Thermal　stimulation　via　injecting　hot　water　can　assist　depressurization　in　natural　gas　hydrate　(NGH)　exploitation.　However,　whether　depressurization　coupled　with　the　thermal　stimulation　(DP　+　TS)　model　can　enhance　gas　production　in　muddy　silt　NGH　reservoirs　is　still　debated.　In　this　study,　we　aimed　to　perfect　research　on　the　DP　+　TS　model　by　proposing　a　hydro-lock　effect　that　can　delay　pressure　propagation　and　hinder　heat　and　mass　transfer　in　NGH　reservoirs.　In　addition,　we　established　a　THMC　model　to　simulate　NGH　reservoirs　located　at　Site　W17　to　investigate　the　production　enhancement　of　the　DP　+　TS　model　in　the　initial　state　and　the　hydraulic　fracturing　state.　Results　indicate　that　(i)　injecting　water　into　reservoirs　may　cause　pressure-holding,　NGH　reformation,　and　permeability　damage,　making　the　DP　+　TS　model　fail　to　enhance　gas　recovery　and　produce　additional　water.　(ii)　Hydraulic　fracturing　enhances　permeability,　maintaining　higher　hot　water　injection　rates,　easing　hydro-lock,　and　promoting　efficient　heat　and　mass　transfer.　(iii)　The　DP　+　TS　model　can　only　enhance　production　when　the　permeability　of　the　fractured　area　exceeds　a　certain　value,　but　its　energy　efficiency　is　still　lower　than　that　of　pure　depressurization.　These　key　findings　can　fill　knowledge　gaps　in　the　DP　+　TS　model　and　provide　guidance　in　future　NGH　exploitation.　©　2025　Elsevier　Ltd