Browsing by Author "Ferguson, Robert James"
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Item Open Access 3D data interpolation and denoising by an adaptive weighting rank-reduction method using singular spectrum analysis(2022-01) Bayati, Farzaneh; Trad, Daniel Osvaldo; Ferguson, Robert James; Innanen, Kristopher; Lamoureux, Michael PhilipA difficult challenge in seismic processing and imaging is to address insufficient and irregular sampling. Most processing algorithms require well-sampled data, which involves small sampling intervals with a regular distribution. This motivates us to find new techniques that are more efficient in interpolating seismic data. The primary objective of this thesis is to study Singular Spectrum Analysis (SSA) as a tool for the reconstruction and denoising of seismic data. An overview of the methods of seismic interpolation and the potential use of SSA in time series is described. SSA as a rank-reduction method for 2-D and 3-D seismic data interpolation is studied. The rank-reduction step of SSA is improved by proposing an adaptive rank-reduction method. To improve the algorithm in denoising an adaptive weighting rank-reduction algorithm is proposed. SSA is compared with the Minimum Weighted Norm Interpolation (MWNI) algorithm. Results obtained in this work demonstrate that SSA is a promising method for simultaneous denoising and reconstructing seismic data.Item Open Access Application of multiple reflections in seismic imaging(2023-11-17) Huang, Shang; Trad, Daniel Osvaldo; Dettmer, Jan; Innanen, Kristopher A.H.; Ferguson, Robert James; Karchewski, Brandon Anthony James; Sacchi, Mauricio DinoMultiple reflections in seismic imaging provide additional information and insights into subsurface structures. However, their practical utilization could be improved due to their complex interaction with the subsurface and interference with primary reflections and noise. This thesis aims to use multiples in seismic imaging in two contexts: classical and machine learning imaging. For the first context, I attempt to extend aperture illumination in a phase shift plus interpolation (PSPI) migration by adding scattering terms in the phase-shift wavefield propagation operator. This method iteratively adds scattering terms for each reflector as the source and receiver wavefields propagate downward into the subsurface, which helps in efficiently extending the illumination of horizontal reflector edges. In the second context, I consider improving images from reverse time migration (RTM). RTM with multiple reflections (RTMM) can improve illumination but suffers from interferences between different orders of multiples. To overcome this limitation, I proposed a method based on a convolutional neural network (CNN) and U-Nets that approximates the inverse of the Hessian similarly to least squares migration, but with less computational cost. The U-NET is trained to learn patterns representing the relation between the reflectivity obtained through RTMM and the true reflectivity. I further developed this by adding a discrete wavelet transform (DWT) input channel which provides an additional constraint that helps to enhance image resolution. Finally, as a key application of the above techniques, I consider the problem of time-lapse seismic monitoring which attempts to detect very weak signal differences produced by changes in reservoirs. This technique is affected by changes in the near-surface noise and insufficient illumination to detect the weak changes. I proposed a novel method that leverages stacked long short-term memory (SD-LSTM) and U-Net neural networks to predict and mitigate noise in monitor data. I test the method in a field dataset, DAS VSP data from the CaMI FRS project. The output provides meaningful information and prediction for CO2 injection migration within a target area. This result aligns closely with the CaMI FRS project CO2 injection plan, providing valuable insights for monitoring the CO2 migration paths for the Basal Belly River Sandstone Formation.Item Open Access P-S seismic inversion: modeling, processing and field examples(1996) Ferguson, Robert James; Stewart, Robert R.Item Open Access Seismic imaging in heterogeneous anisotropic media by nonstationary phase shift(1999) Ferguson, Robert James; Margrave, Gary F.