Now showing items 434-453 of 456

    • Ultrasonic And Numerical Modeling Of Reflections From Simulated Fractured Reservoirs 

      Theophanis, Stephen; Zhu, Xiang (Massachusetts Institute of Technology. Earth Resources Laboratory, 1997)
      Vve examine seismic waves scattered from anisotropic heterogeneity with laboratory data and numerical modeling in order to develop modeling techniques for the characterization of fracture properties in tight gas sands ...
    • Ultrasonic Laboratory Study of Full Waveform Acoustic Logs in Boreholes with Fractures 

      Toksoz, M. N.; Guler, Fatih (Massachusetts Institute of Technology. Earth Resources Laboratory, 1987)
      A set of ultrasonic experiments was carried out to determine the effects of horizontal and vertical fractures on full waveform acoustic logs. Boreholes of 1 cm diameter were drilled in aluminum blocks. Measurements were ...
    • A unified Bayesian framework for relative microseismic location 

      Poliannikov, Oleg V.; Prange, Michael; Malcolm, Alison E.; Djikpesse, Hugues (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 ...
    • A unified framework for relative source localization using correlograms 

      Poliannikov, Oleg V.; Prange, Michael; Malcolm, Alison E.; Djikpesse, Hugues (Massachusetts Institute of Technology. Earth Resources Laboratory, 2012)
      We study the problem of determining an unknown 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 previously ...
    • Using Borehole Electroseismic Measurements To Detect And Characterize Fractured (Permeable) Zones 

      Mikhailov, Oleg V.; Queen, John H.; Toksoz, M. Nafi (Massachusetts Institute of Technology. Earth Resources Laboratory, 1997)
      We present a new type of field measurement capable of detecting and characterizing fractured (permeable) zones intersecting a borehole. The method is based on measuring electrical fields generated by a borehole Stoneley ...
    • Using Image Warping for Time-lapse Image Domain Wavefield Tomography 

      Yang, Di; Malcolm, Alison E.; Fehler, Michael (Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)
      Time-lapse seismic data are widely used for monitoring subsurface changes. A quantitative assessment of how reservoir properties have changed allows for better interpretation of fluid substitution and migration during ...
    • Using SVD for improved interferometric Green's function retrieval 

      Melo, Gabriela; Malcolm, Alison E.; Mikesell, Dylan; van Wijk, Kasper (Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)
      Seismic interferometry (SI) is a technique used to estimate the Green’s function (GF) between two receiver locations, as if there were a source at one of the receiver locations. However, in many applications, the requirements ...
    • Using SVD for improved interferometric Green’s function recovery. 

      Melo, Gabriela; Malcolm, Alison E.; Mikessel, Dylan; van Wijk, Kasper (Massachusetts Institute of Technology. Earth Resources Laboratory, 2010)
      Seismic interferometry is a technique used to estimate the Green’s function (GF) between two receiver locations, as if there were a source at one of the locations. By crosscorrelating the recorded seismic signals at the ...
    • Variable Grid Finite-Difference Modeling Including Surface Topography 

      Hayashi, Koichi; Burns, Daniel R. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1999)
      We have developed a two-dimensional viscoelastic finite-difference modeling method for highly complex topography. Realistic modeling of seismic wave propagation in the near surface is complicated by many factors, such ...
    • Velocity Analysis Of Multi-Receiver Full Waveform Acoustic Logging Data In Open And Cased Holes 

      Block, Lisa V.; Cheng, C. H.; Duckworth, Gregory L. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1986)
      Average semblance and maximum-likelihood spectral analysis are applied to synthetic full waveform acoustic logging data to determine formation velocities. Of particular interest is the ability of these methods to resolve ...
    • Velocity Analysis of Multi-Receiver Full Waveform Acoustic Logging Data In Open and Cased Holes 

      Block, Lisa V.; Cheng, C. H.; Duckworth, Gregory L. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1987)
      Average semblance and maximum-likelihood spectral analyses are applied to synthetic and field full waveform acoustic logging data to determine formation velocities. Of particular interest is the ability of these methods ...
    • Velocity Anisotropy Of Two Deep Crystalline Samples 

      Mendelson, Jim; Toksoz, M. N. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)
      Using ultrasonic velocity measurements taken over a multiplicity of directions we show that samples exhibit weak to moderate anisotropy of seismic velocities. We further define the anisotropic geometry with high resolution ...
    • Viscous Attenuation Of Acoustic Waves In Suspensions 

      Gibson, Richard L. Jr.; Toksoz, M. Nail (Massachusetts Institute of Technology. Earth Resources Laboratory, 1988)
      A model for attenuation of acoustic waves in suspensions is proposed which includes an energy loss due to viscous fluid flow around spherical particles. The expression for the complex wavenumber is developed by considering ...
    • Viscous Fluid Effects on Guided Wave Propagation in a Borehole 

      Burns, D. R. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1987)
      In order to investigate the effect of borehole fluid viscosity on the attenuation and dispersion of the guided waves present in full waveform acoustic logs, the problem of wave propagation in a borehole containing a ...
    • Viscous Fluid Effects on Guided Wave Propagation in a Borehole 

      Burns, D. R. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1987)
      In order to investigate the effect of borehole fluid viscosity on the attenuation and dispersion of the guided waves present in full waveform acoustic logs, the problem of wave propagation in a borehole containing a ...
    • Visibility Analysis using Reverse Time Wave Sensitivity for Time-Lapse Target-Oriented Imaging 

      Shabelansky, Andrey Hanan; Malcolm, Alison E.; Fehler, Michael (Massachusetts Institute of Technology. Earth Resources Laboratory, 2011)
      Identifying the relationship between surface seismic data and a particular region in the earth, referred to as visibility analysis, is important because it facilitates the optimization of the quality and speed of the imaging ...
    • Wave Propagation In A Fluid-Filled Fracture-An Experimental Study 

      Tang, X. M.; Cheng, C. H. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)
      A laboratory experimental study has been carried out to investigate the mode trapping characteristics of a fluid-filled fracture between two elastic solids. Using a small circular cylindrical receiver of 2.7 mm diameter, ...
    • Wave-Equation Reflection Tomography: Annihilators and Sensitivity Kernals 

      van der Hilst, Robert D.; de Hoop, Maarten V.; Shen, Peng (Massachusetts Institute of Technology. Earth Resources Laboratory, 2007)
      In seismic tomography, the finite frequency content of broad-band data leads to interference effects in the process of medium reconstruction, which are ignored in traditional ray theoretical implementations. Various ways ...
    • Wavelet Domain Geophysical Inversion 

      Kane, Jonathan; Herrmann, Felix; Toksoz, M. Nafi (Massachusetts Institute of Technology. Earth Resources Laboratory, 2002)
      We present a non-linear method for solving linear inverse problems by thresholding coefficients in the wavelet domain1. Our method is based on the wavelet-vaguelette decomposition of Donoho (1992). Numerical results for ...
    • Wavelet domain linear inversion with application to well logging 

      Kane, Jonathan; Herrmann, Felix; Toksoz, M. Nafi (Massachusetts Institute of Technology. Earth Resources Laboratory, 2001)
      Solving linear inversion problems in geophysics is a major challenge when dealing with non-stationary data. Certain non-stationary data sets can be shown to lie in Besov function spaces and are characterized by their ...