Wellesley Proves Oil and Gas in Gnomoria in Norwegian North Sea

Wellesley Petroleum AS has made an oil and gas discovery in the first appraisal well to be drilled under Production License 1184 S, an area on the Norwegian side of the North Sea.

Gnomoria well 35/10-12 S is estimated to hold 800,000 to four million cubic meters (28.3 million to 141.3 million cubic feet) of recoverable oil equivalent based on preliminary findings, the Norwegian Offshore Directorate said in a statement Wednesday. The reserves correspond to five million to 25 million barrels of oil equivalent (MMboe).

“Gnomoria is located in an area with multiple discoveries”, the Directorate said. “The licensees are considering a tie-back to existing infrastructure in the area”.

Wellesley chief executive Chris Elliott said in a separate statement, “Although modest in size, the discovery has favorable characteristics which we are confident will allow commercial recovery”.

The well, drilled to a vertical depth of 3,346 meters (10,977.7 feet) by COSL Drilling Europe AS’ COSLPromoter rig, has been permanently plugged and abandoned, according to the agency.

Production License 1170, issued under the 2022 Awards in Predefined Areas, is operated by Wellesley with a 10 percent stake. Norway’s majority state-owned Equinor ASA holds the remaining 90 percent.

The exploration campaign aimed to prove petroleum in the Upper Jurassic sandstones in the Heather Formation. “The well was drilled upflank where reservoir quality was considered to be better for delineation of the Gnomoria discovery from 2018”, the Directorate said.

Wellesley already discovered oil in Gnomoria in 2018 through wildcat well 35/10-4 A. However, according to the Directorate, production is “unlikely”.

“Well 35/10-12 S encountered an 11-meter [36.1 feet] gas column and an 18-meter [59.1 feet] oil column in the Heather Formation, in a sandstone layer totaling 21 meters [68.9 feet] with poor to moderate reservoir quality”, it said. “The gas/oil contact was encountered 3239 meters [10,626.6 feet] below sea level. The oil/water contact was not encountered”.

“The well was not formation tested, but extensive data acquisition and sampling were carried out”, the Directorate added.

In a separate drilling campaign by Wellesley in the North Sea, the company saw two wells in Production License 248 C declared dry this year.

Well 35/11-29 S, or Troppand East, targeted Middle Jurassic reservoir rocks in the Brent Group and the Oseberg Formation.

Wellesley is the operator of the well while Equinor is the operator of 248 C, which was carved out of Production License 248 in 2013, according to the Directorate. Petoro AS holds a majority 40 percent stake in the license while Equinor and Wellesley own 30 percent each.

“PL 248 C is working to identify additional resources to the ‘Swisher’ discovery to make a development more robust as part of Equinor's Ring Road West project”, the Directorate said in a press release June 14.

The two-well Swisher discovery, announced September 2020, was estimated to hold two million cubic meters (70.6 million cubic feet) to six million cubic meters (211.9 million cubic feet) of oil equivalent. The figures correspond to 13 MMboe to 38 MMboe, according to Equinor at the time.

“The licensees will evaluate the discovery for a potential tie-in to existing infrastructure in the area”, it said in a news release September 29, 2020.

In the other 248 C well declared dry this year, 35/11-28 S or Harden Sør, drilling targeted Upper Jurassic reservoir rocks in the Heather Formation.

Seven wells have been drilled in license 248 C so far, three declared dry, according to the Directorate.

Read the latest issue of the OGV Energy magazine HERE