Experimental and numerical investigations into the influence of temperature on the permeability of sediments containing CO2 hydrate

Abstract

Induced by heat injection or climate change, temperature change in CO₂ hydrate sequestration reservoir significantly affects the permeability, which is crucial for the sealing ability of target reservoir. A combination of experimental tests and fluid-mechanical-thermal coupling simulations is applied to investigate the temperature influence on CO₂ hydrate-bearing sediments. Below the critical temperature for phase transformation, the permeability exhibits a decreasing trend with increasing temperature, demonstrating a quadratic relationship. Moreover, higher hydrate saturation will promote this reduction. In principle, the increase of temperature leads to linear narrowing of pore throats, further causes the quadratic relationship between permeability and temperature. Higher hydrate saturation will increase the thermal expansion and reduce the initial size of pore throats, which results in a more significant temperature sensitivity. The reduction of permeability may inhibit the advancement of decomposition front and enhance the sealing ability. Accordingly, a predictive model is developed to elucidate the relationship between permeability, temperature, and saturation, thereby providing valuable support for the modeling and prevention of CO₂ leakage in marine CO₂ sequestration practices.