Underground · Storage
Salt Cavern Storage
Large cavities washed out of an underground salt layer by circulating water, then used to store NGLs, crude or natural gas.
What it does
Salt is tight and self sealing, so the cavern holds product safely at depth. Liquids are pushed out by injecting brine, which is kept in a brine pond at surface. For gas, caverns need little base gas and can cycle several times a year at high rates. Fort Saskatchewan, near Edmonton, stores NGLs such as propane and butane this way.
Basics
| Made by | Solution mining with water, brine to surface |
| Stores | NGLs, crude, natural gas |
| Product out | Displaced with brine for liquids |
| Gas service | Little base gas, high deliverability |
Common failures
- Leak through the well casing or cement, the weak point of a cavern
Troubleshooting
- Symptom
- Cavern pressure falls with no withdrawal
- Likely cause
- Leak at the well or loss to the formation
- What to check
- Run a mechanical integrity test of the well and cavern