Combining seismic surveys to improve data quality

The work presented in this paper is based on seismic data from the Gullfaks Field in the Tampen Spur area, northern North Sea. The field covers an area of approximately 55 km super(2). Total recoverable reserves amount to approximately 310 million Sm super(3) of oil and some 30 billion Sm super(3) of gas in the Jurassic Brent Group, Cook Formation and the Statfjord Formation reservoirs. The Gullfaks Field occupies the eastern half of a major 10-25 km wide NNE-trending fault block and is bounded by faults with kilometre offset to the east and west. Structurally, the field can be separated into three contrasting compartments: a western system with domino-style fault block geometry, a deeply eroded eastern horst complex of elevated subhorizontal layers and steep faults, and a transitional accommodation zone (graben system) which is partly identified as a modified fold structure. The Gullfaks Field is one of the most structurally complex oil fields in the North Sea. Although the seismic data have historically been of generally poor quality, an enormous amount of well data aids understanding of the complex geometry. About 150 wells have been drilled, yielding more than 6 km of cores and 34 km of dipmeter data, together with 110 km of standard log data. An integrated structural analysis of the available data on the field has recently been carried out.