|
Data Interrogation Strategies |
1 Department of Geotechnology, Delft University of Technology, , Mijnbouwstraat 120, 2628 RX Delft, The Netherlands
3 Quantitative Imaging Group, Delft University of Technology, , Lorentzweg 1, 2628 CJ Delft, The Netherlands
The parametric quantification of geological bodies from high-resolution seismic data helps in understanding and predicting their occurrences, but is often hampered by layer distortions caused by post-depositional processes. A method called GeoTime cube is presented that overcomes this by creating a seismic volume between two near-isochronous geological markers in which the vertical axis corresponds approximately to relative geologic time. This volume is no longer affected by post-depositional deformations, a feature that greatly facilitates the extraction of sedimentary elements of interest. A case study of a fluvio-estuarine reservoir from Suriname demonstrates how fluvial point bars, channel fills and crevasse splays can be extracted from the GeoTime cube. Their geometries are quantified with the help of recent analogues. Meandering rivers are found to show relatively constant curvatures and a characteristic spacing of their meander loops. Cubic splines are suitable parametric descriptors of such river paths. Point bars are their main depositional product and can be approximated by two intersecting circle segments, representing the initial and the final position of the meander loop. The axis joining the circle centres corresponds to the direction of accretion, and the normals to these axes describe the drainage trend. Knowledge of these parameters from a limited area can be used to stochastically model the meander belt in the up- and downstream direction.
