SCAN Special Seismic Products: 3D Cross-spreads and 2D Widelines
During the national seismic campaign, the SCAN programme made use of mainly 2-dimensional lines for their seismic imaging. This is the most cost-efficient way to collect a lot of information for a large area. However, 2D seismic imaging often isn’t sufficient to prepare for a (research) drilling and find a suitable location. A 3-dimensional seismic survey can provide better insight. However, 3D seismic is very expensive. That is why SCAN has investigated two other options for designing the collection of the seismic data.
In the ‘widelines’ method, an additional 2D seismic line is constructed based on data from two parallel lines that run close to each other. The signals from one line are also recorded on the othe line, and vice versa. The ‘cross-spread’ method consists of two or more 2D lines that cross each other at right or oblique angles. Here signals from the shots on lines are also registered on the other lines and vice versa, creating a simple 3D image around the intersections of the lines. Both methods proved successful and can provide the necessary data at a fraction of the cost of a 3D survey or a dense 2D raster. It was concluded that the widelines and cross-spread method have therefore proven to be very useful for the SCAN programme.