Multilevel Composition: A new method for revealing complex geological features in three-dimensional seismic reflection data

Advanced seismic data and multi-attribute visualization techniques, such as color blending of attributes, have considerably enhanced the capability of interpreters to characterize geological features in three-dimensional (3D) seismic reflection datasets. However, high resolution investigation of complex, vertically linked geological features such as channel systems and fluid conduits, remains challenging. These features may appear in the dataset as pronounced attribute anomalies, such as high-amplitude or spectrally or structurally enhanced seismic reflectivity bands, at several depth levels. Vertical linkages between these features, however, may not be readily established. We have developed an innovative method, Multilevel Composition, for an intuitive display of vertically connected features. Our method involves the composition of attribute maps from three different depth/time windows or slices onto a single map, in which inter-window/layer depth information is coded in colors. Multilevel Composition starts with the identification of suitable seismic attributes, such as high amplitudes in the examples displayed here, to map features of geological interest. At least one reference horizon is then identified and mapped in the vicinity of the target window of interest. Three sub-windows are then defined with respect to the reference horizon(s) based on the vertical and spatial distribution of the geological features. Relevant seismic attributes are computed for each of the sub-windows, and the resulting maps, one from each sub-window, are assigned basic color channels and are co-rendered to reveal multilevel linkages between these features. We demonstrate the efficacy of this method by applying it to two 3D seismic datasets, one illuminating deep-water depositional elements in the eastern Nile fan, eastern Mediterranean and the other targeting seafloor seeps and underlying gas migration systems beneath the Omakere Ridge, offshore New Zealand. The new method is simple and should be easy to implement to enhance seismic interpretation workflows.