Browsing Earth Resources Laboratory by Title
Now showing items 288-307 of 456
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Multifractional splines: from seismic singularities to geological transitions
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2002)A matching pursuit technique in conjunction with an imaging method is used to obtain quantitative information on geological records from seismic data. The technique is based on a greedy, non-linear search algorithm ... -
Multiple aperture INSAR (MAI) with C-band and L-band data: Noise and precision
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2012)MAI is a technique to extract along-track (horizontal) phase-based displacements from InSAR data. MAI’s theoretical precision can be at the centimeter level, an order of magnitude improvement over amplitude-based pixel ... -
Multiple Multipole Expansions For Elastic Scattering: An Aid To Understanding The Problems In "No-Record" Areas
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1996)This paper presents a new approach to solving scattering of elastic waves in two dimensions. Wavefields are often expanded into an orthogonal set of basis functions. Unfortunately, these expansions converge rather slowly ... -
Multipole seismoelectric logging while drilling (LWD) for acoustic velocity measurements
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2012)In seismoelectric well logging, an acoustic wave propagates along a borehole and induces electrical signals along the borehole wall. The apparent velocities of these seismoelectric signals are equal to the formation ... -
Multiscale Determination of In Situ Stress and Fracture Properties in Reservoirs
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2008-02)In this thesis we address the problem of determining in situ stress and fracture properties in reservoirs using borehole logs and surface seismic reflection data. The dissertation covers four subtopics. The first is the ... -
Near-Surface Scattering From High Velocity Carbonates In West Texas
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1998)Seismic data acquired directly over near-surface limestone formations are commonly observed to be of inferior quality. A possible cause for this degradation is scattering in the near-subsurface by, e.g., the weathering ... -
New Applications In The Inversion Of Acoustic Full Waveform Logs - Relating Mode Excitation To Lithology
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1986-01-01)Existing techniques for the quantitative interpretation of waveform data have been based on one of two fundamental approaches: 1) simultaneous identification of compressional and shear wave velocities; and 2) least-squares ... -
Non-Linear Constraints with Application to Self-Potential Source Inversion
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2006-05)We investigate the use of non-linear constraints for geophysical inverse problems, with specific examples applied to source inversion of self-potential data. Typical regularization methods often produce smooth solutions ... -
Nonhyperbolic Reflection Moveout For Azimuthally Anisotropic Media
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1999)Reflection moveout in azimuthally anisotropic media is not only azimuthally dependent but it is also nonhyperbolic. As a result, the conventional hyperbolic normal moveout (NMO) equation parameterized by the exact NMO ... -
Nonhyperbolic reflection moveout for orthorhombic media
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2002)Reflection moveout in azimuthally anisotropic media is not only azimuthally dependent but it is also nonhyperbolic. As a result, the conventional hyperbolic normal moveout (NMO) equation parameterized by the exact NMO ... -
Nonlinear Conjugate Gradients Algorithm For 2-D Magnetotelluric Inversion
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2000)We investigate a new algorithm for computing regularized solutions of the two-dimensional magnetotelluric inverse problem. The algorithm employs a nonlinear conjugate gradients (NLCG) scheme to minimize an objective ... -
Nonlinear Frechet derivative and its De Wolf approximation
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2012)We introduce and derive the nonlinear Frechet derivative for the acoustic wave equation. It turns out that the high order Frechet derivatives can be realized by consecutive applications of the scattering operator and a ... -
Nonlinear Refraction Traveltime Tomography
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1996)We identify a few unique issues that are important for performing a nonlinear refraction traveltime tomography effectively. These include accuracy of traveltime and raypath calculation for a turning ray and physical ... -
Nonlinear Semblance Processing For The Evaluation Of An Acoustic Altered Zone Around The Borehole
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1994)This paper describes a simple method to evaluate an acoustic altered zone around the borehole using an array of sonic waveforms. The method is based on a semblance velocity analysis and a nonlinear travel time window is ... -
Nonlinear Soil Response in the Near-Field of a Vibrator Truck: Application to Land Seismic Surveys
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2007)The nonlinear behavior of soils can significantly modify the wavelet radiated from vibrator trucks. In this paper, we describe a field experiment designed to measure the nonlinear response of a natural soil formation in ... -
A Novel Application of Time Reversed Acoustics: Salt Dome Flank Imaging Using Walk Away VSP Surveys
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2005)In the past few years, there has been considerable research and interest in a topic known by various names, such as Time Reverse Acoustics (TRA), Time Reverse Mirrors (TRM), and Time Reverse Cavities (TRC), which exploits ... -
A Novel Application of Time Reversed Acoustics: Salt Dome Flank Imaging Using Walkaway VSP surveys
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2006-03-01)In this paper we present initial results of applying Time-Reversed Acoustics (TRA) technology to saltdome flank, seismic imaging. We created a set of synthetic traces representing a multilevel, walkaway VSP for a model ... -
Nullerical Studies of Body Wave Amplitudes in Full Waveform Acoustic Logs
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)The amplitudes of P and S head waves in a full waveform acoustic log microseismogram are studied numerically as a function of borehole and formation parameters. The technique used is contour integration around the respective ... -
A Numerical Investigation of Head Waves and Leaky Modes in Fluid-Filled Boreholes
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1985)Although synthetic borehole seismograms routinely can be computed for a wide range of borehole conditions, the physical nature of shear and compressional head waves in fluid-filled boreholes is poorly understood. This ... -
Numerical modeling of elastic wave scattering by near-surface heterogeneities
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)A perturbation method for elastic waves and numerical forward modeling are used to calculate the effects of seismic wave scattering from arbitrary shape shallow subsurface heterogeneities. Wave propagation is simulated ...
