Browsing McMechan, George A. by Title
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2d FrequencyDomain Elastic FullWaveform Inversion Using TimeDomain Modeling and a MultistepLength Gradient Approach
(Soc Exploration Geophysicists, 20140217)To decouple the parameters in elastic fullwaveform inversion (FWI), we evaluated a new multisteplength gradient approach to assign individual weights separately for each parameter gradient and search for an optimal step ... 
3D, 9C Seismic Modeling and Inversion of Weyburn Field Data
(20120618)Inversion of 3D, 9C wide azimuth vertical seismic profiling (VSP) data from the Weyburn Field for 21 independent elastic tensor elements was performed based on the Christoffel equation, using slowness and polarization ... 
AVA Analysis and Interpretation of a Carbonate Reservoir: Northwest Java Basin, Indonesia
A detailed analysis is performed of amplitude variation with angle (AVA) observations in six commonmidpoint gathers with reflection points that are over and beside carbonate reefs in the Parigi Formation in the northwest ... 
Characterization of a Coalesced, Collapsed Paleocave Reservoir Analog Using GPR and WellCore Data
(Society of Exploration Geophysicists, 200207)The threedimensional architecture, spatial complexity, and poretype distribution are mapped in a nearsurface analog of a coalesced, collapsed paleocave system in the Lower Ordovician Ellenburger Group near the city of ... 
Combining Multidirectional Source Vector with AntitruncationArtifact Fourier Transform to Calculate Angle Gathers from Reverse Time Migration in Two Steps
(Society of Exploration Geophysicists, 20170811)Because receiver wavefields reconstructed from observed data are not as stable as synthetic source wavefields, the sourcepropagation vector and the reflector normal have often been used to calculate angledomain commonimage ... 
CommonReflectionPoint Migration Velocity Analysis of 2D PWave Data From TTI Media
(Soc Exploration Geophysicists, 201405)We have developed a commonreflectionpoint (CRP)based kinematic migration velocity analysis for 2D Pwave reflection data to estimate the four transversely isotropic (TI) parameters VPo, δ, and ε, and the tilt angle ϕ ... 
Comparison of Methods for Extracting ADCIGS from RTM
(Soc Exploration Geophysicists, 20140401)Methods for extracting angledomain commonimage gathers (ADCIGs) during 2D reversetime migration fall into three main categories; directionvectorbased methods, localplanewave decomposition methods, and localshift ... 
Comparison of Two Algorithms for Isotropic Elastic P and S Vector Decomposition
(Society of Exploration Geophysicists, 20150610)P and Swavefield separation is necessary to extract PP and PS images from prestack elastic reverse time migrations. Unlike traditional separation methods that use curl and divergence operators, which do not preserve the ... 
Conductivity and Scattering Q in GPR Data: Example from the Ellenburger Dolomite, Central Texas
(20120627)Total attenuation (Qt 1) in groundpenetrating radar (GPR) data is a composite of intrinsic and scattering attenuations (Qin 1 and Qsc 1). For nonmagnetic materials, Qin 1 is a combination of the effects of real ... 
Efficient Love Wave Modelling via Sobolev Gradient Steepest Descent
(Oxford University Press, 20160222)A new method for finding solutions to ordinary differential equation boundary value problems is introduced, in which Sobolev gradient steepest descent is used to determine eigenfunctions and eigenvalues simultaneously in ... 
Estimation of Gas Hydrate and Free Gas Saturation, Concentration, and Distribution from Seismic Data
(Society of Exploration Geophysicists, 20180824)Gas hydrates contain a major untapped source of energy and are of potential economic importance. The theoretical models to estimate gas hydrate saturation from seismic data predict significantly different acoustic/ elastic ... 
Gas hydrate and free gas petroleum system in 3D seismic data, offshore Angola
(Society of Exploration Geophysicists, 20120926)Evidence of gas hydrate and free gas occurrences in a 3D seismic volume from the WestCentral Coastal Province of the Congo Fan, offshore Angola, illustrates all the components of a complete petroleum system. Analysis and ... 
P and SDecomposition in Anisotropic Media with Localized LowRank Approximations
(Society of Exploration Geophysicists, 20171113)We have developed a P and Swave decomposition algorithm based on windowed Fourier transforms and a localized lowrank approximation with improved scalability and efficiency for anisotropic wavefields. The model and ... 
Removing SmearingEffect Artifacts in AngleDomain CommonImage Gathers from Reverse Time Migration
(Soc Exploration Geophysicists, 20150317)Local planewave decomposition (LPWD) and local shift imaging condition (LSIC) methods for extracting angledomain commonimage gathers (ADCIGs) from prestack reverse time migration are based on the local planewave ... 
Reverse Time Migrations in Transversely Isotropic Media: A Comparison between Acoustic and Elastic Wave Equations with Two Wave Mode Separation Algorithms
Anisotropic reverse time migrations (RTMs) using pseudoacoustic or elastic wave equations are tested, and the migrated PP images, obtained using the same data set as input, are compared. In anisotropic elastic RTMs, both ... 
Sensitivity of Estimated Elastic Moduli to Completeness of Wave Type, Measurement Type, and Illumination Apertures at a Receiver in Multicomponent VSP Data
(20120201)Inversion of phase slowness and polarization vectors measured from multicomponent vertical seismic profile data can yield estimates of all 21 densitynormalized elastic moduli for anisotropic elastic media in the neighborhood ... 
TimeDomain LeastSquares Migration Using the Gaussian Beam Summation Method
With a finite recording aperture, a limited source spectrum and unbalanced illumination, traditional imaging methods are insufficient to generate satisfactory depth profiles with high resolution and high amplitude fidelity. ... 
Tomography of DiffractionBased Focusing Operators
(20120824)Diffractions carry the same kinematic information provided by common focus point operators (CFPOs). Thus CFPO and diffraction time trajectories may be used separately, or combined into a single unified tomography for ... 
Up/Down and P/S Decompositions of Elastic Wavefields Using Complex Seismic Traces with Applications to Calculating Poynting Vectors and AngleDomain CommonImage Gathers from Reverse Time Migrations
(Society of Exploration Geophysicists, 20180601)Separations of up and downgoing as well as of P and Swaves are often a part of processing of multicomponent recorded data and propagating wavefields. Most previous methods for separating up/down propagating wavefields ... 
VectorBased Elastic Reverse Time Migration
(Society of Exploration Geophysicists, 20151015)Prestack elastic reverse time migration (RTM) of multicomponent seismic data requires separating PP and PS reflections before, or as part of, applying the image condition, and using image conditions that preserve the angle ...