Subsea production is moving into increasingly deeper waters with longer step-outs and more complex seabed systems. Ifokus Engineering is targeting the potential of electric control and power systems, which could offer cost-effective, time-saving and flexible solutions.
The company specializes in designing and building equipment for the remote operation of subsea production and transportation systems. Since its formation in 2000, it has developed tools and equipment for fluid transfer and control, valve intervention and ROV tooling.
Over the past five years, Ifokus has developed a range of subsea electric fail-close actuators and recently delivered its first “permanent” installation, supplying three actuators to Total’s Dalia field development in 1,400 m (4,593 ft) water depth offshore Angola. These items have been retrofitted to the ROV override on a chemical injection valve, taking over the function from hydraulic actuators which were defective.
According to sales manager Helge Eide, operation of the electric actuators involves the use of a patented power bank in which 24 V of power is accumulated via two twisted pairs from the communication line at 1 amp - therefore there is no need for a dedicated power supply from the surface. Full charge-up can be reached in less than 30 minutes, and each actuator can be operated every 10 minutes.
The company first developed this solution for use on ballast control valves on the Atlantis artificial seabed project, but had to refine and qualify the design for the Dalia application as it involves hydrocarbons.
Compression pilot
Ifokus also has designed electric actuators for Norsk Hydro’s Ormen Lange pilot subsea compression project - its involvement here going back three years. Early this year, Ifokus was developing specifications for actuators for the complete system under a contract from the pilot system contractor, Aker Kvaerner Subsea. The company will now build and qualify the actuators for the pilot system.
Hydro had various reasons for specifying electric actuators for this project, according to Ingebret Søyland, Ifokus’ project manager for electric actuators. The main one was instantaneous response time. They also are more reliable, do not require the installation of a hydraulic power unit on the seabed, and do not involve any emissions into the marine environment, as can occur with hydraulic systems. In the case of a long step-out like Ormen Lange (123 km, or 76 mi), they also avoid the problems associated with lengthy hydraulic umbilicals. A special concern is the anti-surge valve which, like any fail-safe valve, must be totally reliable. By opening a bypass loop, this valve protects the compressor when incoming flow pressure exceeds a critical level. To achieve the required stroking time of less than two seconds, a very high actuation force is required. This is another case in which an electric actuator has an advantage over a pneumatic system. A pneumatic actuator would have to be huge to deliver the required force, Søyland says.
Assuming the challenges can be overcome, a rich potential prize may await in the shape of the many subsea projects which would benefit from subsea compression. Statoil, for example, is planning to use similar technology on the Åsgard field in the Norwegian Sea, and eventually on Snøhvit in the Barents Sea.
Single stab connections
Another new product, one Ifokus launched last year, is 3Stab, a multifunctional tool for hot-stabbing subsea tools and equipment. It is designed for any application involving power, communication and/or hydraulic fluids, which can be connected with a single stab - not possible previously, according to Eide.
3Stab, Ifokus’ multifunctional tool for hot-stabbing subsea tools and equipment.
A new, patented 3Stab inductive technology enables power transfer of close to 95%. The previously available inductive systems were less efficient, and also at times ran the risk of energy being converted into heat, causing control pod meltdown.
The 3Stab connection is faster and simpler than the standard MQC - multi quick connection. The male connector is installed on the subsea tool or skid and the female receptacle on the ROV. Thus, electrical, communication and hydraulic connection can be made and unmade subsea with one stab without returning to surface.
The first order for 3Stab is from a leading subsea contractor which plans to use it on an ROV-mounted pull-in and connection tool. Ifokus next aims to develop the tool for permanent installation, and is looking for a partner to participate in the project.
