Wintershall Norge AS, operator of production licence 248, is in the process of completing the drilling of a wildcat and appraisal well, in the Norwegian sector of the North Sea.
According to the Norwegian Petroleum Directorate (NPD), the wildcat well 35/11-18 and the appraisal 35/11-18 A have been drilled approx. four kilometres west of the Vega Sør field.
The primary exploration target for well 35/11-18 was to prove petroleum in Middle Jurassic reservoir rocks (the Brent group). The secondary exploration target was to prove petroleum in Upper Jurassic reservoir rocks (sandstones in the Heather formation).
In the primary exploration target, the well encountered the Brent group with a thickness of 275 metres and moderate to good reservoir quality. The well proved light oil in the Tarbert and Oseberg formation, with columns of eleven and three metres, respectively.
In the secondary exploration target, the well encountered an eight-metre hydrocarbon column with good to poor reservoir quality.
The NPD says that the objective of appraisal well 35/11-18 A was to investigate the extent of the reservoir and the hydrocarbon columns, and the well was drilled about 450 metres south of the discovery well. The well proved oil and gas in two Upper Jurassic (the Heather formation) sandstones with net thicknesses of 33 and 24 metres, respectively, with poor to good reservoir quality. The well encountered oil throughout the Brent group, which is 270 metres, with moderate to good reservoir quality. The well also encountered a 46-metre column containing light oil in the Lower Jurassic (the Cook formation). Preliminary estimates place the size of the discovery between 1 and 3 million Sm3 of recoverable oil, the directorate said.
Extensive data collection and sampling have been carried out, including two formation tests in the Cook and Oseberg formation in 35/11-18 A. The tests show good flow properties with stable flow pressure and low pressure fall-off, with good permeability.
The wells are the second and third exploration wells in production licence 248.
Well 35/11-18 was drilled to a measured depth of 3759 metres below the sea surface (3709 metres vertical depth) and was terminated in Early Jurassic rocks (the Cook formation). The appraisal well was drilled to a measured depth of 4020 metres below the sea surface (3874 metres vertical depth), and was terminated in Early Jurassic rocks (the Statfjord group).
Water depth at the site is 366 metres. The NPD says that the wells have been permanently plugged and abandoned and the partners in PL 248 will now evaluate the results.
Wells 35/11-18 & 18 A were drilled by the Borgland Dolphin drilling rig, which will now drill appraisal well 25/10-14 in the North Sea in production licence 571, where Suncor Energy Norge AS is the operator.
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