Numerical modelling of pseudo-random seismic sources

Strong, Shaun Regen. (2003). Numerical modelling of pseudo-random seismic sources B.Sc Thesis, School of Physical Sciences, The University of Queensland.

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Author Strong, Shaun Regen.
Thesis Title Numerical modelling of pseudo-random seismic sources
School, Centre or Institute School of Physical Sciences
Institution The University of Queensland
Publication date 2003-01-01
Thesis type B.Sc Thesis
Supervisor Steve Hearn
Total pages 108
Language eng
Subjects 040407 Seismology and Seismic Exploration
Formatted abstract
In this thesis numerical modelling has been used to investigate and describe pseudorandom seismic sources, for the purpose of making these more geophysically competitive with explosive sources. Such research is important, since there is growing public and political pressure to reduce the use of explosive sources (e.g. in environmentally sensitive and populated areas, or due to international security issues.) This thesis focuses on the Vibroseis and Mini-SOSIE surface sources, which are popular in the petroleum and coal seismic industries.

For the vibroseis technique three types of pilot signal have been examined. The common swept-frequency pilot has been taken as a comparative reference. Two pseudo-random alternatives have also been examined namely the full-cycle polarity-reversal and the novel half-cycle polarity-reversal techniques. The half-cycle technique exhibits particular advantages with regard to wavelet shape, harmonic noise, bandwidth, and wavelet interference. However some implementation issues exist, which will require a modification to the standard vibrator operating procedures.

For Mini SOSIE, software stacking and correlation techniques have been examined. These show advantages over real-time hardware stacking, as they allow prestack processing to attenuate noise. Particular processes demonstrated here include predictive deconvolution (to reduce noise due to non-random impact sequences and, sign-bit and median stacking (to reduce effects of high-amplitude cultural noise).
Keyword Seismology -- Numerical modelling

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
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Created: Wed, 12 Oct 2011, 01:49:55 EST by Ms Christine Heslehurst on behalf of Scholarly Communication and Digitisation Service