Statoil is considering using an unmanned wellhead platform - instead of a subsea development - for a planned extension of the Oseberg field development.
 |
|
Illustration of unmanned wellhead platform. From Statoil. |
Oseberg, which is in Blocks 30/6 and 30/9 in the Norwegian North Sea, about 130km northwest of Bergen, first came on stream in 1988 from a manned field center complex.
Now, operator Statoil is planning a new platform without living quarters, helicopter deck or lifeboats. The concept is new to Norway, but has been used elsewhere in the North Sea. The jacket-based unmanned wellhead platform will reduce costs by several hundred million dollars, opposed to the alternative of placing the wells on the seabed, tripling the cost, says Statoil.
Statoil says it and its partners want to use service vessels connected to the wellhead platform by gangways during maintenance campaigns after the jackup drilling platform has completed its well drilling operations. All facilities will be found on the support vessel, with shorter distance to for example lifeboats and helicopter deck than on big installations. An investment decision is expected by next winter.
“The platform will have high-quality equipment to reduce the need for maintenance during the operations phase. Consequently we are planning for only two short maintenance campaigns per year, which will be carefully planned and performed in good-weather seasons,” says Ivar Aasheim, Statoil senior VP of field development. “Based on prognoses the costs of subsea systems are still rising. We challenge the industry to cooperate with us so we can turn this trend and develop smart solutions, both above and below water.”
Pre-studies of the unmanned wellhead platform are underway.
In June 2014, Statoil’s Anders Opedal, senior VP project management and control, discussed having an unmanned dry tree wellhead platform at the Underwater Technology Conference in Bergen, as an alternative to subsea developments. In August, Statoil awarded Kvaerner a concept study related to Oseberg.
Kvaerner’s “Subsea on a stick” concept focuses on minimization of facilities, equipment and costs in water depths of up to 150m. The new wellhead platforms could both increase recovery, use new generation jackups and reduce development costs.
The Oseberg field
 |
|
The Oseberg field. From Statoil. |
Oseberg field center’s three platforms, Oseberg A, B and D, are connected to one another with bridges in the southern part of the Oseberg field. The Oseberg C platform lies 14km north of the field center.
Oseberg A is a concrete base platform with process equipment and living quarters. Oseberg B sits above a steel jacket and has drilling, production and injection equipment. Oseberg D is a steel platform with gas processing and export equipment. It was connected to the field center with a bridge in 1999.
Oseberg C is an integrated drilling, accommodation and production platform with a steel jacket.
Gas export began from the Oseberg field center on 1 October 2000.
Read more:
Subscribe
