Now showing items 205-224 of 456

    • Frequency-Dependent Streaming Potentialsw 

      Reppert, Phillip M.; Morgan, Frank Dale; Lesmes, David P.; Jouniaux, Laurence (Massachusetts Institute of Technology. Earth Resources Laboratory, 2002)
      An experimental apparatus and data acquisition system was constructed to measure the streaming potential coupling coefficients as a function of frequency. The purpose of the experiments was to measure, for the first ...
    • Frequency-Domain Finite-Difference Acoustic Modeling with Free Surface Topography using Embedded Boundary Method 

      Li, Junlun; Zhang, Yang; Toksoz, M. Nafi (Massachusetts Institute of Technology. Earth Resources Laboratory, 2010)
      In this paper, we present a method to model acoustic wave propagation in the frequencydomain in the presence of free surface topography using the embedded boundary method. The advantage of this method is to solve for the ...
    • Frequency-Domain Modeling Techniques for the Scalar Wave Equation : An Introduction 

      Ajo-Franklin, Jonathan B. (Massachusetts Institute of Technology. Earth Resources Laboratory, 2005)
      Frequency-domain finite-difference (FDFD) modeling offers several advantages over traditional timedomain methods when simulating seismic wave propagation, including a convenient formulation within the context of wavefield ...
    • Full Wave Logging In An Irregular Borehole 

      Bouchon, Michel; Schmitt, Denis (Massachusetts Institute of Technology. Earth Resources Laboratory, 1988)
      We present a boundary integral equation formulation for the problem of wave propagation in a borehole of irregular cross-section. The method consists in representing the wave field diffracted at the borehole-rock interface ...
    • Full Wave Synthetic Acoustic Logs In Saturated Porous Media Part I: A Review Of Biot's Theory 

      Schmitt, D. P. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1986)
      Hydrocarbon exploration is especially concerned with two phase media. Following Biot, such finite porosity rocks are modeled as statistically isotropic materials composed of a solid elastic matrix permeated by a network ...
    • Full Wave Synthetic Acoustic Logs In Saturated Porous Media Part II: Simple Configuration 

      Schmitt, D. P. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1986)
      The discrete wavenumber method is used to compute synthetic full waveform acoustic logs in an axisymmetric fluid-filled borehole surrounded by a porous medium. The two phase formation is modeled following Biot's theory. ...
    • Full Wave Synthetic Acoustic Logs In Saturated Porous Media Part Ill: Pore Shape And Pore Geometry Effects 

      Schmitt, D. P. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1986-01-01)
      Homogenization theory states that the viscous and mass coupling coefficients of a fully saturated porous medium depend upon the pore shape and the pore geometry. Using an approximate formula, the three body wave velocities ...
    • The Full Waveform Acoustic Log Inversion Problem 

      Garcia, G. H.; Cheng, C. H. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1985)
      This paper presents the full waveform acoustic log inversion problem for a multisource - multireceiver tool logging a cylindrical fluid-filled borehole. The problem is formulated in the frequency-depth domain. A priori ...
    • Full Waveform Acoustic Logging - From Theory To Applications 

      Toksoz, M. N.; Cheng, C. H. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1985)
      This report contains results from the third year of the Full Waveform Acoustic Logging Consortium and rock physics studies at M.J.T. This year marks the completion of the first phase of the project which has been directed ...
    • Full Waveform Acoustic Logging - Where We Are, Where We Are Going 

      Toksoz, M. Nafi; Cheng, C. H.; Garcia, Gilles (Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)
      We have now completed the second year of the Full Waveform Acoustic Logging Consortium. During these two years, we have developed a good understanding of seismic wave propagation in a borehole through both theoretical ...
    • Full Waveform Inversion of P Waves for V[subscript s] and Q[subscript p] 

      Cheng, C. H. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1987)
      We present an indirect method of determining shear wave velocities from full waveform acoustic logs based on the inversion of the spectral ratio of the P-wave trains at two source-receiver separations. This method ...
    • Full-waveform Based Complete Moment Tensor Inversion and Stress Estimation from Downhole Microseismic Data for Hydrofracture Monitoring 

      Song, Fuxian; Toksoz, M. Nafi (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 ...
    • Full-waveform Based Microseismic Event Detection and Signal Enhancement: The Subspace Approach 

      Song, Fuxian; Warpinski, Norm R.; Toksoz, M. Nafi; Kuleli, Huseyin Sadi (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 ...
    • Full-waveform Based Microseismic Source Mechanism Studies in the Barnett Shale: Linking Microseismicity to Reservoir Geomechanics 

      Song, Fuxian; Warpinski, Norm R.; Toksoz, M. Nafi (Massachusetts Institute of Technology. Earth Resources Laboratory, 2013)
      Microseismic moment tensor (MT) contains important information on the reservoir and fracturing mechanisms. Difficulties arise when attempting to retrieve complete MT with conventional amplitude inversion methods if only ...
    • Geomechanical Modeling of In-Situ Stresses Around a Borehole 

      Grandi, Samantha; Rao, Rama V. N.; Toksoz, M. Nafi (Massachusetts Institute of Technology. Earth Resources Laboratory, 2002)
      In this paper, we present a modelling of the in-situ stress state associated with the severe hole enlargement of a wellbore. Geomechanical information is relevant to assure wellbore stability, i.e., to prevent damages ...
    • Geophysical Monitoring of Multiple Phase Saturation of Rocks: Application to CO[subscript 2] Sequestration 

      Brown, Stephen (Massachusetts Institute of Technology. Earth Resources Laboratory, 2011)
      4-D seismic techniques rely on measuring changes in velocity over time in order to detect changes during activities such as CO[subscript 2] flooding and storage in a reservoir. Wang et al. [1998] detail a laboratory study ...
    • Geophysical Well-Log Analysis In Characterizing The Hydrology Of Crystalline Rocks Of The Canadian Shield 

      Paillet, F . L. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1988)
      A full suite of geophysical logs, including nuclear, electric, acoustic transit-time, acoustic waveform, and acoustic televiewer logs, and high-resolution flowmeter measurements have been used to investigate the lithologic ...
    • Geostatistical Seismic Inversion Using Well Log Constraints 

      Kane, Jonathan; Rodi, William; Herrmann, Felix; Toksoz, M. Nafi (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 ...
    • Geostatistically Constrained Seismic Deconvolution 

      Kane, Jonathan; Al-Moqbel, Abdulrahman; Rodi, William; Toksoz, M. Nafi (Massachusetts Institute of Technology. Earth Resources Laboratory, 2002)
      We present a method for combining seismic deconvolution and geostatistical interpolation. Both problems are posed as a single joint inverse problem in the maximum likelihood framework. Joint inversion allows for well ...
    • Guided Waves In Slight, Azimuthally Anisotropic Formations 

      Ellefsen, K. J.; Cheng, C. H. (Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)
      A method of calculating dispersion curves for guided waves in slight, azimuthally anisotropic formations is developed with perturbation theory. The fluid is assumed to be inviscid, the formation perfectly elastic and ...