Bruce Hartley

Physical Modelling of the Virtual Source Method

Physical modelling of the virtual source method has been carried out to demonstrate its imaging capability below multi-scattering surface layer. The imaging has been compared with physical modelling of a conventional seismic experiment with source and re

Application of amplitude thresholding to aid minimum energy adaptive subtraction for multiple attenuation

Model based multiple prediction approaches require an adaptive subtraction step that is able to correct for differences between the real and predicted multiples. The commonly used subtraction process derives shaping operators, in the least squares sense, to minimize the energy difference between the predicted multiples and the field record. Although the minimum energy assumption allows a computationally efficient adaptive subtraction, it can lead to attenuation of primary information. This abstract illustrates how a simple amplitude clipping approach can significantly improve the effectiveness of the least squares adaptive subtraction and minimize primary attenuation.

Prestack hyperspace propagation for automated event picking

Summary Seismic data mining is part of an interactive processing and interpretation workflow. The extraction of information will often have the prerequisite of picking reflection events. Methods that aid in automatically extracting information are required when handling large volumes of data. Migrated 3-D seismic data in prestack form (which includes the offset dimension) creates a 4-D hyperspace. An algorithm for tracking prestack reflection events in that hyperspace will be presented. The algorithm combines a range of techniques including supervised learning. Results of automated picking will be presented for migrated, prestack, field 3-D data. The algorithm was able to track a nominated reflection event in prestack hyperspace from a single seed pick. The results are superior to those produced using a 2-D gather-based approach and a correlation autopicker.

3D Multiple Moveout Wavefield Transformation For Pre-conditioning Data For the Removal of Water Bottom Multiples

Summary Wavefield transformations have been used for many years to precondition seismic data to enhance useful features of the seismic record or to suppress unwanted signal or noise. With the recording of three dimensional seismic surveys it is appropriate to extend the transformations to utilise the 3D data. A 2D Multiple Moveout transformation has been applied previously to the removal of long period multiple reflections with significant success. This removal techniques relies on periodicity of the position of the multiples on the transformed seismic record and the stationarity of the time sequence. This work extends the MMO technique to three dimensions and applies it to simple synthetic data.