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Natural fracture characterization using passive seismic illumination

Description: The presence of natural fractures in reservoir rock can significantly enhance gas production, especially in tight gas formations. Any general knowledge of the existence, location, orientation, spatial density, and connectivity of natural fractures, as well as general reservoir structure, that can be obtained prior to active seismic acquisition and drilling can be exploited to identify key areas for subsequent higher resolution active seismic imaging. Current practices for estimating fracture pr… more
Date: January 8, 2003
Creator: Nihei, K.T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Nonlinear interaction of plane elastic waves

Description: The paper presents basic first order results of nonlinear elastic theory by Murnaghan for elastic wave propagation in isotropic solids. The authors especially address the problem of resonant scattering of two collimated beams and present analytical solutions for amplitudes of all possible types of resonant interactions for elastic plane waves. For estimation of nonlinear scattered waves they use measured elastic parameters for sandstone. The most profound nonlinear effect is expected for intera… more
Date: June 1, 1998
Creator: Korneev, V.A.; Nihei, K.T. & Myer, L.R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Fracture imaging with converted elastic waves

Description: This paper examines the seismic signatures of discrete, finite-length fractures, and outlines an approach for elastic, prestack reverse-time imaging of discrete fractures. The results of this study highlight the importance of incorporating fracture-generated P-S converted waves into the imaging method, and presents an alternate imaging condition that can be used in elastic reverse-time imaging when a direct wave is recorded (e.g., for crosswell and VSP acquisition geometries).
Date: May 29, 2001
Creator: Nihei, K.T.; Nakagawa, S. & Myer, L.R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Phased array compaction cell for measurement of the transversely isotropic elastic properties of compacting sediments

Description: Sediments undergoing compaction typically exhibit transversely isotropic (TI) elastic properties. We present a new experimental apparatus, the phased array compaction cell, for measuring the TI elastic properties of clay-rich sediments during compaction. This apparatus uses matched sets of P- and S-wave ultrasonic transducers located along the sides of the sample and an ultrasonic P-wave phased array source, together with a miniature P-wave receiver on the top and bottom ends of the sample. The… more
Date: December 15, 2010
Creator: Nihei, K.T.; Nakagawa, S.; Reverdy, F.; Meyer, L.R.; Duranti, L. & Ball, G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Characterization of fracture networks for fluid flow analysis

Description: The analysis of fluid flow through fractured rocks is difficult because the only way to assign hydraulic parameters to fractures is to perform hydraulic tests. However, the interpretation of such tests, or ''inversion'' of the data, requires at least that we know the geometric pattern formed by the fractures. Combining a statistical approach with geophysical data may be extremely helpful in defining the fracture geometry. Cross-hole geophysics, either seismic or radar, can provide tomograms whi… more
Date: June 1, 1989
Creator: Long, J. C. S.; Billaux, D.; Hestir, K.; Majer, E. L.; Peterson, J.; Karasaki, K. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Extensional wave attenuation and velocity in partially saturated sand in the sonic frequency range

Description: Extensional wave attenuation and velocity measurements on a high permeability Monterey sand were performed over a range of gas saturations for imbibition and degassing conditions. These measurements were conducted using extensional wave pulse propagation and resonance over a 1-9 kHz frequency range for a hydrostatic confining pressure of 8.3 MPa. Analysis of the extensional wave data and the corresponding X-ray CT images of the gas saturation show strong attenuation resulting from the presence … more
Date: August 10, 2001
Creator: Liu, Z.; Rector, J. W.; Nihei, K. T.; Tomutsa, L.; Myer, L. R. & Nakagawa, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effects of heterogeneity and friction on the deformation and strength of rock

Description: Experimental observations of the evolution of damage in rocks during compressive loading indicate that macroscopic failure occurs predominantly by extensile crack growth parallel or subparallel to the maximum principal stress. Extensile microcracks initiate at grain boundaries and open pores by a variety of micromechanical processes which may include grain bending, Brazilian type fracture and grain boundary sliding. Microstructural heterogeneity in grain size, strength and shape determines the … more
Date: March 1, 1994
Creator: Nihei, K. T.; Myer, L. R.; Liu, Z.; Cook, N. G. W. & Kemeny, J. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Extensional wave attenuation and velocity in partially-saturated sand in the sonic frequency range

Description: Extensional wave attenuation and velocity measurements on a high permeability Monterey sand were performed over a range of gas saturations for imbibition and degassing conditions. These measurements were conducted using extensional wave pulse propagation and resonance over a 1 - 9 kHz frequency range for a hydrostatic confining pressure of 8.3 MPa. Analysis of the extensional wave data and the corresponding X-ray CT images of the gas saturation show strong attenuation resulting from the presenc… more
Date: June 17, 2002
Creator: Liu, Z.; Rector, J. W.; Nihei, K. T.; Tomutsa, L.; Myer, L. R. & Nakagawa, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

San Juan Fracture Characterization Project: Status and current results

Description: The overall objectives of this report are to extend current state-of-the-art 3-D imaging to extract the optimal information for fracture quantification and to develop next generation capability in fracture imaging for true 3-D imaging of the static and dynamic fracture properties.
Date: February 26, 2001
Creator: Majer, E. L.; Daley, T. M.; Myer, L. R.; Nihei, K.; Queen, J.; Sinton, J. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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