Investigation of the impact of threshold pressure gradient on gas production from hydrate deposits

•The TPG and the permeability-viscosity ratio agree well with a power law function.•The TPG plays a critical role in gas production from hydrate-bearing sediments with unconsolidated argillaceous siltstones.•A small TPG can effectively expand the gas output, which can expand the three-phase coexisting area.•When the production well does not completely drill out the hydrate layer, the bottom water invasion would appear. The TPG can restrict the aquifer invading into hydrate layer.