Heat transfer in salt caverns

Several aspects of the thermodynamic behavior of salt caverns containing brine, oil, natural gas, air or hydrogen are discussed. It is shown that natural convection always appears in a liquid-filled cavern. This is not true in the case of gas caverns. Gas type, brine temperature at the cavern bottom and water vapor content are influential. Equations are obtained for the thermodynamic behavior of the fluids stored in a cavern during injection-withdrawal. Thermal evolution of a liquid-filled cavern at rest is slow; rapid injection and withdrawal are adiabatic and lead to small temperature changes. Heat capacity is much smaller in a gas cavern, temperature evolutions are much faster, and heat transfer from the rock mass must be taken into account. Evolutions can be described through a relatively simple equation. A simple model describing pressure and temperature in the wellbore during gas withdrawal is obtained.