About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract

Line
Petroleum Migration, Alteration, and Remigration 
Within Troll Previous HitFieldNext Hit, Norwegian Previous HitNorthNext Hit Previous HitSeaNext Hit
1

I. Horstadand S. R. Larter3

Line
ABSTRACT

Troll Previous HitfieldNext Hit represents the largest petroleum discovery within the entire Previous HitNorthNext Hit Previous HitSeaNext Hit area in oil equivalents, with 74% of the accumulated petroleum present as dry gas and 26% as a heavy biodegraded oil leg. The Previous HitfieldNext Hit is divided into several provinces based on the distribution of gas and oil, and the gas and oil have been suggested to be cogenetic. The migration and filling model presented in this paper suggests that the oil and gas represent two different migration phases and that gas migration and filling predate oil emplacement. Two different oil populations have been characterized and mapped in Troll Previous HitfieldNext Hit applying conventional geochemical techniques. We suggest that the two oil populations migrated into the structure through two different migration systems. Oil and gas were subsequently biodegraded within the reservoir. The two oil populations have been found in neighboring oil and gas discoveries, and an oil-oil correlation with these discoveries has been used to determine the location of Previous HitfieldNext Hit filling points and regional migration routes. When oil biodegradation terminated, fresh oil continued to migrate into the reservoir and mixed with the residue of the biodegraded oil. The Previous HitfieldNext Hit was tilted downward to the west in the Neogene, and oil and gas remigrated within the Previous HitfieldNext Hit with a possible spillage of gas. Tilting resulted in a dominantly upward movement of the oil phase whereas gas migrated laterally. Residual oils in the water zone 


©Copyright 1997. The American Association of Petroleum Geologists. All rights reserved.

1Manuscript received July 18, 1995; revised manuscript received March 14, 1996; final acceptance August 16, 1996.

2Saga Petroleum a.s., Kjørboveien 16, P.O. Box 490, N-1301 Sandvika, Norway.

3Newcastle Research Group, Drummond Building, University of Newcastle upon Tyne, Newcastle-upon-Tyne NE1 7RU, United Kingdom.

We would like to thank the partners in the Troll license who allowed us to publish these results. Per Erling Johansen and Tone Molvik are acknowledged for the analytical work, and Snorre Olaussen, Nigel Mills, and Terje Hellem are thanked for helpful discussions and for assistance with the back tilting of the IRAP reservoir Previous HitfieldTop model. Jill Sonrier is acknowledged for typing. We acknowledge K. M. Wolgemuth, John F. Brint, and two anonymous reviewers for helpful comments that improved the paper significantly.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Protected Document: $10
Internal PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].