Well Processing - Subsea Water Injection and Treatment (SWIT) for Increased Oil Recovery

Well Processing, a Norwegian subsea technology company, provides engineering solutions for subsea processing, including its unique subsea water injection and treatment (SWIT) technology.

Subsea water injection and treatment (SWIT)

SWIT is a breakthrough in water treatment for subsea processing that enables:

• Increased oil recovery and enhanced oil production
• Significantly reduced CAPEX and OPEX

SWIT can be utilized for all oil fields where seawater is used for pressure maintenance and drive mechanism. Well Processing can perform engineering studies and investigate how SWIT may benefit your specific application. It has a resource base of more than 800 engineers and specialists with a blend of topsides processing and subsea expertise.

Increased oil recovery seabed treatment

Injection of seawater into an oil reservoir is a recognized method of increasing the recoverable volume of oil in place and enhances production. Traditional methods for treatment of seawater come at a price: heavy and expensive treatment plants that are costly and operator intensive to run. Injection volumes are limited by several factors and require valuable topside well slots that should preferably be used for production.

The SWIT technology overcomes these restrictions by placing equipment on the seabed and is suitable for both new and mature fields. The SWIT treatment principles are proven at laboratory scale and an industry-sponsored pilot will be demonstrating the technology in the field.

Flexible subsea water and injection treatment

SWIT gives reservoir engineers the flexibility to inject as much treated seawater as desired into areas of the reservoir that will benefit the most. Engineering studies have shown that SWIT may reduce CAPEX by up to 50%.

SWIT can be run continuously for up to two years without any sort of intervention and a reduction of more than 25% OPEX is usually expected.

Solid removal

Inorganic particles down to 10µm can be removed from the raw seawater. A patented stillroom concept is the key element in the removal process. The removal process does not use any filters, which eliminates clog up, and there is no required maintenance for a continued operation of up to two years.

Seawater sterilization

The raw seawater is sterilized in a two-stage process. The first stage comprises electrical generated hypochlorite, including a long exposure time, which enables the chlorine to work properly. The second stage comprises a new and patented technology utilizing electro-chemically generated hydroxyl radicals for sterilization.

Hydroxyl radicals work instantly , are 2.5 times more bactericidal and fungicidal than chlorine and have proven extremely effective for this sterilization process. The whole sterilization process is designed for a minimum of two years’ continuous operation without intervention.

SWIT system sterilization

The SWIT system also provides for a periodic shock dosing with biocide similar to conventional topside systems. However, due to superior sterilization, the biocide requirements are reduced and the dosing intervals may be extended significantly. The replenishing of chemicals is every two years and is handled in sealed containers with no exposure to personnel.

Seabed injection

The treated seawater can be injected directly into the reservoir by a subsea injection pump or transferred to a topside platform or an onshore facility, depending on requirements and the configuration of the complete system.

Subsea seawater treatment

SWIT has the following benefits:

• Provides as much water as required at the location where it is required
• Provides purer and better quality water than traditional systems; for offshore fields, no seabed pipelines or long deviated wells are required
• An easy-to-install all electric solution with flexibility in power and signal supply
• Reduces environmental impact due to less chemical usage and significantly lower power requirements