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.
Sedimentological evolution of Sele Formation deep-marine depositional systems of the Central North Sea Available to Purchase
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Published:January 01, 2015
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CitationJames Eldrett, Efthymios Tripsanas, Christopher Davis, Tom McKie, Manuel Vieira, Peter Osterloff, Tom Sandison, 2015. "Sedimentological evolution of Sele Formation deep-marine depositional systems of the Central North Sea", 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 Paleocene–Eocene-aged Sele Formation is developed across the basinal region of the Central North Sea. The section comprises a number of deep-marine fan systems that expanded and contracted across the basin floor in response to relative sea-level changes on the basin margin and fluctuating sediment yield off the Scottish landmass modulated by climate and hinterland uplift. Persistent sediment entry points to the basin resulted in the development of discrete axial and transverse fan fairways with a geometry dictated by an irregular bathymetry sculpted by differential compaction across Mesozoic faults, halokinesis and antecedent fan systems. A high-resolution biostratigraphic framework has allowed the evolution of fan-dispersal systems in response to these effects to be tracked across the basin within four genetic sequences. The proximal parts of the fans comprised channel complexes of low sinuosity, high lateral offset, and low aggradation. The development of these systems in a bathymetrically confined corridor of the Central Graben (c. 65 km wide), combined with high sediment supply, resulted in the eventual burial of any underlying relief. The behaviour of sand-rich reservoirs in this region is dominated by the permeability contrast between high-quality channel fairways and more heterolithic overbank regions, with the potential for early water breakthrough and aquifer coning in the channel fairways, and unswept volumes in overbank locations. Compartmentalization of compensationally stacked channel bodies occurs locally, with stratigraphic trapping caused by lateral channel pinch-outs, channel-base debrites, mud-rich drapes and abandonment fines. Towards the southern part of Quadrant 22, approximately 150 km down-palaeoflow, the systems became less confined and in this region are dominated by channel–lobe complexes, which continued to interact with an irregular bathymetry controlled by antecedent fans, mass-transport complexes and halokinesis in the form of rising salt diapirs. Reservoirs in this region are inherently stratigraphically compartmentalized by their heterolithic lithology and compensational stacking of lobes, and further complicated by structuration and instability induced by the diapiric or basement structures needed to generate a trapping structure in these settings.
- Atlantic Ocean
- bathymetry
- bottom features
- Cenozoic
- Central Graben
- channels
- clastic rocks
- cores
- cyclostratigraphy
- deep-sea environment
- deep-sea sedimentation
- depositional environment
- diapirs
- distribution
- erosion
- geophysical methods
- geophysical profiles
- geophysical surveys
- gravity flows
- landform evolution
- lithofacies
- lithostratigraphy
- mapping
- marine environment
- marine sedimentation
- mass movements
- mechanism
- North Atlantic
- North Sea
- ocean basins
- ocean floors
- oil and gas fields
- paleo-oceanography
- paleobathymetry
- Paleocene
- Paleogene
- paleorelief
- parasequences
- provenance
- reservoir properties
- reservoir rocks
- salt tectonics
- sea-level changes
- sediment supply
- sediment transport
- sediment yield
- sedimentary rocks
- sedimentary structures
- sedimentation
- seismic methods
- seismic profiles
- sequence stratigraphy
- slumping
- submarine fans
- succession
- surveys
- tectonics
- terrigenous materials
- Tertiary
- transport
- traps
- well logs
- Sele Formation
- Maureen Formation
- Lista Formation
- Moray Group
- Dornoch Formation
- Forties Sandstone Member
- Cromarty Sandstone Member
- Gannet Sandstone Member
- lobe complexes
- Bittern Sandstone Member
- Upper Dornoch Formation
- fairways