Total encounters oil via Garantiana appraisal well in North Sea

Nov. 3, 2014
Total E&P Norge AS encountered a 120-m total gross oil column with appraisal well 34/6-3 S in the Cook formation on production license 554, 30 km northeast of Visund field in the Norwegian North Sea. The company describes the reservoir quality as “very good.”

Total E&P Norge AS encountered a 120-m total gross oil column with appraisal well 34/6-3 S in the Cook formation on production license 554, 30 km northeast of Visund field in the Norwegian North Sea. The company describes the reservoir quality as “very good.”

The objective of the well was to delineate the 34/6-2 S oil discovery, 2 km to the northeast, made in the Cook formation in the Lower Jurassic in 2012 (OGJ Online, Dec. 3, 2012). The appraisal well reached a measured depth of 4,462 m in 381 m of water.

The secondary target was to prove petroleum in the Statfjord group in the Lower Jurassic, higher up on the structure than well 34/6-2 S. It turned up dry, and the oil-water contact was not encountered.

Preliminary calculation of the size of the oil discovery is 6-14 million standard cu m (scm) of recoverable oil. Prior to drilling the appraisal well, the discovery was estimated to hold 6 million scm of recoverable oil.

Extensive data acquisition and sampling were carried out, including a successful formation test in the Cook formation. The well was tested with a stable production rate of 940 scm/day of oil through a 24/64-in. choke, and with a maximum production rate of 1,100 scm/day of oil through a 28/64-in. choke.

The test showed good flow properties with stable flow pressure and low pressure decline, and consistent pressure build-up. The well produced oil with a gas-oil ratio of 19:1 cu m. Extensive data analyses and studies have started to confirm the resource estimate and to assess possible development solutions.

Wildcat well 34/6-3 A encountered a 12-m net oil column in the Cook formation while attempting to prove petroleum in Early Jurassic reservoir rocks in a separate structure next to the 34/6-2 S discovery.

Well 34/6-3 A was drilled to a measured depth of 4,019 m under the sea surface in 381 m of water. Estimated recoverable resources are up to 500,000 scm of oil.

The secondary exploration target was to prove petroleum in the Statfjord group in the Lower Jurassic. The well was terminated in the Statfjord group, where it was dry. Sampling and data acquisition were carried out, but the well was not formation tested.

These are the third and fourth exploration wells in production license 554, awarded in APA 2009. Both will be permanently plugged and abandoned.

Both wells were drilled by Dryships Inc.’s Leiv Eiriksson semisubmersible drilling facility, which will move on to drill RWE Dea-operated wildcat well 35/9-12 S in production license 420, part of the 2010 Titan discovery in the Norwegian North Sea (OGJ Online, May 27, 2014).