Tertiary Deep-Marine Reservoirs of the North Sea Region
Discovery of the Arbroath, Montrose and Forties fields initiated intensive exploration of the Tertiary deep-marine play in the North Sea region. Subsequent discoveries demonstrated the success of this play and the geological diversity of the depositional systems. The play is now mature and in many areas the remaining exploration potential is likely to be dominated by small, subtle traps with a major component of stratigraphic trapping. Economically marginal discoveries need an in-depth understanding of subsurface uncertainty to mitigate risk with limited appraisal wells. Mature fields require detailed geological understanding in the search for the remaining oil. This volume focuses on the regional depositional setting of these deep-marine systems, providing a stratigraphic and palaeogeographical context for exploration, and development case histories that outline the challenges of producing from these reservoirs. The fields are arranged around the production life cycle, describing the changing needs of geological models as the flow of static and dynamic data refines geological understanding and defines the nature of new opportunities as fields mature.
Depositional controls on fluid flow in the Gannet A Field
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Published:January 01, 2015
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CiteCitation
Gwilym J. Lynn, Morgan Bacciotti, Pim F. Van Bergen, Kirsten R. Gray, 2015. "Depositional controls on fluid flow in the Gannet A Field", Tertiary Deep-Marine Reservoirs of the North Sea Region, T. McKie, P. T. S. Rose, A. J. Hartley, D. W. Jones, T. L. Armstrong
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Abstract
The Gannet A Field is an Eocene-aged Tay Sandstone Member reservoir located in the Central North Sea, with a thin oil rim and overlying gas cap that was developed in the early 1990s. The field comprises a very high quality reservoir and is connected to a large and active aquifer. These two factors in combination have led to a highly dynamic system during production, with significant migration of fluids around the field as offtake evolved. A considerable amount of surveillance data, including time-lapse (4D) seismic data, oil geochemical sampling and cased-hole saturation logs, has been acquired that allows the fluid flow and contact movement within the reservoir to be tracked. Integration of the individual datasets has allowed the key controls on fluid flow in the reservoir to be determined. The depositional architecture has strongly influenced reservoir behaviour, with the positioning and geometry of the non-net facies being the primary control on fluid flow, water-cut development and fluid distributions throughout the field. This has been demonstrated through static and dynamic reservoir modelling and validation of the results with the surveillance data.
- aquifers
- Atlantic Ocean
- Cenozoic
- compartmentalization
- cores
- correlation
- deposition
- depositional environment
- Eocene
- facies
- fluid flow
- gamma-ray methods
- geochemical methods
- geometry
- geophysical methods
- geophysical surveys
- migration
- North Atlantic
- North Sea
- oil and gas fields
- Paleogene
- petroleum
- production
- reservoir rocks
- saturation
- seismic methods
- surveys
- Tertiary
- time-lapse methods
- well-logging
- Horda Formation
- Forties Sandstone Member
- Gannet A Field
- Tay Sandstone Member