Norsk Hydro Submits Amended PDO for Oseberg Sør

On March 1st the authorities received an application from Norsk Hydro regarding approval of an amended Plan for Development and Operation for part of the development on Oseberg Sør. The amendment concerns development of the oil discovery in the J structure which is situated in the southern part of the field.

Hydro originally planned a 8-9 km two-branch production well from the Oseberg Sør installation in order to produce this discovery. In the amended plan, the oil will be produced from wells drilled from a subsea template.

Even if it is now possible to drill very long wells, the NPD has pointed out that in some such cases more flexibility and a better exploitation of resources will be obtained by drilling from subsea installations, as is now the plan for the J structure.

The original PDO for Oseberg Sør was approved by the Storting (Norwegian Parliament) in 1997, and following the development period the oil production from the Oseberg Sør installation started in 2000.

In addition to the Oseberg Sør installation, where the oil is transported onwards to the Oseberg field centre, the original development plan also covered two subsea installations, one above the K structure and one above the J structure.

Both of these were to be connected to the Oseberg Sør installation through pipelines. The K structure and the J structure contain oil that is situated a little way south of the rest of the field. The amended plan which is now being submitted for approval concerns the J structure. In the original plan for the J structure, only water injection had been planned from the subsea installation. Wells for oil production, which were intended as an 8-9000 meter long well with two branches, were to be drilled from the Oseberg Sør installation. In the revised plan, both injection wells and production wells will be drilled from the subsea template.

As a result the production wells will not be as long, and there will be greater flexibility if there is a need to alter the drilling plans on account of new reservoir information. To start with the plan is to recover 3.8 mill Sm3 oil and 0.5 billion Sm3 gas from the J structure, with production start-up in 2004.

Together with the other licensees, Norsk Hydro is also working on specific development plans for several of the discoveries in the Oseberg - Oseberg Sør area. Various development plans for long platform wells or subsea installations are being considered.

The NPD has pointed out that in some such cases, a greater flexibility and a better exploitation of resources will be obtained by drilling from subsea installations as is now planned for the J structure. Through the sale of SDFI interests in 2001 and 2002 an even distribution of ownership interests in these fields have been obtained among the various licensees in Oseberg, Oseberg Sør and Oseberg Øst. The license interests for these fields are now distributed as follows: Norsk Hydro Produksjon as (operator) with 34.0%; Petoro AS with 33.6%; Statoil ASA with 15.3%; TotalFinaElf Exploration Norge AS with 10.0%; Mobil Development Norway AS with 4.7%; and Norske Conoco A/S with the remaining 2.4%.

Since all the companies now have an even interest distribution across these fields, conditions should favor the best possible exploitation of the infrastructure that has already been developed in the area.