In February 2021, Aker BP completed its first subsea well completion operation using ROCS on the Ærfugl Field development, a subsea tieback to the Skarv infrastructure in the Norwegian Sea. It has since successfully run the ROCS on six more wells without any downtime.
“Our own analyses show significant benefits of applying the ROCS instead of a traditional system when completing subsea wells," said Mads Rødsjø, Aker BP's vice president of D&W Operations. “We have reduced our operating time, hence reducing the weather window requirement; we see less HSE exposure on the drill floor; have lowered our CO2 footprint; and through digitalization, we have removed 45 tons of surface equipment.”
Optime will supply the two new, second-generation ROCS over a period of three years. They will feature a new standalone communication system designed to support rig flexibility and more efficient operations.
In addition, the company will provide its new universal landing string system Panpipe, which can be sheared and sealed throughout its length.
Earlier this year Optime committed to construct 10 similar ROCS systems, based on interest from operators globally.
The ROCS is designed to eliminate the need for a heavy umbilical running from the topside to the seabed to control the tubing hanger during completions of subsea wells. It also avoids the HSE risk associated with deploying a large topside hydraulic unit.
When completing subsea wells, the tubing hanger is placed on top of the wellhead, as a seal toward the rest of the subsea well.
Normally the tubing hanger is controlled through a dedicated hydraulic umbilical with a 20-ft to 30-ft control container. When running the umbilical, it is also clamped to the tubing for increased stability.
ROCS replaces these operations by remotely controlling a controls unit toward the wellhead. The system is mobilized in a single basket, prepared and made up onshore, so it can be run immediately when offshore from a rig.