Analysis of effect of using estimated shear wave data as compared to measured compressional and shear wave sonic log

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dc.contributor.advisorSmith, Georgeen_ZA
dc.contributor.authorOghenekohwo, Felix Onovugheen_ZA
dc.date.accessioned2014-07-30T17:27:34Z
dc.date.available2014-07-30T17:27:34Z
dc.date.issued2010en_ZA
dc.descriptionIncludes abstract.
dc.descriptionIncludes bibliographical references (leaves 93-97).
dc.description.abstractThis study is aimed at developing a workflow, and ultimately a model, for quantitative interpretation of sonic and seismic data. Measured data collected at the point of logging can be fraught with errors that can lead to wrong interpretation. One of such data is the shear wave velocity which in most cases is collected with the compressional wave velocity. The measured shear wave velocity log may contain errors that are due to drilling conditions, mud invasion etc. It may also contain cycle skips and might contain a lot of missing data and information. It is because of the poor quality of this type of log that has often made well log analysis companies and log interpreters neglect the measured shear wave log and subsequently generate or create an estimated shear wave log which they use for interpretation and modelling to check how the amplitudes vary with increasing offsets, among other uses.The workflow presented in this study considers the effect of working with the measured data, a reprocessed shear wave log and a locally estimated shear wave log. Specific correction procedures for invasion of the logs was done and synthetic seismograms were created for each type after correction for comparison to a 3D seismic data. The results of this study suggest that oil based mud invasion can cause significant problems to sonic logs especially the shear wave log. It also suggests that, if a shear wave log is of low or bad quality, a reprocessed shear wave log would be better for interpretation and modeling rather than a locally calibrated shear wave log or an estimated shear wave log using global predictions. The conclusion is evident from the synthetics generated using the measured shear wave data and the estimated shear wave data.en_ZA
dc.identifier.apacitationOghenekohwo, F. O. (2010). <i>Analysis of effect of using estimated shear wave data as compared to measured compressional and shear wave sonic log</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Geological Sciences. Retrieved from http://hdl.handle.net/11427/4216en_ZA
dc.identifier.chicagocitationOghenekohwo, Felix Onovughe. <i>"Analysis of effect of using estimated shear wave data as compared to measured compressional and shear wave sonic log."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Geological Sciences, 2010. http://hdl.handle.net/11427/4216en_ZA
dc.identifier.citationOghenekohwo, F. 2010. Analysis of effect of using estimated shear wave data as compared to measured compressional and shear wave sonic log. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Oghenekohwo, Felix Onovughe AB - This study is aimed at developing a workflow, and ultimately a model, for quantitative interpretation of sonic and seismic data. Measured data collected at the point of logging can be fraught with errors that can lead to wrong interpretation. One of such data is the shear wave velocity which in most cases is collected with the compressional wave velocity. The measured shear wave velocity log may contain errors that are due to drilling conditions, mud invasion etc. It may also contain cycle skips and might contain a lot of missing data and information. It is because of the poor quality of this type of log that has often made well log analysis companies and log interpreters neglect the measured shear wave log and subsequently generate or create an estimated shear wave log which they use for interpretation and modelling to check how the amplitudes vary with increasing offsets, among other uses.The workflow presented in this study considers the effect of working with the measured data, a reprocessed shear wave log and a locally estimated shear wave log. Specific correction procedures for invasion of the logs was done and synthetic seismograms were created for each type after correction for comparison to a 3D seismic data. The results of this study suggest that oil based mud invasion can cause significant problems to sonic logs especially the shear wave log. It also suggests that, if a shear wave log is of low or bad quality, a reprocessed shear wave log would be better for interpretation and modeling rather than a locally calibrated shear wave log or an estimated shear wave log using global predictions. The conclusion is evident from the synthetics generated using the measured shear wave data and the estimated shear wave data. DA - 2010 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2010 T1 - Analysis of effect of using estimated shear wave data as compared to measured compressional and shear wave sonic log TI - Analysis of effect of using estimated shear wave data as compared to measured compressional and shear wave sonic log UR - http://hdl.handle.net/11427/4216 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/4216
dc.identifier.vancouvercitationOghenekohwo FO. Analysis of effect of using estimated shear wave data as compared to measured compressional and shear wave sonic log. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Geological Sciences, 2010 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/4216en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Geological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherGeological Sciencesen_ZA
dc.titleAnalysis of effect of using estimated shear wave data as compared to measured compressional and shear wave sonic logen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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