Neptune Energy Norge AS, operator of the Dugong prospect in the North Sea, will consider tie-in of an oil discovery in the Rannoch and Draupne formations near Snorre field. The discovery well 34/4-15 S and the down-dip sidetrack 34/4-15 A proved oil in the Viking and Brent groups in production license 882.
Preliminary estimates place the size of the Rannoch formation discovery at 5-14 million standard cu m of recoverable oil. Preliminary estimates place the size of the discovery in the Intra Draupne formation at 1.6-5 million standard cu m of recoverable oil.
The wells were drilled about 10 km northwest of Snorre field and 160 km west of Florø to respective vertical depths of 3,430 and 3,573 m subsea and respective measured depths of 3,571 and 3,844 m subsea. The wells were terminated in rocks from the Early Jurassic Age (the Drake formation). Water depth at the site is 332 m. The wells will now be permanently plugged.
The primary exploration target for well 34/4-15 S was to prove petroleum in reservoir rocks from the Middle Jurassic Age (the Rannoch formation). The secondary exploration target was to prove petroleum in reservoir rocks from the Late Jurassic Age (Intra Draupne formation sandstone).
An oil column of about 80 m was encountered in the primary exploration target in the Rannoch formation, 50 m of which are sandstone with generally moderate reservoir quality. The oil-water contact was not encountered.
A sandstone layer of a few meters was encountered in the secondary exploration target in the Intra Draupne formation, with poor reservoir quality and traces of petroleum.
The primary objective of well 34/4-15 A was to delineate the discovery in well 34/4-15 S in the Rannoch formation.
The secondary exploration objective was to prove petroleum in reservoir rocks from the Late Jurassic Age (Intra Draupne formation sandstone).
An oil column of about 100 m was encountered in the secondary exploration target in the Intra Draupne formation sandstone, 55 m of which are in sandstone of poor to moderate reservoir quality.
The wells were not formation-tested, but extensive data acquisition and sampling were carried out.
“The discovery gives new and valuable understanding of the subsurface in this part of the Tampen area,” said Steinar Meland, Neptune Energy’s director of exploration and development in Norway. “We will now initiate studies, as well as consider development options for the discovery.”
Neptune’s managing director in Norway, Odin Estensen, said the discovery “may also open up additional opportunities in the surrounding licenses, with the potential for a new core area for Neptune in Norway.”
The wells were drilled by the Deepsea Yantai semisubmersible drilling rig, which will now drill production wells in license 153 on Gjøa field in the northeastern part of the North Sea, where Neptune Energy is operator.
Neptune Energy is operator of Dugong with 40%. Partners are Concedo (20%), Petrolia NOCO (20%), and Idemitsu Petroleum Norge (20%).
