Norwegian state-owned energy giant Equinor and its partners have made an oil and gas discovery in the North Sea, with drilling carried out using Odfjell Drilling’s sixth-generation Deepsea Stavanger rig.
The discovery was made in wildcat wells 15/3-13 S and 15/3-13 A on the Gudrun field in the North Sea, located 50 kilometers north of the Sleipner Øst field in production license 025 and in a water depth of 110 meters, with the wells permanently plugged and abandoned.
Preliminary estimates show that the size of the discovery is between 0.1 and 1.2 million standard cubic meters (Sm3) of recoverable oil equivalent in the intra-Draupne Formation and between 0.4 and 1.3 Sm3 of recoverable oil equivalent in the Hugin Formation.
Well 15/3-13 S encountered thin oil-bearing sandstone layers in the intra-Draupne Formation, while no oil/water contact was encountered. In the Hugin Formation, the well encountered a total of 92 meters of sandstone with poor reservoir properties, the Norwegian Offshore Directorate reported, adding that gas was encountered in two intervals, with respective thicknesses of 8 and 7 meters.
The sidetrack 15/3-13 A was drilled with the objective of delineating the discovery. It encountered oil in an 85-meter thick interval in the intra-Draupne Formation, a total of 13 meters of which were intermittent sandstone layers with moderate reservoir quality. The oil/water contact was proven 4,328 metres below sea level.
According to the Norwegian Offshore Directorate, 15/3-13 A also proved about 100 meters of sandstone with poor reservoir properties in the Hugin Formation. The entire interval was aquiferous, and no gas/water contact was proven.
Well 15/3-13 S was drilled to respective measured and vertical depths of 4,826 meters and 4,740 meters below sea level, while well 15/3-13 A was drilled to respective measured and vertical depths of 4,900 meters and 4,814 meters below sea level.
The licensees, Equinor (operator, 36%), Vår Energi Norge (25%), OMV (Norge) (24%), and Repsol Norway (15%), plan to assess the well results in light of other prospectivity in the area.
Gudrun was discovered in 1975, and the plan for development and operation (PDO) was approved in 2010. The field is developed with a steel jacket and a topside with a process facility and living quarters. It is tied-back to the Sleipner A facility with two pipelines, one for oil and one for wet gas. A PDO exemption was granted for the discovery 15/3-9 in 2013, with production starting in 2014.
In a move to reduce annual emissions from the Norwegian continental shelf (NCS), Equinor earlier this year started partly operating the Gudrun platform, the Sleipnir field center and other associated fields on power from shore. The Gudrun platform was connected to electricity through the existing cable to Sleipner.