Ross was discovered in 1981 with the 13/29-1 well. Ten exploration and appraisal wells were drilled in and around the field and five of these tested oil. The field produces from two upper Jurassic reservoir zones.The Ross oil field is developed using a FPSO vessel, the Bleo Holm. Shuttle tankers are used to export the oil to market. Associated gas was shipped via the Frigg UK pipeline to the Frigg St. Fergus terminal. The drilling program includes approximately 10 high angle or horizontal wells from three sites in order to optimise reserves recovery. Currently the field produces from 6 wells and a further 5 wells are used for injection. Two drilling contracts were awarded to Global Marine Drilling Company and Transocean Offshore (North Sea) Limited respectively. The Glomar Arctic III drilled the first two development wells and the Transocean Discoverer rig drilled further eight wells. Talisman and the Ross co-venturers are committed to minimising the impact of this development on the environment. Rather than flare the relatively low volumes of associated gas, the gas will be evacuated via a 23 km long pipeline to the Frigg UK System. Well fluids from the Ross and Blake fields arrive on the Bleo Holm through subsea manifolds, flowlines and risers, then the turret piping and swivel. They are then routed to the crude separation area with Ross fluids to the former test separator and Blake fluids to the production separator. Wet oil from the first stage separators is passed to the second stage separator together with recovered condensate and oil reject oil from the produced water hydroclones. The combination of temperature and pressure in the second stage separator ensures that the hydrocarbon liquids are stabilised to a low Reid Vapour Pressure (RVP) suitable for storage and shipment. The crude oil from this separator is then pumped to the desalter vessel before transfer to the storage tanks.Produced water from the three separators is treated to reduce the oil-in water content before discharge overboard.Gas produced in the second stage separator is passed to the LP compression train where it is raised to the pressure of the production separator. Gas from the production and test separators is cooled and fed to the 3-stage HP compression train. Before the inlet to the third stage, the gas is dehydrated by glycol contacting. Gas form the HP compressors is used for fuel (2nd stage discharge), lift, with any excess exported by pipeline.
Ross, North Sea, Encana, Europe(North),