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Carbon sequestration monitoring with acoustic double-difference waveform inversion: A case study on SACROC walkaway VSP data
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2011)
Geological carbon sequestration involves large-scale injection of carbon dioxide into underground geologic formations and is considered as a potential approach for mitigating global warming. Changes in reservoir properties ...
Approximate inversion of the wave-equation Hessian via randomized matrix probing
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2012)
We present a method for approximately inverting the Hessian of full waveform inversion as a dip-dependent and scale-dependent amplitude correction. The terms in the expansion of this correction are determined by least-squares ...
Full-waveform Based Complete Moment Tensor Inversion and Stress Estimation from Downhole Microseismic Data for Hydrofracture Monitoring
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2011)
Downhole microseismics has gained increasing popularity in recent years as a way to characterize hydraulic fracturing and to estimate in-situ stress state. Conventional approaches only utilize part of the information ...
Double-beam stacking to infer seismic properties of fractured reservoirs
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2011)
We develop a theory for using 3D beam interference to infer scattering properties of a fractured reservoir using reflected seismic P data. For the sake of simplicity, we use Gaussian beams. The scattering properties are ...
Geostatistical Seismic Inversion Using Well Log Constraints
(Massachusetts Institute of Technology. Earth Resources Laboratory, 1999)
Information about reservoir properties usually comes from two sources: seismic data
and well logs. The former provide an indirect, low resolution image of rock velocity
and density. The latter provide direct, high ...
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 ...
An approach for predicting stress-induced anisotropy around a borehole
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2012)
Formation elastic properties near a borehole may be altered from their original state due to the stress concentration around the borehole. This could result in a biased estimation of formation properties but could provide ...
Efficient Double-Beam Characterization for Fractured Reservoir
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2012-06)
We proposed an efficient target-oriented method to characterize seismic properties of fractured reservoirs: the spacing between fractures and the fracture orientation. Based on the diffraction theory, the scattered wave ...
Full-waveform Based Microseismic Event Detection and Signal Enhancement: The Subspace Approach
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)
Microseismic monitoring has proven to be an invaluable tool for optimizing hydraulic fracturing stimulations and monitoring reservoir changes. The signal to noise ratio (SNR) of the recorded microseismic data varies ...
Estimating the fracture density of small-scale vertical fractures when large-scale vertical fractures are present
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)
When fractures are vertical, aligned and their dimensions are small relative to the seismic wavelength, the medium can be considered to be an equivalent Horizontal Transverse Isotropic (HTI) medium. However, geophysical ...