Compound seismic modelling of Deep-Water clastic outcrop analogues
|Location||International Geological Congress,oslo 2008|
|Author||Bakke, Kristina; Petersen, Steen Agerlin; Martinsen, Ole Jacob; Lien, Trond|
|Holding Date||28 September 2008|
Deep-water clastic reservoirs are highly variable in size, geometry and internal character with key differences at or below seismic resolution. Reservoir thickness is typically expressed by a single cycle event, and wells are often spaced too far apart making correlation difficult. In order to be able to predict reservoir architecture, trapping styles and in-place hydrocarbon volumes, detailed knowledge about the characterisation of the different depositional systems is needed.
Forward seismic modelling of outcrop analogues can guide quantitative analysis of seismic amplitudes and improve our understanding of seismic data. Increased research has enabled seismic modelling to advance from simple ray tracing into fast convolution based synthetic seismic. These models integrate subsurface petrophysical properties (velocity and density) with interpreted lithology distribution and reservoir architecture from outcrop analogues. The synthetic seismic is compared with seismic data from the studied depositional system, and adjusted to find the Earth model that gives a seismic response that matches the real seismic amplitudes.
Seismic modelling of outcrop analogues is carried out at the scale of individual reservoir elements, such as for deep-water channels or sheets (The Ainsa II Turbidite System, Spain) and at basin scale (Shannon Basin, Ireland). The latter is unusual, mainly because of outcrop limitations, but has significant advances for calibrating seismic stratigraphy to lithology. This study not only increases the understanding of the anticipated seismic character and imaging of the deep-water outcrops. More importantly, it reveals the expected seismic architecture and character of similar deep-water deposits and basin fills and increases the predictive ability in hydrocarbon-bearing basins.