Natural-gas hydrates can form and are stable under specific ranges of elevated gas pressure and temperature, conditions that depend largely on gas composition and hydrate structure. When pressures (P) and temperatures (T) are changed, placing these hydrates outside their stability field, they are prone to decompose at rates that depend on many factors, including hydrate composition and structure, the degree to which the equilibrium boundaries defining the stability field are exceeded, the P-T-time pathway taken to make them unstable, and the physical state and properties of the hydrate and its surroundings.