--> Abstract: The Norvarg Discovery: Case Study of an Arctic Gas Discovery, by Jeffrey Suiter; #90177 (2013)

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The Norvarg Discovery: Case Study of an Arctic Gas Discovery

Jeffrey Suiter

The Norvarg discovery posed many challenges from technical and logistical standpoints but resulted in the successful execution of the exploration objectives in a remote, environmentally-sensitive area. Located in the Bjarmeland Platform area of the Barents Sea, the discovery well 7225/3-1 was drilled in 2011 within the PL535 license located approximately 275 kilometers north of the Melkøya LNG gas plant in Hammerfest, NO. The main exploration objective was to prove hydrocarbons in Triassic sandstones of the Snadd and Kobbe formations and to evaluate and potentially prove hydrocarbons in the sandstones of the Jurassic Stø formation and Triassic Havert Formation as well as in the carbonates of the Permian Bjarmeland Group. As part of the license obligations, 3D seismic was acquired immediately after license award and the final well location was agreed upon more than 1 year before the planned spud in order to allow for careful logistical and environmental planning for operating Total’s 1st Barents Sea well since 1987. The well was spudded in 377 meters of water on April 30th 2011 and reached a TD of 4150m (-4108.34 m/MSL) on July 12th, in the Permian Limestone (Ulv Fm.) as per requirement. The well has proven gas at all the Mesozoic targets: Stø, Intra-Carnian, Kobbe and Havert. The well has been successfully tested by a DST in the Upper Kobbe (180,000 m3/day on a 44/64” choke), noting that all of the Kobbe reservoirs were encountered in a gas down-to situation at the discovery location. The objectives of the sedimentological interpretation of the cores and borehole image log data were to define the sedimentological model in order to provide deterministic constraints for the construction of the reservoir model. In addition, thanks to the moderate present burial depth, the seismic resolution becomes sufficient to produce seismic attribute maps in the Kobbe. The coherence of core, sidewall core, borehole image and seismic geomorphology data allows good confidence in the interpretation. The Anisian Kobbe formation, holding the majority of the gas accumulation, is made up of stacked heterolithic tidal bars or mouth bars deposited downstream of a very low gradient mature fluvial system. Minor distributary channels must have existed, while very large “anomalous” channels seen on seismic attribute maps may represent local low-stand incised systems. Improvement of reservoir quality and connectivity requires the presence of large sand-filled channels cutting the tidal bar complexes. These channels will be targeted by an appraisal well to be drilled in 2013. Total would like to thank the PL535 license partners for permission to present this abstract: North Energy ASA, Det Norske Oljeselskap ASA, Rocksource ASA, and Valiant Petroleum Norge AS. Total EP Norge would also like to thank all of the technicians and engineers in the Head Offices for their support and suggestions before, during, and following the discovery of Norvarg.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013