Influence of core scale permeability on gas production from methane hydrate by thermal stimulation

Abstract The hydrate dissociation process involves heat transfer in the decomposing zone, multi-phase fluid flow during gas production, and the intrinsic kinetics of hydrate dissociation. The potential impact of laboratory-scale permeability on hydrate exploitation from hydrate-bearing sediments was predicted from a previously developed and verified two-dimensional axisymmetric model. We herein continue the previous work to investigate the influence of core-scale hydrate sediments’ permeability on gas production by the thermal stimulation method. The results show that the gas production in relatively low permeability reservoirs proceeded at a faster rate, requiring less time to complete the dissociation process, although an optimal permeability was associated with the fastest gas production. In addition, with the temperature continuously increased, the dissociation front displaced from the boundary wall to the core axis along the radial direction. In a lower permeability system, however, the hydrate dissociation process at the zone opposite the outlet valve was delayed. Due to the varying processes associated with hydrate dissociation, the overall thermal conductivity declined faster at an earlier stage in sediments of high permeability as compared with sediments of lower permeability. Furthermore, the effects of boundary heat transfer were more significant for low permeability systems.