The Ross Field
The Ross field (RockRose – 30.82%) lies approximately 110km NE of Aberdeen. It has been on production since 1999, producing undersaturated oil from variable quality, relatively thin Ross sands of Upper Jurassic age at a depth from 2700 to 3200 m ss, and also from the underlying Parry sand, Reservoir performance is influenced by faulting, which causes compartmentalisation.
The Ross sand has been developed by six horizontal gas lifted production wells and four water injectors. The oil is produced into a leased FPSO where it is processed and then exported via shuttle tanker. Gas not used as fuel is exported by pipeline via the Frigg transportation system. The field has been developed through (several) cycles of infill drilling following the initial development of the field. A total of six horizontal gas lifted production wells and five water injectors have been drilled, of which three of the gas lifted production wells and no water injectors were in use in 2017. The oil production rate peaked briefly at around 39 Mstb/d oil in 199. The field is now at a mature stage of production, producing some 0.8 Mstb/d oil and 1.5 Mbbl/d water, a water cut of some 65%. The cumulative oil production as at 20/09/2017 is 33 MMstb.
The field has experienced downtime throughout 2016 and 2017 due to, amongst others, high oil in water levels, high H2S levels and gas lift problems. Wells RP2 and RP3 have both suffered from gas lift unavailability: gas lift mandrels could not be opened due to high wellbore pressure. At the time of wiring this report, high wellbore pressure is still reported in Well RP3. The well is expected to progressively de-pressure until Q1 2018, when full potential is expected to be reinstated. Well RP2 is also currently shut in due to a leak in the hydraulic line, but is expected to be reinstated in Q2 2018. Well RP2 is currently producing.
There is no cost share with the Blake field, and instead the Ross field pays a tariff. With respect to cost allocation all Bleo-Holm upgrade and repair costs are therefore borne by the Blake field. With respect to the field specific costs (OPEX), ERC Equipoise has accepted the operator’s forecast for 2018, and maintained our historical assumptions. These costs include subsea inspections carried out in alternating years.