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RGB colour blending is a powerful technique of co-visualization of different band-limited magnitude volumes created by frequency decomposition. The aims of this study were to investigate the impact of changes in geometry and acoustic impedance on what we observe in a blend of frequency magnitude volumes, and to examine how sensitive different methods of frequency decomposition are to these variations. We present a comparison of frequency decomposition methods applied to the Hermod Member submarine fan system, a well understood fan system from the Northern North Sea, and to simple synthetic models. Observations made from RGB imaging are compared to equivalent results from synthetic models created using well measurements and systematic variations in reservoir parameters. We show that thickness variations between events are the dominant factor controlling RGB colour response and that subtle lithological changes, presented as differences in acoustic impedance, are a second order effect. Furthermore, when the source frequency and decomposition bands of a synthetic wedge model are matched to a real dataset, we can relate colour values directly to thicknesses. In doing so we extend the classical tuning wedge for use as a calibration tool for frequency decomposition colour blends.

The focus of this study is to demonstrate how seismic attributes can be used in the interpretation workflow to rapidly obtain a high-resolution view of the geology that is imaged within a seismic data set. To demonstrate the efficacy of seismic attribute analysis to basin scale reconnaissance, we apply a workflow to seismic data sets from the Exmouth Subbasin, northwestern Australia, with the aim of determining the geologic expression of the subsurface. Of specific interest are Barrow Group Jurassic and Cretaceous fluvial and marine sediments, that were faulted during the Jurassic-Cretaceous rifting associated with the breakup of East Gondwana. Regional-scale interpretations are made to develop a tectonostratigraphic context to the investigation. Target-level analyses, focused on features of exploration interest identified using regional reconnaissance, are made to calibrate attribute response and demonstrate the effectiveness of seismic attributes for rapid evaluation of prospectivity in the initial stages of exploration. The main structural episodes are distinguished using dip and azimuth attributes, and faulting is expressed using a combination of edge attributes which are used to create fault trend lineations. We observe three main structural trends: the main northeast–southwest Jurassic-Cretaceous syn-rift primary fault orientation of 48°, a secondary trend of 108°, taken to represent secondary conjugate faulting and a third trend of 100° interpreted as the reactivation of these faults into the postrift sediments. Stratigraphic attributes that respond to amplitude and frequency are used to create reservoir scale geobodies of faulted Macedon turbidites, which in turn are used for detailed tuning sensitivity analysis. The final part of the investigation is of the syn-rift magmatic system responsible for sills and dikes that exploit the normal fault network. These intrusive and extrusive features are important as are potential drilling hazards and can act as baffles to hydrocarbon migration.

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We present the results of multiattribute imaging and geobody delineation applied to stratigraphic targets such as Jurassic channels and Triassic beaches and spits, imaged in data from the Norwegian sector of the North Sea. Interpretation based on the examination of seismic amplitude alone is challenging due to the complexity and subtleness of these features. To improve the definition of these Mesozoic targets, we have applied a multiattribute approach, combining frequency decomposition, seismic attribute analysis techniques, advanced visualization, and a new method of multiattribute geobody delineation. Attributes have been selected that are sensitive to the edge and magnitude response of sedimentary structures, while the use of narrow band spectral magnitude volumes allows small scale frequency variations to be analyzed. These different sources are corendered using advanced color and opacity blending, providing multiattribute composite image volumes for subsequent interpretation and as input to further geobody delineation. The use of such advanced visualization has resulted in a collection of 3D volumes that successfully distinguish the internal and overbank geometry of chan