Spatiotemporal Instabilities in the Nonlinear Dynamics of the Natural Gas Hydrate Systems

Shubhangi Gupta

Gas hydrates are among the largest marine carbon reservoirs on Earth. The conventional view holds that, in the absence of external triggers, hydrate systems relax towards a unique steady state over geological time, characterized by fixed gas hydrate and free‑gas saturations. However, by employing a high‑fidelity multiphysics model that consistently resolves phase states across multiple fluid–fluid and fluid–solid boundaries, we show that hydrate systems can self‑organize into both fixed steady states and well‑defined periodic steady states embedded in the long‑term dynamics. These periodic states correspond to cyclic formation and dissolution of thick hydrate layers, producing internally driven, self‑sustaining oscillations over a broad range of natural marine settings. The coexistence of multiple attractors, both stationary and time‑periodic, implies that gas hydrate systems are not constrained to a single steady‑state solution for a given set of boundary conditions and parameters. Instead, small variations in key controls, such as burial rate, permeability, and hydrate kinetics, can shift the system between regimes with no hydrate, self‑organized fixed hydrate layers, and self‑sustaining cyclic rebuilding of hydrate and free‑gas reservoirs. Periodic states can manifest as spontaneous gas migration and pressure release in apparently unperturbed systems, with near‑instantaneous pressure drops of several bars on geological time scales, potentially promoting slope instabilities, fracture formation, and focused fluid escape features. Moreover, both the multiplicity of self‑organized steady states and the existence of time‑periodic states introduce an irreducible, yet quantifiable, dynamical uncertainty in hydrate saturation, free‑gas content, and gas release timing. This built‑in uncertainty adds substantial error bars to present‑day global gas hydrate inventory estimates and complicates predictions of hydrate responses to ongoing and future climate forcing.

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