25/8-4 (D-struktur) is a discovery in the central part of the North Sea, eight kilometres northeast of the Grane field. The water depth is 130 metres. The discovery was proven in 1992 and subsequently delineated by well 25/8-18 S in 2014. The main reservoir contains oil in sandstone of Paleocene age in the Heimdal Formation. It is likely that oil is also present in remobilised Heimdal sand, injected into shales overlying the formation. The reservoir lies at a depth of 1,750 metres and has excellent quality. A development solution with subsea templates tied-back to the Grane field is being evaluated.
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