Negative bottom loss, critical‐angle shift, and the interpretation of the bottom reflection coefficient

1977 ◽  
Vol 61 (3) ◽  
pp. 707-710 ◽  
Author(s):  
D. C. Stickler
Keyword(s):  
Reflection Coefficient ◽  
Critical Angle ◽  
Angle Shift

Linearized amplitude variation with offset (AVO) inversion with supercritical angles

Geophysics ◽  
2006 ◽  
Vol 71 (5) ◽  
pp. E49-E55 ◽  
Author(s):  
Jonathan E. Downton ◽  
Charles Ursenbach
Keyword(s):  
Reflection Coefficient ◽  
Critical Angle ◽  
Waveform Inversion ◽  
Phase Variation ◽  
Reflection Coefficients ◽  
Amplitude Variation ◽  
Amplitude Variation With Offset ◽  
Zoeppritz Equations ◽  
Avo Inversion ◽  
Angle Data

Contrary to popular belief, a linearized approximation of the Zoeppritz equations may be used to estimate the reflection coefficient for angles of incidence up to and beyond the critical angle. These supercritical reflection coefficients are complex, implying a phase variation with offset in addition to amplitude variation with offset (AVO). This linearized approximation is then used as the basis for an AVO waveform inversion. By incorporating this new approximation, wider offset and angle data may be incorporated in the AVO inversion, helping to stabilize the problem and leading to more accurate estimates of reflectivity, including density reflectivity.

Influence of Lateral Shift on Normal Moveout of SH-Wave

2013 ◽  
Vol 838-841 ◽  
pp. 1530-1533
Author(s):  
An Ling Wang ◽  
Fu Ping Liu
Keyword(s):  
Reflection Coefficient ◽  
Data Processing ◽  
Error Correction ◽  
Seismic Data ◽  
Critical Angle ◽  
Large Error ◽  
Lateral Shift ◽  
Angle Of Incidence ◽  
Seismic Data Processing ◽  
Sh Wave

Using the lateral shift and shift time of reflection coefficient of SH seismic wave at the interface of strata, , we derived and given formulae of normal moveout of lateral shift, discussed the influence of lateral shift on normal moveout of SH-wave, and drawn the curves of normal moveout of lateral shift and the error of normal moveout caused by lateral shift with respect to the angle of incidence. The results show that for glancing wave or angle of incidence being near the critical angle, A large error can be caused by t lateral shift; The error correction of lateral shift should be done before seismic data processing.

The Shift Time of Reflection Sh-Wave on an Interface of Two Media

2014 ◽  
Vol 488-489 ◽  
pp. 870-872
Author(s):  
An Ling Wang ◽  
Fu Ping Liu
Keyword(s):  
Phase Shift ◽  
Reflection Coefficient ◽  
Seismic Wave ◽  
Critical Angle ◽  
Angle Of Incidence ◽  
Sh Wave ◽  
Large Shift ◽  
Order Of Magnitude

Using the phase shift of reflection coefficient of SH seismic wave at the interface of strata, we derived the shift time of total reflected SH-wave, given formulae of shift time,The results show that for glancing wave or angle of incidence being near the critical angle, the shift time are very large. A large shift can be caused,In other angle of incidence the shift time is the same order of magnitude as the wavelength (period).

A simplification of the Zoeppritz equations

Geophysics ◽  
1985 ◽  
Vol 50 (4) ◽  
pp. 609-614 ◽  
Author(s):  
R. T. Shuey
Keyword(s):  
Reflection Coefficient ◽  
Elastic Properties ◽  
Critical Angle ◽  
Wave Reflection ◽  
Normal Incidence ◽  
Compressional Wave ◽  
Zoeppritz Equations ◽  
The Third ◽  
Reflection Data ◽  
Simplified Formula

The compressional wave reflection coefficient R(θ) given by the Zoeppritz equations is simplified to the following: [Formula: see text] The first term gives the amplitude at normal incidence (θ = 0), the second term characterizes R(θ) at intermediate angles, and the third term describes the approach to critical angle. The coefficient of the second term is that combination of elastic properties which can be determined by analyzing the offset dependence of event amplitude in conventional multichannel reflection data. If the event amplitude is normalized to its value for normal incidence, then the quantity determined is [Formula: see text] [Formula: see text] specifies the normal, gradual decrease of amplitude with offset; its value is constrained well enough that the main information conveyed is [Formula: see text] where [Formula: see text] is the contrast in Poisson’s ratio at the reflecting interface and [Formula: see text] is the amplitude at normal incidence. This simplified formula for R(θ) accounts for all of the relations between R(θ) and elastic properties first described by Koefoed in 1955.

The Lateral Shift of Reflection Sh-Wave on an Interface of Two Media

2014 ◽  
Vol 488-489 ◽  
pp. 923-925 ◽  
Author(s):  
An Ling Wang ◽  
Fu Ping Liu
Keyword(s):  
Phase Shift ◽  
Reflection Coefficient ◽  
Seismic Wave ◽  
Critical Angle ◽  
Lateral Shift ◽  
Angle Of Incidence ◽  
Sh Wave ◽  
Order Of Magnitude

Using the phase shift of reflection coefficient of SH seismic wave at the interface of strata, we derived the lateral shift of total reflected SH-wave, drawn the curves of lateral shift. The results show that for glancing wave or angle of incidence being near the critical angle, the lateral shift are very large.angle of incidence the lateral shift is the same order of magnitude as the wavelength (period).

The Lateral Shift of SV-Wave on the Free Surface of Stratum

2013 ◽  
Vol 838-841 ◽  
pp. 1534-1537
Author(s):  
An Ling Wang ◽  
Fu Ping Liu
Keyword(s):  
Free Surface ◽  
Phase Shift ◽  
Reflection Coefficient ◽  
Seismic Wave ◽  
Critical Angle ◽  
Large Error ◽  
Lateral Shift ◽  
Angle Of Incidence ◽  
Reflected Wave ◽  
Order Of Magnitude

Using the phase shift of reflection coefficient of SV seismic wave at the free surface of stratum, we derived the lateral shift of total reflected SV seismic wave, given formulae of it, and drawn the curves of lateral shift, The results show that reflected wave of VS-wave exists negative shift; for glancing wave or angle of incidence being near the critical angle, a large error can be caused, In other angle of incidence the lateral shift is the same order of magnitude as the wavelength.

The Shift Time of SV-Wave on the Free Surface of Stratum

2014 ◽  
Vol 488-489 ◽  
pp. 530-533
Author(s):  
An Ling Wang ◽  
Fu Ping Liu
Keyword(s):  
Free Surface ◽  
Phase Shift ◽  
Reflection Coefficient ◽  
Seismic Wave ◽  
Critical Angle ◽  
Angle Of Incidence ◽  
Large Shift ◽  
Reflected Wave ◽  
Negative Shift ◽  
Order Of Magnitude

Using the phase shift of reflection coefficient of SV seismic wave at the free surface of stratum, we derived the the shift time of total reflected SV seismic wave, given formulae of shift timeand drawn the curves of shift time. The results show that reflected wave of VS-wave exists negative shift;for glancing wave or angle of incidence being near the critical angle, a large shift can be caused , In other angle of incidence the shift is the same order of magnitude as the wavelength.

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