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The failure mode of correlation focusing for model velocity estimation
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)
We analyze the correlation focusing objective functional introduced by van Leeuwen and Mulder to avoid the cycle-skipping problem in full waveform inversion. While some encouraging numerical experiments were reported in ...
Seismic characterization of reservoirs with variable fracture spacing by double focusing Gaussian beams
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)
Fractured reservoirs account for a majority of the oil production worldwide and often have low recovery rate. Fracture characterization is important in building reservoir flow models for enhanced oil recovery. Information ...
Registration-guided least-squares waveform inversion
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2013-01-15)
Full waveform inversion with frequency sweeping cannot start from zero frequency because of the lack of low-frequency data, requiring a good starting model. We study a di fferent iterative scheme where the notion of proximity ...
Analysis of location uncertainty for a microearthquake cluster: A case study
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)
In many reservoirs, an increase in permeability and conductivity is achieved by hydraulic fracturing/stimulations which open cracks and fractures that then act as pathways for fluids to navigate in the subsurface. Mapping, ...
Joint microseismic event location with uncertain velocity
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)
We study the problem of the joint location of seismic events using an array of receivers. We show that locating multiple seismic events simultaneously is advantageous compared to the more traditional approaches of locating ...
Efficient characterization of uncertain model parameters with a reduced-order ensemble Kalman filter
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)
Spatially variable model parameters are often highly uncertain and di fficult to observe. This has prompted the widespread use of Bayesian characterization methods that can infer parameter values from measurements of related ...
A unified Bayesian framework for relative microseismic location
(Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)
We study the problem of determining an unknown microseismic event location relative to previously located events using a single monitoring array in a monitoring well. We show that using the available information about the ...
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 ...