The first subsea gas compression plant in the world goes on line; step change in subsea technology
19 September 2015
Statoil and its partners this week put the first subsea gas compression facility on line at Åsgard in the Norwegian Sea. Subsea compression will add some 306 million barrels of oil equivalent to total output over the field’s life, the partners said. This subsea technology milestone opens new opportunities in deeper waters, and in areas far from shore.
This is one of the most demanding technology projects aimed at improving oil recovery. We are very proud today that we together with our partners and suppliers have realized this project that we started ten years ago. Subsea gas compression is the technology for the future, taking us a big step closer to our ambition of realising a subsea processing plant, referred to as the subsea factory.—Margareth Øvrum, executive vice president for Technology, Drilling and Projects
Recovery from the Midgard reservoir on Åsgard will increase from 67% to 87%, and from 59% to 84% from the Mikkel reservoir.
As a field gets older, the natural pressure in the reservoir drops. In order to recover more oil and gas, and move this to the platform, compression is required. The closer to the well compression takes place, the more oil and gas can be recovered.
Traditionally compression plants are installed on platforms or onshore, but this plant is located in 300 meters (984 feet) of water. Prior to gas compression, gas and liquids are separated out, and after pressure boosting recombined and sent through a pipeline some 40 kilometers (25 miles) to Åsgard B. The project started in 2005, and the plan for development and operation (PDO) was approved in 2012.
An estimated eleven million man-hours have been spent from the start until completion. More than 40 new technologies have been developed and employed after prior testing and verification. Some of this work has taken place at Statoil’s Kårstø laboratory in Western Norway.
Overall, project cost were just above NOK 19 billion (US$2.4 billion).
In addition to improving recovery subsea gas compression will be more energy efficient than the traditional topside solution. The technology reduces significantly energy consumption and CO2 emissions over the field’s life.
Today almost 50% of Statoil’s production is recovered through some 500 subsea wells. Statoil’s subsea expertise is essential to successful production efficiency improvement and increased oil recovery efforts.