Measurements of CH4 and CO2 relative permeability in hydrate-bearing sandstone

This paper reports measurements of relative permeability to methane (CH4) and carbon dioxide (CO2) in hydrate-bearing sandstone core samples. The CH4 (or CO2) permeability was measured at reservoir conditions for different hydrate and brine saturations. The saturation span ranged from 0.18 to 0.60 (frac.) for CH4 gas and from 0.37 to 0.70 (frac.) for liquid CO2. The hydrate saturation ranged from 0.18 to 0.61 (frac.). The growth of hydrates within sandstone pores reduced the permeability for both the CH4 and CO2 system significantly, and the relative reduction was more pronounced for lower gas saturations. This effect is currently not included in numerical models of relative permeability in hydrate-bearing sediments and should be considered. The reported measurements are relevant to production-forecasting of methane gas from hydrate reservoirs and CO2 storage schemes where CO2 hydrates may provide self-sealing in cold aquifers.