Wintershall Completes North Sea Wildcat
Wintershall Norge AS, operator of production licence 457, has completed drilling of wildcat well 16/1-16 and appraisal well 16/1-16 A.
The 16/1-16 and 16/1-16 A wells were drilled about 1.8 miles (three kilometers) east of the 16/1-9 discovery well in the Ivar Aasen discovery and about 1.8 miles (three kilometers) north of the Edvard Grieg field in the central part of the North Sea.
The primary exploration target for the 16/1-16 wildcat well was to prove petroleum in Lower Cretaceous and Upper Jurassic reservoir rocks (Åsgard and Draupne formations) on the west side of the Utsira High. The secondary target was to delineate the eastern extent of the 16/1-9 Ivar Aasen oil discovery in Middle Jurassic to Upper Triassic reservoir rocks (Hugin and Skagerrak formations), as well as to investigate Palaeocene (Heimdal formation) and Permian (Zechstein group) reservoir formations.
Well 16/1-16 in the Åsgard formation encountered an approximate 295-foot (90-meter) gross aquiferous sandstone reservoir of variable quality. Furthermore, the well encountered a gross oil column of around 229 miles (70 meters) in the Hugin and Skagerrak formations, of which 91 feet (28 meters) were in a reservoir with very good quality in the Hugin formation. The oil/water contact was not encountered. The oil proven in the well is a different type than the one previously proven in the Ivar Aasen discovery. In addition, the pressure in the oil zone in the Hugin formation and the upper part of the Skagerrak formation is somewhat lower (0.6 bar) than previously observed in the Ivar Aasen discovery. Unlike the western part of the Ivar Aasen discovery, a gas cap was not encountered over the oil in 16/1-16.
No reservoir was encountered in the Heimdal formation. The 95-foot (29-meter) thick Zechstein group, which is composed of dolomites and limestone, is aquiferous and has relatively poor reservoir properties.
The objective of the 16/1-16 A appraisal well, which was drilled just south of 16/1-16, was to determine the oil/water contact. The well encountered a gross oil column of 98 feet (30+ meters) in the Hugin formation. The Hugin formation is about twice as thick as in 16/1-16 and the reservoir quality was very good, as expected. The oil/water contact was encountered at 8,005 feet (2,440 meters) below sea level. This is 19 feet (six meters) deeper than the oil/water contact in the western part of the Ivar Aasen discovery.
Preliminary estimates of the resources proven with 16/1-16 and 16/1-16 A within production licence 457 are between 3 and 6 million standard cubic metres (Sm3) of recoverable oil.
The licensees in production licences 001 B, 028 B and 242 submitted a Plan for Development and Operation (PDO) for the Ivar Aasen discovery to the Ministry of Petroleum and Energy on Dec. 21, 2012. The resources in production licence 457, which were proven with 16/1-16 and 16/1-16 A, are not included in the submitted PDO for Ivar Aasen.
Extensive data acquisition and sampling have been carried out. These are the first and second exploration wells in production licence 457. The licence was awarded in APA 2007. Wells 16/1-16 and 16/1-16 A were drilled to a vertical depth of 8,930 feet and 8,802 feet (2722 and 2683 meters) below sea level, respectively, and were terminated in the Rotliegende group in the Permian and the Skagerrak formation in the Triassic. The wells are permanently plugged and abandoned. Water depth is 370 feet (113 meters).
The wells were drilled by the Bredford Dolphin (mid-water semisub), which has proceeded to production licence 501 in the central part of the North Sea to drill appraisal well 16/3-5, where Lundin Norway AS is the operator.
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