Det norske hits oil with Ivar Aasen appraisal wells
STAVANGER, Norway -- Det norske oljeselskap AS, operator of production licence 001 B, has completed the drilling of appraisal wells 16/1-21 S and 16/1-21 A on Ivar Aasen field, the Norwegian Petroleum Directorate reports.
The field is located in the central part of the North Sea and was proven in 2008. The size of the field prior to the drilling of these two appraisal wells was 24 million standard cubic meters (Sm3) of recoverable oil, 1 million Sm3 of recoverable condensate and 4.5 billion Sm3 of recoverable gas.
The primary target for wells 16/1-21 S and 16/1-21 A was to investigate reservoir rocks and reservoir quality, as well as the extent of an overlying gas cap in the eastern part of the field in Middle Jurassic to upper Triassic reservoir rocks (the Hugin, Sleipner and Skagerrak formations, as well as the Statfjord group). In addition, 16/1-21 S had a secondary exploration target in overlying Paleocene reservoir rocks (the Heimdal formation).
16/1-21 S encountered a total oil column of 54 m, of which 25 m were of good to very good reservoir quality in the Skagerrak formation. The oil is undersaturated, which is also the case in the eastern part of the field (16/1-16 and 16/1-16 A). The gas/oil ratio (GOR) in the oil zone is 130-145 Sm3/Sm3. The oil/water contact was not encountered, but was calculated at approximately 2,436 m, which is 2 m deeper than previously assumed in the Skagerrak formation. Gas was not encountered in the well. In the Heimdal formation, the well encountered 27 m of aquiferous sandstone of good to very good quality.
16/1-21 A encountered a total oil column of 41 m and a 4-m gas column, of which a total of 29 m was of very good reservoir quality in the Sleipner and Skagerrak formations. The oil in the Sleipner formation is saturated, while the oil in the Skagerrak formation is largely undersaturated. The oil/water contact was not encountered.
The well results have yielded valuable information as regards the final location of production and injection wells. Further work going forward will integrate the new data and contribute to increased field understanding.
Ivar Aasen field consists of production licences 001 B, 028 B, 242, 338 BS and 457. The Plan for Development and Operation (PDO) was submitted to Norway's Ministry of Petroleum and Energy on Dec. 21, 2012.
Extensive data acquisition and sampling have been carried out. These are the fourth and fifth appraisal wells in production licence 001 B. This production licence was carved out of production licence 001 on Dec. 15, 1999. PL001 was originally awarded on Sept. 1, 1965 (round 1-A).
Wells 16/1-21 S and 16/1-21 A were drilled to measured depths of 2,630 m and 3,313 m, respectively, and vertical depths of 2,530 m and 2,463 m below the sea surface. Both were terminated in the Skagerrak formation in the Upper Triassic. The wells have been permanently plugged and abandoned. Water depth at the site is 113 m.
The wells were drilled by the Maersk Interceptor drilling facility, which will now continue drilling appraisal well 16/1-22 S in the western part of Ivar Aasen field.
