Estimation and measurement of permeability inside methane hydrate mimicking porous media

Abstract

The objective of this study is to mimic methane hydrate cores at atmospheric pressure conditions with the same permeability as oceanic methane hydrate cores. This became possible by freezing a solution of water, ethanol, and sodium bicarbonate in Toyoura sand at -10°C. First, partial freeze was measured and theoretically evaluated in a solution of water, NaHCO3 and ethanol. Then, the permeability of the methane hydrate core mimicking samples was evaluated based on the partial freeze evaluation. Finally, the permeability of the methane hydrate core mimicking samples was measured by injecting a solution of water and ethanol at -10°C inside the partially frozen samples. The experimental results suggested that it is possible to control the permeability of the created porous media by changing the volume fraction of ethanol in the solution. Furthermore, the permeability of the methane hydrate core mimicking samples was of the same order as that of real oceanic methane hydrate cores for a weight percent of ethanol in the solution of 8wt%.

Keywords

• methane hydrate
• porous media
• permeability
• control
• freezing point
• fractional freezing