Delineation of oil and gas discovery near the Gjøa field in the North Sea

The wells were drilled about 7 km north of the Gjøa field in the North Sea, and 58 km west of Florø.

The 35/9-3 discovery was proven in reservoir rocks from the Early Cretaceous with generally poor reservoir quality (the Agat Formation) in 1997. Before wells 35/9-16 S and 35/9-16 A were drilled, the operator's resource estimate for the discovery was between 0.62 and 1.12 million Sm³ of recoverable oil equivalent.

The objective of the appraisal wells was to clarify the reservoir quality and hydrocarbon column in the southern part of the Hamlet structure.

Well 35/9-16 S encountered a 58 m gas column and a 34 m oil column in the Agat Formation in sandstone layers totalling 92 m with moderate to poor reservoir quality. The gas/oil contact was encountered at 2624 m below sea level.

Well 35/9-16 A encountered a 35-m oil column in the Agat Formation in sandstone layers totalling 115 m with good to poor reservoir quality. The oil/water contact was encountered at 2663 m below sea level.

The preliminary calculation of the size of the discovery is between 2.2 and 3.4 million Sm³ of recoverable oil equivalent.

The licensees will consider tying the discovery into existing infrastructure in the Gjøa field and will assess the discovery alongside other nearby discoveries and prospects as regards further follow-up.

The wells were not formation-tested, but extensive data acquisition and sampling was undertaken.

These are the 11th and 12th exploration wells in production licence 153. The licence was awarded in the 12th licensing round in 1988.

Appraisal well 35/9-16 S was drilled to a vertical depth of 2720 m below sea level and was terminated in the Sola Formation in the Early Cretaceous.

Appraisal well 35/9-16 A was drilled to a vertical depth and measured depth of 2790 ms and 3015 ms below sea level, respectively, and was terminated in the Sola Formation in the Early Cretaceous.

The water depth is 358 ms and the well has been plugged and abandoned. The wells were drilled by the Deepsea Yantai drilling facility, which will now drill production wells in production licence 586 in the Norwegian Sea, where Neptune Energy Norge AS is the operator.

Read the latest issue of Oilfield Technology in full for free: Spring 2022

Oilfield Technology’s first issue of 2022 begins with analysis from Wood Mackenzie on the disconnect between surging oil prices and US oil production growth and investment. The rest of the issue is dedicated to features covering sand removal technology, dissolvable frac plug technology, digitalisation of offshore operations, annular intervention, oilfield chemicals, subsea compression systems and smart instrument measurement.

Exclusive contributions come from TETRA Technologies, NOV, Archer, Expro, Locus Bio-Energy Solutions, AES Drilling Fluids, MAN Energy Solutions and Winters Instruments.

Read the article online at: https://www.oilfieldtechnology.com/drilling-and-production/13052022/delineation-of-oil-and-gas-discovery-near-the-gja-field-in-the-north-sea/