In September 2015, Equinor put the world’s first subsea gas compression facility into operation at the Åsgard offshore gas field on the floor of the Norwegian Sea. It features two 11.5-MW subsea high-speed, oil-free integrated motor (HOFIM) compressor units from MAN Energy Solutions (MAN). Five years later, the subsea compression facility has achieved 80,000 operational hours with an availability of close to 100% at a depth of 984 ft. (300 m).
“We are very proud that our subsea gas compression facility has reached five years of successful operation,” said Randi Elisabeth Hugdahl, vice president of Åsgard operations at Equinor. “The pioneering subsea technology we implemented at Åsgard represents a quantum leap for the global energy industry. Putting the compression system on the seabed near the wellheads improves recovery rates and reduces capital and operating costs. Moreover, it has essential advantages in the form of improved safety for our employees and a significant reduction of the carbon footprint. At the core of the subsea technology lie two MAN HOFIM compressor systems, which have been operated at full load since start-up in 2015. Their overall performance throughout the five years of operation has exceeded our expectations.”
In 2015, analyses indicated that the pressure in Åsgard’s reservoirs would eventually be too low to ensure stable flow and satisfactory production. The need for compression resulted in the installation of two HOFIM compressor units, operating with a design pressure of 3190 psi (220 bar). Gas flows from the Statoil-operated Åsgard reservoir to the Åsgard B processing platform, 25 miles (40 km) away.
According to Equinor, the subsea technology has extended the reservoirs’ productive life another 15 years and will add around 306 million barrels of oil equivalent during this period.
“Together with Equinor and our subsea compression alliance partner, Aker Solutions, we started a whole new chapter for the oil and gas industry five years ago. Our innovative, subsea technology makes offshore gas-recovery more sustainable and efficient,” said Basil Zweifel, vice president sales and execution, upstream and midstream, at MAN. “On top of that, our highly digitized, compressor system can be remotely operated, which makes it the ideal technology solution for topside applications where unmanned operation is required.”