Pore occupancy of gas hydrate

Area of Science:

• Geochemistry
• Sedimentology
• Thermodynamics

Background:

• Methane hydrates represent a significant portion of Earth's crustal hydrocarbons.
• Their configuration at various scales dictates methane gas release dynamics.

Purpose of the Study:

• To investigate the thermodynamic conditions enabling methane hydrate, water, and gas coexistence in sediments.
• To understand how hydrate pore occupancy varies with depth within the three-phase region.
• To predict the impact of methane hydrates on gas and water flow in porous media.

Main Methods:

• Application of thermodynamic arguments to model methane hydrate behavior.
• Analysis of hydrate pore occupancy based on methane gas density at different depths.
• Estimation of three-phase region thickness in ocean sediments.

Main Results:

• Demonstrated the formation of a three-phase region (hydrate, gas, water) in confined sediment spaces.
• Showed that hydrate pore occupancy is dependent on the depth and methane gas density.
• Estimated the thickness of these three-phase regions in marine sediments.

Conclusions:

• The coexistence of methane hydrate, gas, and water is thermodynamically feasible in ocean sediments.
• Understanding these three-phase regions is crucial for predicting methane release and fluid flow.
• This study provides a framework for assessing the influence of hydrates on subsurface fluid transport.