Subsea water treatment module to improve oil recovery

NOV just completed a joint industry project with the aim to verify and demonstrate installation – and performance aspects of a full-scale Seabox™ subsea water treatment module in a realistic subsea environment. The Seabox module was installed close to Stavanger, Norway, at 220-meter water depth. Seawater was drawn through the module and a 540-meter-long pipe by use of a submerged pump. To verify the performance of the Seabox treated water, samples of the treated seawater were compared with raw seawater samples collected from the same seabed location.

The Seabox module has shown great results after a three-month duration of testing. Not only were the three parts of the Seabox module successfully installed, the treatment unit has been retrieved and the comparison samples show solids removal and disinfection capabilities beyond expectations. In that specific seafloor environment, the Seabox module removed on average 60% of all particles and 99.9% of all particles above 8.5µm. Tested according to oil industry practice, results demonstrate complete bacteria kill. There were also no SRBs or GRBs below detectable limits.

The Seabox subsea water treatment module showed a stable performance with 100% regularity throughout the test period, providing treated water with a stable solids removal and disinfection despite variations in the raw seawater quality. This verification of the performance of the Seabox module demonstrates the ability to serve a variety of duties for water injection – e.g. as pre-treatment to filtration and membrane technology or as a standalone solution.


Smart water injection solution for reduced cost and added value

The Seabox system enables water treatment to be done directly at the seabed and water to be pumped straight into the injection well. This will allow the operator to optimize waterflooding and improve oil recovery. Two successful pilot projects, backed by the Norwegian Research Council and several major oil companies, have demonstrated that the Seabox system reduces water treatment costs compared to other types of systems.

Water injection is the most common way to increase oil production, but traditionally, this has required expensive and bulky topside equipment. With the Seabox™ subsea water treatment unit and SWIT™ Technology, the water treatment is done directly at the seabed and the treated water is pumped straight into the injection well. The SWIT Technology provides the right quality water for water injection where it is needed, when it is needed. This fully flexible approach allows operators to optimize water flooding with the right quality water at any time and location to improve recovery.

Seabox subsea water treatment unit and SWIT Technology is a subsea technology, developed during the last 10 years with support and sponsorship from major oil companies. The technology enables treatment of raw seawater directly on the seabed to the desired quality for injection into oil wells for pressure support, sweep and increased oil recovery. The development started in 2003 and embarked on a series of Joint Industry Projects (JIP) backed by the Norwegian Research Council and major oil companies. Through these projects, the Seabox unit and SWIT Technology have been developed and are now ready for real applications.

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