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dc.contributor.advisorSnieder, Roel, 1958-
dc.contributor.authorKnaak, Allison
dc.contributor.committeememberBerger, John R.
dc.contributor.committeememberSava, Paul C.
dc.contributor.committeememberKrahenbuhl, Richard A.
dc.contributor.committeememberSchneider, Jennifer J.
dc.date.accessioned2007-01-03T05:57:04Z
dc.date.available2007-01-03T05:57:04Z
dc.date.issued2015
dc.description2015 Spring.
dc.descriptionIncludes illustrations (some color).
dc.descriptionIncludes bibliographical references (pages 147-155).
dc.description.abstractLocating hydrocarbon reservoirs has become more challenging with smaller, deeper or shallower targets in complicated environments. Controlled-source electromagnetics (CSEM), is a geophysical electromagnetic method used to detect and derisk hydrocarbon reservoirs in marine settings, but it is limited by the size of the target, low-spatial resolution, and depth of the reservoir. To reduce the impact of complicated settings and improve the detecting capabilities of CSEM, I apply synthetic aperture to CSEM responses, which virtually increases the length and width of the CSEM source by combining the responses from multiple individual sources. Applying a weight to each source steers or focuses the synthetic aperture source array in the inline and crossline directions. To evaluate the benefits of a 2D source distribution, I test steered synthetic aperture on 3D diffusive fields and view the changes with a new visualization technique. Then I apply 2D steered synthetic aperture to 3D noisy synthetic CSEM fields, which increases the detectability of the reservoir significantly. With more general weighting, I develop an optimization method to find the optimal weights for synthetic aperture arrays that adapts to the information in the CSEM data. The application of optimally weighted synthetic aperture to noisy, simulated electromagnetic fields reduces the presence of noise, increases detectability, and better defines the lateral extent of the target. I then modify the optimization method to include a term that minimizes the variance of random, independent noise. With the application of the modified optimization method, the weighted synthetic aperture responses amplifies the anomaly from the reservoir, lowers the noise floor, and reduces noise streaks in noisy CSEM responses from sources offset kilometers from the receivers. Even with changes to the location of the reservoir and perturbations to the physical properties, synthetic aperture is still able to highlight targets correctly, which allows use of the method in locations where the subsurface models are built from only estimates. In addition to the technical work in this thesis, I explore the interface between science, government, and society by examining the controversy over hydraulic fracturing and by suggesting a process to aid the debate and possibly other future controversies.
dc.format.mediumborn digital
dc.format.mediumdoctoral dissertations
dc.identifierT 7692
dc.identifier.urihttp://hdl.handle.net/11124/17048
dc.languageEnglish
dc.publisherColorado School of Mines. Arthur Lakes Library
dc.relation.ispartof2015 - Mines Theses & Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.subjectsynthetic aperture
dc.subjectpublic policy
dc.subjecthydraulic fracturing
dc.subjectelectromagnetics
dc.subjectCSEM
dc.subjectbeamforming
dc.subject.lcshProspecting -- Geophysical methods
dc.subject.lcshElectromagnetism
dc.subject.lcshSynthetic apertures
dc.subject.lcshBeamforming
dc.subject.lcshHydraulic fracturing -- Political aspects
dc.title3D synthetic aperture for controlled-source electromagnetics
dc.typeText
thesis.degree.disciplineGeophysics
thesis.degree.grantorColorado School of Mines
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy (Ph.D.)


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