Seismic volume attribute analysis of the Cenozoic succession in the L08 block (Southern North Sea)

Three-dimensional volume attribute extraction techniques have been applied to the Cenozoic succession, in a 3-D seismic data volume from the L08 block in the Dutch sector of the North Sea. Volume attribute analysis aims at the extraction of 3-D signal characteristics that are relevant to the geological interpretation of the data. For instance, the spatial discontinuities that are associated with faults or abrupt stratigraphic changes are very well brought forward by the volume attributes. The attributes are computed by means of a 3-D sliding-volume spectrum analysis. The slope of the signal is determined as the mean dip of a local 3-D dip-frequency spectrum. The volume dip and azimuth of the signal have been obtained by combining the average slopes in two directions The Cenozoic succession in the L08 block can be subdivided into two main packages, which are separated by the Mid-Miocene Unconformity (MMU). In the lower package, a complicated fault pattern was observed, which could be mapped in detail using the volume attribute slices. The package above the MMU consists of Neogene sedimentary units that constitute of delta deposits. Using only volume dip and reflection strength attribute slices, we obtained more insight in the delta sequences in a short time. Subsurface objects that may remain unnoticed when using only traditional interpretation techniques can often be easily detected on the attribute maps. Several interesting features could be identified on the volume attribute images, such as slumps, a large submarine fan and channels.