New North Sea oil discovery springs up as Othello opens new play in ‘dry belt’

Norwegian oil and gas operator DNO has made a new oil discovery in the southern North Sea on the Norwegian Continental Shelf (NCS), which is described as a play opener in an area previously dubbed ‘the dry belt,’ where little exploration interest got noted in recent years.

DNO has struck oil in a new play within license PL1086 in which the company holds a 50% operated interest with the rest held by its partners: Aker BP (20%), Petoro (20%), and Source Energy (10%). Based on DNO’s preliminary estimates, the light oil discovery, made in Palaeocene sandstones of good reservoir quality, contains gross recoverable resources in the range of 27-57 million barrels of oil equivalent (boe) on a P90-P10 basis, with a mean of 41 million boe.

With no other moveable oil being encountered before in the Borr unit of the Våle Formation in the Norwegian sector, the discovery is considered a play opener. Since the well had two exploration targets, the first was a deeper prospect (Falstaff) where no reservoir was encountered while the second one was a shallower prospect named Othello (2/6-7 S), encountering a 16-meter net oil-bearing reservoir that was subsequently confirmed in a sidetrack (2/6-7 A).

The discovery, made in wildcat well 2/6-7 S in production license 1086 that was awarded in the awards in predefined areas (APA) in 2021, was drilled using Noble Corporation’s Noble Invincible jack-up rig. The preliminary estimates, according to the Norwegian Offshore Directorate (NOD), indicate the size of the discovery is between 4-9 million standard cubic meters of oil equivalent, corresponding to 25-57 million barrels of oil equivalent, as confirmed by DNO.

While the primary exploration target for wildcat well 2/6-7 S was to prove petroleum in Upper Jurassic reservoir rocks in the Ula Formation, the secondary exploration target was to prove petroleum in Palaeocene reservoir rocks in the Borr Member in the Våle Formation. The objective of appraisal well 2/6-7 A was to confirm the size of the discovery in the Borr Member.

While the wildcat well 2/6-7 S encountered an oil column in the Borr Member, spanning two sandstone layers totaling 16 meters with moderate to good reservoir quality, the oil/water contact was not encountered and no reservoir was present in the primary exploration target in the Ula Formation.

Furthermore, the appraisal well 2/6-7 A encountered a 12-meter oil column in the Borr Member, eight meters of which were in a sandstone reservoir. The Borr Member had a total thickness of 39 meters, 26 meters of which was net sand of moderate to good reservoir quality, with a possible oil/water contact encountered at 2,929 meters below sea level.

The wells were not formation-tested; however, extensive data acquisition and sampling were done. The wildcat well 2/6-7 S was drilled to a vertical depth of 3,642 meters below sea level and was terminated in the Smith Bank Formation in the Upper Triassic. The appraisal well 2/6-7 A was drilled to vertical and measured depths of 2,987 meters and 3,386 meters below sea level and terminated in the Ekofisk Formation in the Lower Palaeocene.

The water depth at the site is 56 meters, and the wells have been permanently plugged and abandoned. The Norwegian Offshore Directorate underlines that DNO and its partners will assess the discovery along with other discoveries and prospects in the vicinity, with a view towards potential future development.

According to DNO, the Othello discovery marks the second new play it has proven recently in Norway as the operator, following last year’s Norma gas condensate discovery (operator, 30%) in the Norwegian sector of the North Sea, which it dubbed “exciting” as the preliminary evaluation indicated gross recoverable resources between 25-130 million barrels of oil equivalent (mmboe) on a P90-P10 basis.

Considered a play-opener, the discovery was said to have the potential to de-risk other exploration prospects in that area, with the Norwegian authorities stating that the recoverable gas/condensate volumes of 2–21 million Sm3 were proven.

DNO’s Othello prospect has discovered oil east in the basin where migration risk was commonly thought to be too high. Together with its partners, the company is already considering tying back the discovery to existing infrastructure, contemplating ConocoPhillips’ Ekofisk hub some 40 kilometers to the west and the Valhall hub, operated by Aker BP, some 55 kilometers to the southwest.

Bijan Mossavar-Rahman, Executive Chairman of DNO, commented: “DNO has become a North Sea playmaker. We have proven persistent, purposeful and pertinacious and these qualities pay in exploration. In addition to our ongoing exploration campaign, we will focus on other identified, and now derisked by Othello, prospects in the area.”

Moreover, the licensees of nearby PL1085, comprising DNO (25%), Aker BP (operator, 55%), and Petoro (20%), are considering developing the 2022 Overly discovery in the permit as a tie-back to Aker BP’s Valhall hub based on recently completed studies leading to increased estimates of recoverable resources, since it lies 10 kilometers north of Valhall.

The Noble Invincible ultra-harsh environment jack-up rig, hired for the job in February, will now move to drill a production well on the nearby Tambar East oilfield in which DNO holds a 37.8% interest. In addition, the 2026 Sunndal exploration well is planned to be drilled in PL1171 by DNO (50%) and Aker BP (operator, 50%).