Permian carbonates flow 4,300 b/d at Barents Gohta find

A group led by a unit of Lundin Petroleum AB has flow-tested its Gohta discovery in the Barents Sea at 4,300 b/d of oil, confirming for the first time oil and gas in a play model that so far has been unsuccessful on the Norwegian Continental Shelf.

The 7120/1-3 well, in PL492 about 35 km north of Snohvit field, proved oil in contact with an overlying gas cap (OGJ Online, Sept. 10, 2013). The well’s purpose was to prove petroleum in reservoir rocks in Triassic sandstone reservoirs and Permo-Carboniferous carbonate reservoir.

In the carbonate reservoir the well found a 25-m gross gas column above a 75-m gross oil column in karstified and dolomitized limestone. The Triassic sandstone was water bearing.

A production DST performed to assess the quality of the carbonate reservoir yielded a flow rate of 4,300 b/d of oil through a 44/64-in. choke with a gas-oil ratio of 1,040 scf/bbl. The main flow of the reservoir was stable over 24 hr, and the pressure buildup lasted 36 hr and did not show any barriers such as faults or significant reservoir characteristics variations, Lundin Norway AS said.

The well represents the first successful test of Permian carbonate reservoirs on the Norwegian shelf.

The DST confirmed good reservoir production properties. Preliminary evaluation of the gross recoverable oil and gas resources from the Gohta discovery is estimated at 60-145 million bbl of oil and 275-545 bcf of gas.

Lundin Norway, which drilled Gohta to 2,525 m below mean sea level in 342 m of water, said it “will now look to drill similar exploration prospects in adjoining licenses where we have a significant acreage position.”

Interests in PL492 are Lundin Norway and DNO ASA 40% and Noreco Norway AS 20%.