Field extension

A number of options were considered for extending the production life of the Magnus field, which has been producing oil and gas from platform and subsea wells for 20 years. First component of the overall Magnus Exploitation Project is the Swift (subsea water injection facilities & tieback) project.

The Swift Project

• Tying subsea water injection wells back to the Magnus platform by means of a 'mini' manifold for up to seven water injection wells, a subsea flowline and umbilical.
• The function of the manifold is to distribute injection water from a single flowline to seven cluster wells and to link these wells for control purposes to the Magnus platform by way of a subsea umbilical.
• The flow capacity of the system is 160,000 barrels per day.
• Individual well capacity is 40,000 barrels per day

The Magnus Enhanced Oil Recovery Project

This project involved the construction of a subsea pipeline system to carry gas from the producing fields west of Shetland (Foinaven, Schiehallion and Loyal), to the Magnus platform in the northern North Sea, via the Sullom Voe Terminal (SVT) in the Shetland Islands. The Project was sanctioned in 2000 and brought on-line in 2002.

The important environmental benefits from the project include:

• Beneficial use of excess gas from the Foinaven and Schiehallion fields, which was previously injected into gas disposal wells.
• More efficient hydrocarbon production at Magnus (via tertiary recovery).
• Reduction in atmospheric emission from power generation by making natural gas available to both SVT and the market.

The gas is injected into water injectors using a water-alternating-gas (WAG) scheme. This allows for the gas to effectively capture oil that is not recovered by water injection as the secondary recovery mechanism

Magnus Infill Drilling

Magnus recommenced drilling operations in 4Q08 to further extend the economic operating life of the Magnus Field.  Continuous drilling operations (save for planned maintenance outages) are anticipated through to 2013, with a review of additional opportunities beyond that.