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Subsea Storage Unit on sea floor

Subsea Oil Storage System

We enable emission reduction and flexible storage of oils and condensates

  • Description Description
  • Ruler Specifications

Our Subsea Oil Storage system can be used to replace floating storage and offloading 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. This helps reduce or even eliminate conventional, polluting or potentially hazardous, storage solutions and is rapidly emerging as the most environmentally friendly method for oil storage.

We can provide a full system solution, including a process system and offloading. The subsea storage solution can be combined with a jack-up based field proven mobile offshore production unit (MOPU) platform.

Our engineering and testing activities have proven that it’s possible to operate a subsea storage unit with a flexible membrane that defines the horizontal interface between oil and seawater. This membrane eliminates the problems with emulsion-layer build-up and bacteria growth found between oil and seawater in the initial storage solutions.


  • Low CO2 emission: NOV storage solution will save 140,000 Tonnes of CO2 compared to a FSO over 10 years.
  • Easy to design for decommissioning and redeployment: Standard and reusable design.
  • Capital expenditure (CAPEX) savings and low operating expenditure (OPEX) compared to FSO’s.

Our Subsea Oil Storage system provides modular storage of oil or condensates. The system consists of a cluster frame with storage units, power, control and monitoring, fluid transfer system, export riser and offloading system. The subsea storage unit (SSU) consists of a protective structure and membrane. The seawater outside the protection structure surrounds the membrane 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 solution is not dependent on offloading frequency and can be customized to fit field requirements. From a design and construction perspective, SSU’s are an elegantly simple, high-tech answer to the question of how to store oil offshore. The system is designed with continuous level monitoring and leakage detection.

Value Proposition


Elimination of emulsion layer.

Emulsions is a bacteria growth layer that between the oil and water contact. This will be avoided, as the oil is stored in a membrane, which is protected inside a protective structure. The NOV solution can make the system up to 30 % smaller. An emulsion layer can be several meters tall and requires special handling to be removed.

Low environmental impact with larger volumes subsea

NOV storage solution will save 140,000 Te CO2 compared to a FSO over 10 years. Reduced environmental fees.

Reduce topside HSE challenges

Reduced offshore manning. No need for classification of vessel, supply vessel (food, spare parts, suppliers, etc.) and/or standby vessel.

Easy to design for decommissioning and redeployment

Storage solution that can be placed at any location and water depth. Easier to target the required storage capacity needed, flexible and scalable during the field lifetime.

No need for dual loading systems like STL/SDS

Robust subsea storage in stable environmental conditions, not affected by extreme weather conditions

Subsea storage of oil and condensates. Double barrier against leakage to the sea.

NOV Offshore Production promo graphic

NOV's Offshore Production Solutions leverage our recognized and long-standing proficiency, experience, and diverse process and production systems. Uniting economical design, superior technologies, and integrated systems, we enable our clients to optimize upstream operations and unlock full field potential.

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