Permeability of Porous Media in the Presence of Gas Hydrates

Gas hydrates which form at high pressure and low temperature conditions, are solid crystalline compounds comprised of a lattice of water molecules that encage gas molecules. Gas hydrates impact society because of their potential as an immense energy source and their role in submarine geohazards. Economical production of natural gas from hydrate reservoirs crucially depends on the formation permeability and the relative permeability of the sediment to fluid flow. Permeability measurements from natural core samples are difficult owing to core disturbance during retrieval and processing. Laboratory synthesized samples provides a viable alternative with the flexibility to form samples with desired morphology and mineralogy. Unfortunately, very few permeability and relative permeability measurements have been performed and thus the range of media properties and saturations expected in natural hydrate bearing sediments is not available. In the absence of reliable experimental data, numerical reservoir simulators employ theoretical models for permeability prediction. However, experimental verification of the theoretical models is still required.;This thesis focuses on understanding the effect of hydrate formation on the relative permeability of porous media to fluid flow. In doing so, a better way to evaluate the suitability of the existing theoretical models has been developed. It also explores if better permeability prediction can be achieved using a combination of available theoretical models. Finally, an experimental program in which relative permeability of porous media in the presence of carbon dioxide hydrate was performed and the results analyzed within the proposed framework of modeling and evaluating theoretical permeability predictions.