State of the art on EVA data processing: An improvement in subsurface imaging

Arditty, P.C.; Arens, Georges; Staron, Ph.

doi:10.1190/1.1826957

Cited by 5 publications

(1 citation statement)

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“…Comparisons of the two methods in the field have led to conflicting results. Arditty, Arens and Staron (1982) concluded that the risetime method gave more accurate results than the pulse spectral method, whilst Badri and Mooney (1987) came to the opposite conclusion. Figure 3 shows the principle of the pulse-echo technique.…”

Section: Pulse Risetime Methodsmentioning

confidence: 99%

GEOMETRIC CORRECTIONS IN ATTENUATION MEASUREMENTS¹

Klimentos

1991

Geophysical Prospecting

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KLIMENTOS, T. 1991. Geometric corrections in attenuation measurements. Geophysical Prospecting 39, 193-218. Seismic wave attenuation in porous rocks consists of intrinsic or anelastic attenuation (the lost energy is converted into heat due to interaction between the waves and the rocks) and the extrinsic or geometric attenuation (the energy is lost due to beam spreading, transmission loss and scattering). The first is of great importance because it can give additional information on the petrophysical properties of rocks (permeability, degree of saturation, type of saturant, etc.). The most difficult problem in attenuation measurements is estimating or eliminating extrinsic attenuation, so that the intrinsic attenuation can be obtained. To date, in laboratory attenuation measurements using wave propagation, several methods have been used. The difficulties vary with the method. The coupling effect and the geometric divergence or beam spreading are the major problems.Papadakis' diffraction corrections have been used extensively by Winkler and Plona in their modified pulse-echo high-pressure attenuation measurements. These corrections are computed for homogeneous liquid media and their failure to fit data for solid material implies that these corrections must be used with caution, especially for high Q values.Three new methods for laboratory ultrasonic attenuation measurements are presented.The first is the 'ultrasonic lens ' method for attenuation measurements at atmospheric pressure, in which an ultrasonic lens placed between transmitter and sample transforms the initially oblique incident beam into normal incidence so that the geometric divergence is eliminated. The second method is the 'panoramic receiver ', in which the beam spreading can be eliminated by integrating the ultrasonic energy over a large area. The third method is called ' self-spectral ratio ' and is applicable for all pressure conditions. Attenuation is estimated by comparing two signals recorded on the same rock but with two slightly different thicknesses under the same pressure conditions. Hence the extrinsic attenuation for both thicknesses is approximately the same. A comparison between the self-spectral ratio method and that of Winkler and Plona demonstrates a very good agreement for a broad band of frequencies. Hence the Winkler-Plona technique and Papadakis' diffraction corrections can be accepted as reliable in any future work.

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Section: Pulse Risetime Methodsmentioning

confidence: 99%

GEOMETRIC CORRECTIONS IN ATTENUATION MEASUREMENTS¹

Klimentos

1991

Geophysical Prospecting

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Slowness estimation from sonic logging waveforms

Kurkjian

Lang²,

Hsu

1991

Geoexploration

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A modeling study of borehole radar for oil‐field applications

Chen

Oristaglio²

2002

GEOPHYSICS

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This paper examines the suitability of borehole radar for near‐wellbore imaging. The maximum imaging range is primarily determined by the conductivity of the formation in which the borehole lies and the reflectivity of the targets. Under similar medium contrast, formation interfaces result in much stronger reflections than fractures. Complex horizontal borehole geometries are modeled with a 3‐D finite‐difference time‐domain (FDTD) code. Borehole effects, which are often almost insurmountable for acoustic methods, are very small for radar. As a result, the reflections in general are visually identifiable on the synthetic radar waveforms even before any signal processing. Therefore, borehole radar is a promising approach to map structures in the immediate vicinity of the borehole for a penetration depth of at least a few meters in relatively less‐conductive reservoirs (e.g., <0.03 S/m). As such, it complements borehole acoustic methods and has potential for geosteering applications.

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State of the art on EVA data processing: An improvement in subsurface imaging

Cited by 5 publications

References 1 publication

GEOMETRIC CORRECTIONS IN ATTENUATION MEASUREMENTS¹

GEOMETRIC CORRECTIONS IN ATTENUATION MEASUREMENTS¹

Slowness estimation from sonic logging waveforms

A modeling study of borehole radar for oil‐field applications

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State of the art on EVA data processing: An improvement in subsurface imaging

Cited by 5 publications

References 1 publication

GEOMETRIC CORRECTIONS IN ATTENUATION MEASUREMENTS1

GEOMETRIC CORRECTIONS IN ATTENUATION MEASUREMENTS1

Slowness estimation from sonic logging waveforms

A modeling study of borehole radar for oil‐field applications

Contact Info

Product

Resources

About

GEOMETRIC CORRECTIONS IN ATTENUATION MEASUREMENTS¹

GEOMETRIC CORRECTIONS IN ATTENUATION MEASUREMENTS¹