That is one single well performing close to an entire oilfield. The outcome was a well that was tested at 78,000 b/d. To give an example: based on the seismic information acquired in 1998, we changed the location of a planned production well from west of the platform to more than 1km away to the north of the original target. Seismic surveys enable us to understand the reservoir dynamics and make even better decisions. The sixth seismic survey will be conducted in the summer of 2013, using PGS’ Atlantic Explorer. The next seismic will be broadband seismic, but still compatible with the previous seismic, such that 4D data still will be achieved. With the exception of one high resolution seismic acquisition in 2004, these have been conventional seismic acquisitions. The first seismic acquisition was made before production start-up and has since been repeated four times at regular intervals. We have continuously monitored the fluid movements in the Draugen reservoir by extensive use of seismic surveys. This approach raises the statistical recovery factor to 35-45%. By doing this, the reservoir pressure was maintained while also pushing the oil towards the middle of the field, where the platform is located. We installed water injectors at each end of a long and fairly narrow field. This key decision was already in Draugen’s Plan for Development and Operation (PDO), submitted in 1988. Our first step was to add pressure support. We therefore implemented an active reservoir management strategy. By natural underground pressure, the statistical recovery rate is expected to be only 5-15%. However, the good reservoir quality is not the only reason why Draugen has achieved such a high recovery rate. We are in the lead in Norway when it comes to extracting the maximum amount of oil out of a reservoir. The average recovery factor in Norway is 46%. Today the recovery is multiplied by four, now getting close to 70%. We assumed a recovery factor which seemed realistic at the time, in the late 1980s: about 17% of the oil would be produced. The producing formation had excellent characteristics. Oil from Haltenbanken had migrated eastwards and up, and Draugen was discovered at a shallower level than the other reservoirs in the area. Draugen was expected to reach end of field life in 2013, according to the initial plans, but we are currently in the process of extending Draugen’s lifetime till 2036.ĭraugen was discovered in 1984, in an area where most geologists did not bother looking for hydrocarbon-bearing reservoirs. In 2013, Draugen marks 20 years since the start of production. Draugen was the first field to be developed in the Norwegian Sea, pioneering production from an area which later became one of the important petroleum provinces in Norway.
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