Many oil and gas production sites, especially those not connected to a pipeline, have numerous tanks for the storage of produced hydrocarbons, as well as fluids used in the drilling, stimulation, and enhanced recovery stages of operations.
Although the majority of natural gas is separated from the oil by production equipment, the oil will continue to outgas once it’s stored in tanks. Since a tank is a confined space, it should always be assumed that gas is present in the tank. Gas can cause explosions and asphyxiation – not things with which to mess around.
Luckily, by following a few simple guidelines, it’s possible to reduce the risks to a manageable level.
Rules for tank safety:
- Tanks should be kept at a very slight positive pressure. This prevents oxygen, required for combustion and explosions from entering the tank.
- Workers working on an open tank, or sounding the tank (tapping it with an object) to determine its level, should wear grounding straps, which prevent the buildup of static electricity, which could cause an explosion
- Never enter a tank unless the tank is empty and entry by properly-trained and equipped personnel is approved by a manager.
To prevent corrosion of the bottom of a metal tank from moisture and oxidation, it should be elevated above the ground so it is more likely to stay dry.
Lastly, tanks should be regularly pressure tested to assure integrity and checked and treated for rust development.
Images: “Hazardous Safety” by Michael Black