Composite Sensible Heat Effect of Burial Depth on Gas Production from Hydrate-Bearing Sediments

The impact of sensible heat on the gas production from different hydrate-bearing sediments is only partially understood, and whether it will affect the production performance from different burial hydrates remains unknown. In this study, we proposed a dynamic composite sensible heat calculation method that incorporates in situ hydrate and the unrecovered water. Furthermore, a water-hydrate-gas saturation calculation method was introduced, which considered dissolved methane in the water phase. Five hydrate-bearing layers, ranging in burial depth from 570 to 856 m, were synthesized with similar hydrate saturation for consistency. By employing two types of depressurization perturbations to these hydrate-bearing systems, the results show an increase in the composite sensible heat with the burial depth regardless of the dissociation method during depressurization. The elevated composite sensible heat correlates with higher gas production when the same depressurization pressure was employed. Consequently, priority should be given to the shallow to moderately burial reservoirs in the selection of hydrate production targets.