Detection of geobodies in 3D seismic using unsupervised machine learning

Abstract

In this work, we present a novel, automated method for detecting geobodies in 3D seismic reflection data, helping to reduce interpreter bias and speed up seismic interpretation. A seismic geobody refers to a geometrical, structural, or stratigraphic feature, such as a channel, turbidite fan, or igneous intrusion. Geobodies are subtle seismic features, hard to pick, and their detection is challenging to automate due to their complex 3D geomorphology and diversity of shapes. Nevertheless, the detection and delineation of these structures are essential for improving the understanding of the subsurface as well as building a variety of conceptual models. In our approach, we can rapidly interpret large 3D seismic volumes using point cloud-based segmentation to identify geobodies of interest, including complex stratigraphic features like lobes and channels. By converting the 3D seismic cube into a 3D seismic point cloud (sparse cube), we reduce the volume of data to analyse, which in turn speeds up the detection process. First, we build the 3D point clouds by filtering the seismic reflection volume using different seismic attributes, and then each point in the cloud is segmented into different clusters. The clustering is performed using the unsupervised Density-Based Spatial Clustering of Applications with Noise (DBSCAN) which allows the segmentation of all structures present into delineated objects. The clustered objects can then be characterised by features based on their 3D shape and spatial amplitude distribution. Finally, our method allows the selection of a specific geobody and can retrieve geobodies based on their similarity to exploration targets of interest. The method has been applied successfully to two modern 3D seismic datasets (Falkland Basins) and two types of geobodies: fans and sill intrusions. We demonstrate that our method can scan through a large 3D seismic volume and automatically retrieve likely fan and sill geobodies in a very efficient manner. This approach can be used to scan through large volumes of 3D seismic, looking for a wide variety of geobodiesJames Watt Scholarshi

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