hydrates contribute a significant share to the global carbon budget, with approximately 3 × 10 14 m 3 of methane gas trapped in geologic hydrate accumulations . The presence of these vast amounts of methane in hydrate-bearing reservoirs has encouraged major research in this area, related to energy production, − CO 2 sequestration, − and climate change. − One such key hydrate accumulation is coarse-grained hydrate-bearing sediments. Hydrate formation, dissociation, and associated geologic and production timescales are controlled by fluid flow properties through the sediment …”

“…Emplacement of hydrate can be considered an alteration of the pore space with related changes in porosity and permeability . Related models for predicting the associated permeabilities and porosities have been developed; ,− however, these permeability models are affected by the wettability of the porous medium . Consequently, a key input parameter into these models is the spatial position of the hydrate in the pore space of the rock, which is closely related to the hydrate wettability of the rock (i.e., the affinity of the hydrate to the rock surface).…”

Estimating Permeability of Partially Frozen Soil Using Floating Random Walks

“…Because of the extensive presence of fluid flow and reactive transport, predicting the spatially distributed permeability with reasonably good accuracy is crucial to the Earth science community and beyond. Previous researchers have built upon pioneering treatments of the relation between k r and the saturation level of an additional nonwetting fluid phase (e.g., Brooks & Corey, 1964; van Genuchten, 1980), to consider how k r varies with the saturation level of a solid, such as hydrate (e.g., Brooks & Corey, 1964; Kleinberg et al., 2003; Kumar et al., 2010; Liang et al., 2011; Murphy et al., 2020; Ordonez et al., 2009) or ice (e.g., Chamberlain & Gow, 1979; Horiguchi & Miller, 1983; Watanabe & Osada, 2016). Empirical correlations based on these findings are commonly employed in the oil industry (see Lee, 2008).…”