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Now showing items 1-10 of 13

#### Applications Of Perturbation Theory To Acoustic Logging

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)

For guided wave propagation in boreholes, perturbation theory is used to calculate
(1) the partial derivative of the wavenumber or frequency with respect to an elastic
modulus or density, (2) group velocity, and (3) the ...

#### Report Summary

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)

This report contains the results of work completed during the seventh year of the
Full Waveform Acoustic Logging Consortium in the Earth Resources Laboratory at
M.LT. During the past year, we have been concentrating on ...

#### Permeability Estimation From Velocity Anisotropy In Fractured Rock

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)

Cracks in a rock mass subjected to a uniaxial stress will be preferentially closed depending on the angle between the fracture normal and the direction of the applied
stress. If the prestress fracture distribution is ...

#### Multi-Shot Processing For Better Velocity Determination

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)

We perform a technique called multi-shot processing on a section of 12-channel sonic
logs in order to better resolve compressional and shear velocities. The data are from
the ODP Leg 102 cruise, which occupied drill site ...

#### Theoretical Models Relating Acoustic Tube-Wave Attenuation To Fracture Permeability - Reconciling Model Results With Field Data

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)

Several recent investigations indicate that tube-wave amplitude attenuation in acoustic
full-waveform logs is correlated with permeability in fractured rocks. However, there
are significant differences between predictions ...

#### Pore Geometry And Permeability Modeling From Pressure Dependence Of Transport Properties In Sandstone

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)

In this paper, a model of the pore geometry of sandstones is proposed. Three categories
of pores are considered: large spherical pores at 4-grain vertices, tube-like throats at
3-grain edges and narrow sheet-like throats ...

#### Stoneley Wave Propagation In A Fluid-Filled Borehole With A Vertical Fracture

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)

The propagation of Stoneley waves in a fluid-filled borehole with a vertical fracture is
investigated both theoretically and experimentally. The borehole propagation excites
fluid motion in the fracture and the resulting ...

#### Estimating The Elastic Moduli Of Transversely Isotropic Formations

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)

Using acoustic logging data, we develop a method of estimating the horizontal shear
modulus C[subscript 66]) of a transversely isotropic formation with its axis of symmetry parallel to that of the borehole. The data for ...

#### Evaluation And Prediction Of Shear Wave Velocities In Soft Marine Sediments

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)

Shear wave velocities from full waveform acoustic logs were determined at DSDP Site
613 using the spectral ratio inversion method. Discrete shear wave velocities for a 350
meter interval at 0.5-2 meter depth increments ...

#### Multi-Shot Processing For Better Velocity Determination

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1989)

We develop a linear programming inversion scheme to estimate lithology from well log
data. The inversion described severely limits the dependence on core retrieval, and
makes accurate mapping of new parameters possible. ...