Norwegian oil company Equinor has completed the appraisal drilling on the Sigrun oil and gas discovery in the North Sea offshore Norway lifting its previous resource estimate for the discovery. Equinor is thinking of potentially developing the discovery via the nearby Gudrun platform.
The objective of the well was to delineate the 15/3-4 discovery in three reservoir zones in the Middle Jurassic (the Hugin formation). The discovery was proven in reservoir rocks from the Middle Jurassic in the Brent group in 1982.
Before the appraisal well 15/3-11 was drilled, Equinor’s resource estimate for the discovery was between 0.3 – 1.4 million Sm3 of recoverable oil equivalents.
The well encountered a total oil column of about 35 meters in the Hugin formation, of which about a 15-meter thick sandstone layer with poor to moderate reservoir quality.
The oil/water contact was not encountered. Preliminary estimates of the size of the discovery after the delineation well are between 1.1 and 2 million standard cubic meters (Sm3) of recoverable oil equivalents. The well was not formation-tested, but extensive data acquisition and sampling have been carried out, the Norwegian Petroleum Directorate said.
Development over Gudrun?
The licensees in production license 025 will assess the profitability of the discovery with regard to a potential development over the Gudrun field, NPD said. The appraisal well was drilled about 10 km southeast of the Gudrun field in the North Sea, and about 225 km west of Stavanger.
This is the 9th exploration well in production license 025. The license was awarded in licensing round 2-A in 1969.
Appraisal well 15/3-11 was drilled to a vertical depth of 3991 meters below the sea surface and was terminated in the Sleipner formation in the Middle Jurassic. Water depth at the site is 109 meters. The well has been permanently plugged and abandoned.
The well was drilled by the Deepsea Bergen semi-submersible drilling rig which will now drill wildcat well 35/10-4 S in production license 630 in the northern part of the North Sea, where Equinor Energy AS is the operator.