In April 2022, Friso Brouwer of I^3 GEO, conducted an OpendTect webinar in which he showed how high-resolution 3D waveform segmentation can be used for quick geomorphological analysis.

In this post, we show another application of Friso’s workflow. We use the Delft survey, which is freely available from TerraNubis, our cloud portal. Delft is one of several free projects that do not check for license keys, meaning you can run OpendTect Pro and commercial plugins on this dataset.

First, we generated a high-resolution segmentation volume from seismic reflectivity data. (Please note that color inverted data would have been a more suitable input as variations in layer properties are easier to interpret than variations in interface properties). The segmentation into 50 waveforms was done with an Unsupervised Vector Quantizer, a model supported in our Machine Learning plugin.

Next, we created a HorizonCube. We mapped horizons using fast, inversion-based horizon trackers and we used model-driven (proportional, parallel to upper and parallel to lower) modes for detailed infilling. We then QC-ed the HorizonCube in the Wheeler transformed (flattened) domain and mapped additional horizons until all seismic events were flat and correlatable. In total, we mapped 10 horizons.

In the video, we first show a seismic inline and the corresponding data in the Wheeler scene. We QC the HorizonCube with a 2D HorizonCube slider. Notice the flatness of seismic events in Wheeler space. Next, we slice through the waveform segmentation volume with a 3D HorizonCube slider. We observe interesting patterns emerging at different depths but we have not attempted interpreting these.