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Now showing items 81-90 of 95

#### Approximate Effects of Off-Center Acoustic Sondes and Elliptic Boreholes Upon Full Waveform Logs

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1983)

Full waveform acoustic well logging has become instrumental to hydrocarbon exploration because of its ability to determine in situ velocity information for P and S waves as well as the attenuation (or absorption) of seismic ...

#### P And S Wave Velocity Determination

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1983)

There are three general methods that can be used to determine formation velocities from full waveform logs. The first approach is to make use of the data from the entire waveform. This type of velocity analysis is performed ...

#### A Numerical Investigation of Head Waves and Leaky Modes in Fluid-Filled Boreholes

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1985)

Although synthetic borehole seismograms routinely can be computed for a wide
range of borehole conditions, the physical nature of shear and compressional head
waves in fluid-filled boreholes is poorly understood. This ...

#### Full Wave Logging In An Irregular Borehole

(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 ...

#### Velocity Analysis of Multi-Receiver Full Waveform Acoustic Logging Data In Open and Cased Holes

(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 ...

#### Determination of Shear Wave Velocity and Attenuation From Waveforms in Low Velocity Formations

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)

In boreholes where formation shear velocity is lower than borehole fluid velocity neither refracted shear waves nor pseudo-Rayleigh waves can propagate. When frequency response of the sonde does not extend to low frequencies ...

#### Field Test of a Low-Frequency Sparker Source for Acoustic Waveform Logging

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)

Low-frequency acoustic-energy sources for waveform logging have important applications in: 1) Verifying theoretical calculations; 2) generating tube waves in large-diameter boreholes; and 3) providing larger sample volumes ...

#### Wave Propagation In A Fluid-Filled Fracture-An Experimental Study

(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, ...

#### Static Deformation of Fluid-Saturated Rocks

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1984)

The static strain response of porous solids to combinations of confining stress and pore pressure is explained both theoretically and experimentally. The theoretical analysis is a synopsis of linear elasticity principles ...

#### Tube Wave Attenuation and In-Situ Permeability

(Massachusetts Institute of Technology. Earth Resources Laboratory, 1985)

The measurement of in-situ permeability is very important in exploration and
production logging. Observed data show that tube wave attenuation in full waveform
acoustic logs is correlated with formation permeability. It ...