A classification of storage tanks

Various types of oil storage tanks and their components

There are many methods to classify reservoirs. However, as there is no general rule for this purpose, the general classification is performed using standards and rules based on pressure. In this regard, the tanks employed in the industry are described as follows :

• Process tanks

• Low-pressure storage tanks (LP-tank)

• Non-pressure storage tanks (NP-tank)

• High-pressure storage tanks (LPG sphere tank, LPG bullet tank)

• Cryogenic Compressed gas tanks. （LNG/LPG/Ethylene/Ethane/Propane/Ammonia tanks）

Here, a question arises where are the oil reserves in this reservoir classification? Since the pressure applied to these reservoirs is only hydrostatic pressure because of oil fluids, these reservoirs are considered the types of LP-tank or NP-tank. According to the API 650 standard, the pressure of these reservoirs is less than 2.5 psi, which is an insignificant amount.