--> Abstract: An Example of the Use of 3D Geological Modelling in the Development of the Complex Dunbar Field, UK North Sea, by J. Ritchie, T. Coombes, and S. Hayes; #90937 (1998).

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Abstract: An Example of the Use of 3D Geological Modelling in the Development of the Complex Dunbar Field, UK North Sea.

RITCHIE, JIM and TREVOR COOMBES, Total Oil Marine plc; SEAN HAYES, Reservoir Management Ltd.

The Dunbar Field consists of five hydrocarbon accumulations in three structures within reservoirs of Triassic, Lower and Middle Jurassic age. The early development wells were located in relatively safe positions. Areas which have significant geological risk are now being targeted. These include parts of the field with average permeabilities of less than 1 mD (caused by precipitation of fibrous illite), in which approximately half of the field STOIIP is contained.

The Frontal and Central Panels of the field contain light oil in Middle Jurassic Brent Formation fluvial-deltaic sandstones. These panels are characterised by: major reservoir thickness and sedimentary facies changes across syn-sedimentary faults with resultant differences in reservoir quality, variations in OWC in different reservoir units and very variable vertical and areal permeability distributions.

A series of horizontal wells are planned to develop these low permeability zones, if a pilot well is successful. The well productivity is crucial to the commercial success of this project and the 3D geocellular geological modelling has been essential in the evaluation and visualisation of permeability trends and hence the optimisation of drain trajectory and length.

These models have been constructed using Landmark Stratamodel software. As well as their role in well planning, they are used for accurate volumetric calculations and, after upscaling, are used as input to reservoir simulations.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah