Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 32 for “"Velocity analysis"”.
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Velocity analysis in the presence of uncertainty
Velocity analysis resolves relatively long scales of earth structure, on the order of 1 km. Migration produces images with length scales (wavelengths) on the order of 10's of m. In between these two scale regimes lies another, corresponding roughly to structures between 60 to 300m in extent, in …
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Velocity analysis for laterally heterogeneous anisotropic media
Includes bibliographical references (pages 144-151).
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HRVA - a velocity analysis technique for seismic data
"A High-Resolution Velocity Analysis (HRVA) has been developed for the determination of the root-mean-square subsurface-velocity energy spectrum from gated seismic data which has been normal-moveout corrected. All calculations are performed in the frequency-space or frequency-wavenumber domain; …
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Kirchhoff Common Offset Migration Velocity Analysis via Differential Semblance
… and fast approach to obtain an accurate velocity model for seismic imaging. An accurate velocity model is prerequisite for obtaining the image that represents the true underground geological structure: major evidence to explore for potential reservoirs and indicate hydrocarbons. This …
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Joint migration velocity analysis of PP- and PS-waves for VTI media
… with mode-converted PS reflections in migration velocity analysis can help build more accurate VTI velocity models. To avoid problems caused by the moveout asymmetry of PS-waves and take advantage of efficient MVA algorithms designed for pure modes, I suggest to generate pure SS-reflections from …
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Comparison of edge turbulence velocity analysis techniques using Gas Puff Imaging data on Alcator C-Mod
… been used. One uses temporal and spatial Fourier analysis to obtain wavenumber-frequency spectra, from which a phase velocity is computed [1, 2]. The other is based on time-delay cross-correlation of successive images used to track the motion of discrete emission structures [3, 4]. Several …
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Theory and application of source independent full wavefield elastic converted phase seismic imaging and velocity analysis
… source of uncertainty in seismic imaging and velocity analysis applications. In this thesis, we develop source-independent methods for seismic imaging, seismic trace interpolation and velocity analysis using the interference between pure (PP and SS) and converted-phase (PS and SP) waves. For …
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Anisotropic media and the determination of subsurface velocity by the use of surface seismic reflection data
Velocity anisotropy is present at a point in a medium if the seismic velocity in one direction in general differs from that in another direction. The problems associated with the determination of subsurface velocity in anisotropic media by the use of surface seismic reflection data are analyzed. …
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Building Velocity Models for Steep-Dip Prestack Depth Migration through First Arrival Traveltime Tomography
… depth migration, and an excellent seismic velocity model. Poststack time migrated seismic images, normal moveout velocity analysis, well logs, and other geologic information are used to build the velocity model. In regions of interest outside of sedimentary basins, such as major strike-slip …
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Ps receiver function imaging of crustal structure and Moho topography beneath the Northeast Caribbean.
… distribution in the region. To calculate a velocity model for migration, we implement a technique analogous to "velocity analysis" in reflection seismology. We image a strong positive amplitude feature that shallows from ~40 km in the west to ~30 km in the east, which we interpret as the …
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Seismic Imaging and Velocity Model Building in the Thrace Region, Northwestern Turkey: A Case Study
… refine the velocities to get the final interval velocity. Having the final interval velocity, reverse-time migration was used. The tomographic velocity analysis was successful in yielding an accurate interval velocity. After application of all these imaging methods, I found that the RTM gave the …
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Aerocapture guidance methods for high energy trajectories
… by boundaries based on percentage of forward velocity. Analysis of the resulting entry corridor revealed that the enhanced algorithm generated a mean improvement of 261% over the PredGuid corridor. Most of the gain occurred for steeper flight path angles. Results also indicated that the …
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Single-cell differential splicing of Alzheimer’s Disease in 1.9 million cells across 416 individuals
… steady-state cell behavior. By contrast, RNA velocity analysis allows inference of both direction and magnitude of regulatory changes occuring over disease progression. However, despite the success of existing RNA velocity analyses, the pace of disease progression remains uncharacterized, as …
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Processing Case Study with AVO and Pore Pressure Analyses: Eugene Island, Gulf of Mexico
… the processed seismic image with pore pressure analysis, petrophysical analysis and calibrated seismic attributes derived from the petrophysical analysis indicates the area would be classified as a Class III AVO environment which is supported by the geologic background. The dataset is further …
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Wake Filling Techniques for Reducing Rotor-Stator Interaction Noise
… was performed for flow visualizations as well as velocity analysis in the wake region.
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Investigating Mesoscale, Submesoscale, and Mixing Ocean Dynamics in the Mozambique Channel Using Seismic and Simulation Datasets
… wave removal, and f-k filtering, followed by velocity analysis, amplitude correction, stacking and deconvolution. Detailed images of phenomena including anticyclonic and cyclonic eddy distortions, submesoscale lenslike structures, and water mass boundary are presented. A combined inversion was …
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Stress prediction, fracture detection, and multiple attribute analysis of seismic attributes in a Barnett Shale gas reservoir, Fort Worth Basin, Texas
… and natural fractures. Azimuthal interval velocity analysis was found to be an effective tool for the detection of changing stress fields. The analysis of azimuthal amplitude data suggests that it can be used to map changes in azimuthal anisotropy with higher spatial resolution than …
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The Effects of Bisphosphonates on Bone Remodeling: Analysis of Microdamage Targeting by BMUs, BMU Velocity and Crack Surface Density
… that bisphosphonates would decrease BMU velocity and osteonal area while increasing crack surface density in a dose-dependent manner. Thirty-six rib bone samples were obtained from the Indiana University School of Medicine from a three year canine study in which skeletally mature beagles …
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Enhanced imaging of deep lithospheric and shallow near surface structures through innovations in seismic interferometry and array processing.
… deep upper mantle. The first study uses array analysis of ambient noise autocorrelograms recorded by a dense nodal array near Sweetwater, Texas to image P-wave reflectivity of the upper mantle. A coherent reflection event at approximately 26 seconds two-way time is detected consistently across …
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Studies of Turbulent Round Jets Through Experimentation, Simulation, and Modeling
… particles from a glass surface. Theoretical analysis revealed trends and enabled modeling to improve the predictability of particle removal for various jet conditions. The second part of thesis aims at developing a non-intrusive measurement technique for free-shear turbulent flows in nature. …
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