Four Subsea Oil Storage units underwater

Subsea Oil Storage

Our subsea storage system is designed to store hydrocarbons with or without dissolved gas at ambient pressure.

  • Description Description

The subsea oil storage system provides modular storage of oil or condensates and consists of a protective structure and membrane on the seabed. It can be used to replace floating storage units (FSO/FSU), other subsea storage solutions, or an export pipeline. The modular design can be customized to fit the project need, such as for marginal field development. 

We can provide a full system solution, including a process system and offloading.

From a design and construction perspective, subsea storage units (SSUs) are an elegantly simple, high-tech answer to the question of how to store oil offshore. An SSU consists of a structure that employs the concept of a flexible bag protected by a dome for storage on the seafloor and thereby eliminates problems with emulsion layer and bacteria growth. It can be placed at any water depth and is adjustable in size depending on the needs during the development and expansion of the field.

The seawater outside the protection structure surrounds the flexible bag through free-flow seawater openings in the protecting structure such that the hydrostatic pressure acts directly on the stored fluid; hence, the internal pressure is equal to the external seawater pressure. The oil is stored at a hydrostatic pressure greater than the oil vapor pressure, preventing gas separation. The partially stabilized oil is offloaded to a shuttle tanker with capabilities of handling such a vapor pressure (liquified petroleum gas). The solution is not dependent on offloading frequency and can be customized to fit field requirements.


  • Standard and reusable design
  • Easy to design for decommissioning and redeployment
  • Technically competitive solution
  • Capital expenditure (CAPEX) savings
  • Low operating expenditure (OPEX) compared to floating storage offloading (FSO) units
  • Unmanned storage solution
  • Low CO2 emission
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