Salt Cavities

Natural gas and air has been stored successfully in solution-mined salt cavities because of the impermeability of the salt. Salt is an attractive medium because it functions as a self-healing material. The process of solution mining causes the salt to re-crystallize along the cavity walls creating an essentially impermeable surface. The crystallized salt membrane, the exceptionally low matrix permeability, and the plastic nature of salt enable it to seal secondary fractures in the rock to create a nearly ideal gas storage vessel.

The solution mining of salt process typically form elongated irregular shaped cavities within the salt bed or salt diaper structure. The solution mining of salt involves the injection of water through a well into the salt bed or dome structure. The dissolved salt in the water solution is then extracted through the annulus of the water injection well for disposal at the surface. Factors that impact the development and use of solution mined salt cavities are:

  • Limits on the physical size the cavity,
  • Removal of non-soluble impurities in the salt formation,
  • Disposal of the solution mined salt, and
  • Potential collapse of the cavity because of plasticity of salt.

Since 2005, Hydrodynamics has conducted 3 CAES studies in salt formations. We evaluated a major salt dome in Ireland for CAES development. The evaluation was complicated by the presence of volume rock within the salt dome. We also evaluated the potential of salt beds in the Texas Panhandle and West Texas. The studies involved both the evaluation of available salt core samples, and the evaluation of well log data.