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dc.contributor.advisorStewart, Robert R.
dc.creatorQi, Chen 1989-
dc.date.accessioned2015-08-16T03:01:15Z
dc.date.available2015-08-16T03:01:15Z
dc.date.createdMay 2013
dc.date.issued2013-05
dc.identifier.urihttp://hdl.handle.net/10657/961
dc.description.abstractApparent attenuation resulting from interbed multiples is conveniently expressed by Margrave’s nonstationary convolution model. A few examples of nonstationary processes are time migration, normal-moveout corrections, and forward and inverse Q filtering. Any nonstationary but linear effect can be included in the nonstationary model by an appropriate modification to the convolutional matrix. By embedding pure propagating wavelets at each earth interface in the convolutional matrix, nonstationary convolution replicates the effects of interbed multiples in the output matrix. These propagating wavelets in highly cyclic sequences, such as coal beds, include significant time delays of the primary energy, high-frequency transmission loss and a decrease of seismic resolution for primary energy contaminated with interbed multiples. Because each column vector in the convolution matrix is associated with a primary-only reflection coefficient, the aligned convolution matrix is better defined as a wavelet dictionary. A major goal in data processing is to convert the various time series in the wavelet dictionary into short propagating wavelets that are not time varying. To assist in this task, the wavelet dictionary time series were approximated with minimum-phase equivalent Gaussian pulses. As a measure of success, nonstationary convolution with the wavelet dictionary provided a much better synthetic match to field data than the conventional synthetic seismogram and it duplicated the results of the exact all internal multiple algorithm. By studying the computed wavelet dictionary, a time delay of 25.6ms/1000ft (304m) and energy loss of 74dB loss/1000ft (304m) for primary energy were observed beneath the coal beds. The two parameters needed to estimate the Gaussian function from the wavelet dictionary amplitude spectra offer insight for designing future data processing algorithms to correct for the coal bed effects. However, the assumption of minimum-phase spectra for the Gaussian wavelets needs further work or different wavelets need are needed to approximate the wavelet dictionary.
dc.format.mimetypeapplication/pdf
dc.language.isoeng
dc.rightsThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).
dc.subjectmultiples
dc.subjectattenuation
dc.subjectnonstationary convolution
dc.subjectdeconvolution
dc.subjectseismic
dc.subjectdata processing
dc.subjectwell-tie
dc.subject.lcshGeophysics
dc.titleSeismic characterisation of coal interbed multiples in Cooper Basin, Australia
dc.date.updated2015-08-16T03:01:15Z
dc.type.genreThesis
thesis.degree.nameMaster of Science
thesis.degree.levelMasters
thesis.degree.disciplineGeophysics
thesis.degree.grantorUniversity of Houston
thesis.degree.departmentEarth and Atmospheric Sciences, Department of
dc.contributor.committeeMemberHilterman, Fred J.
dc.contributor.committeeMemberChesnokov, Evgeny
dc.contributor.committeeMemberBell, Lee
dc.type.dcmiText
dc.format.digitalOriginborn digital
dc.description.departmentEarth and Atmospheric Sciences, Department of
thesis.degree.collegeCollege of Natural Sciences and Mathematics


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