Schoonebeek oil field: the RW-2E steam injection project

Abstract

The Dutch Schoonebeek oil field initially contained 170 x 106 m3 of 25° API crude. primary recovery is low mainly due to the high viscosity of the oil. It varies between 6% of stock tank oil initially in place (STOIIP) in the west (solution gasdrive) to 18% in the east (waterdrive). Research on enhanced recovery began in 1950 and concentrated on thermal processes. As a result hot water injection has been applied on a large scale increasing the recovery of oil by 8% of STOIIP. The performance of hot water injection projects is declining and a gradual switch is being made towards steam injection. Steam injection was applied already in 1960 in a depleted part of the field. In 1972 a pilot project was started to test the feasibility of steam injection in the much larger waterdrive part where pressures are kept at the hydrostatic level of 85 bar by aquifer water influx. This project indicated that steam injection under waterdrive conditions is a very effective recovery process and that a recovery increase of 14% of STOIIP can be obtained at an extra-oil/steam ratio exceeding 0.6 m3/ ton. On the basis of the pilot results a large scale project was designed, the RW-2E steam injection project. It consists of 14 steam injection wells,43 producers and 14 water disposal wells. Steam will be injected at a total rate of about 3000 tons/day for a period of 6 years. Additional oil recovery of the RW-2E,project is estimated at 4 x 106 m3. The maximum additional oil production rate is estimated at 1500 m3/day. During the design and construction of the RW-2E project extreme care was taken to minimise the impact of the project on the environment. The project started in January 1991. Total project life is estimated at 15 years.