Gas hydrate reservoirs represent a significant unconventional energy resource, but their production behavior is strongly influenced by hydrate dissociation processes that generate a moving interface between dissociated and intact zones. T his dynamic boundary alters the transient pressure and rate responses of the reservoir, making conventional well-test interpretation methods difficult to apply.

 In this work, an analytical methodology for the interpretation of transient pressure and rate tests in gas hydrate reservoirs is developed using the Tiab Direct Synthesis (TDS) technique. The formulation is based on a radial composite reservoir model with a dynamic dissociation interface proposed by Chen et al. [1]. By analyzing pseudo pressure, reciprocal rate, and their first- and second-order derivatives, characteristic points associated with hydrate dissociation dynamics are identified without the need for type-curve matching.

 Using synthetic data generated from the analytical model, new explicit mathematical expressions were derived to estimate key reservoir parameters, including the dimensionless dissociation radius, the dissociation factor, and the interzonal storage ratio. The analysis demonstrates that the second-derivative functions provide clearer diagnostic features, such as local Minima and power-law slopes, which facilitate the identification of flow regimes and improve parameter estimation.

 T he proposed methodology successfully reproduces the dominant dynamics of hydrate reservoirs with moving dissociation fronts and provides reliable estimates of the governing parameters. These results demonstrate that the TDS based framework offers a practical and fully analytical alternative for the interpretation of transient tests in hydrate-bearing formations.