Deepsea Yantai rig

Neptune wraps up Dugong appraisal well testing

Exploration & Production

Oil and gas company Neptune Energy has completed the formation and flow testing (DST) of an appraisal well on the Dugong discovery located offshore Norway. The submission of the development plan for the discovery is expected by the end of 2022.

Deepsea Yantai rig; Source: Odfjell Drilling

The Dugong discovery, located in Production License 882 in the North Sea, was announced back in July 2020. The licence is operated by Neptune Energy with Petrolia Noco, Idemitsu Petroleum, and Concedo as partners.

Using the Deepsea Yantai rig, the appraisal well 34/4-16 S was drilled and temporarily plugged and abandoned in late March 2021, with plans for a drill stem test at a later stage. The well re-entry started on 2 September 2021.

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The completion of DST of well 34/4-16 S was announced by Petrolia Noco in an update on Thursday.

The well’s main objective was to identify the oil-water contact and delineate the Dugong discovery in the Rannoch formation. A secondary objective was to formation test the reservoir if a sufficient amount of hydrocarbon-bearing sand was encountered.

The well encountered a 25-metre oil column in the Rannoch formation, 22 metres of which consists of sandstone of primarily moderate reservoir quality. The oil/water contact was encountered at a vertical depth of 3443 meters below sea level. Following re-entry of the well, a successful formation test was conducted. In the upper part of the Rannoch formation, a 13-metre section was perforated and delivered a maximum production rate of approximately 2100 bbls/d through a 32/64-inch nozzle opening.

The Dugong discovery was one of the largest discoveries on the Norwegian Continental Shelf in 2020. Dugong is located 158 kilometres west of Florø, Norway, at a water depth of 330 metres, and is close to the existing production facilities of the Snorre field. The reservoir lies at a depth of 3,250 – 3,500 metres.

Following the Dugong appraisal well, the recoverable resources are estimated to be between 40-108 million barrels of oil equivalent. The partnership, with operator Neptune Energy, aims to submit a Plan for Development and Operation for the Dugong discovery by the end of 2022.

The Dugong partners now also plan to drill a well in the Dugong Tail prospect in PL 882. Neptune last June filed an Application of Discharge for well 33/6-6 S in order to test an additional prospect (Shamu) in the licence. According to previous information, the Tail well is planned for the third quarter of 2021.