AVA USING SPHERICAL WAVE REFLECTION COEFFICIENT: APPLICATION TO CANA FIELD

As an approximation of the spherical-wave reflection coefficient (SRC), the plane-wave reflection coefficient does not fully describe the reflection phenomenon of a seismic wave generated by a point source. The applications of SRC to improve analyses of seismic data have also been studied. However, most of the studies focus on the time-domain SRC and its benefit to using the long-offset information instead of the dependency of SRC on frequency. Consequently, we have investigated and accounted for the frequency-dependent spherical-wave reflection coefficient (FSRC) and analyzed the feasibility of this type of inversion. Our inversion strategy requires a single incident angle using reflection data for inverting the density and velocity ratios, which is distinctly different from conventional inversion methods using amplitude variation with offset. Hence, this investigation provides an alternative approach for estimating media properties in some contexts, especially when the range of aperture of the reflection angles is limited. We apply the FSRC theory to the inversion of noisy synthetic and field data using a heuristic algorithm. The multirealization results of the inversion strategy are consistent with the feasibility analysis and demonstrate the potential of the outlined method for practical application.

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Frequency-dependent spherical-wave nonlinear AVO inversion in elastic media

Geophysical Journal International ◽

10.1093/gji/ggaa312 ◽

2020 ◽

Vol 223 (2) ◽

pp. 765-776

Author(s):

Guangsen Cheng ◽

Xingyao Yin ◽

Zhaoyun Zong

Keyword(s):

Reflection Coefficient ◽

Wave Reflection ◽

Fresnel Zone ◽

Spherical Wave ◽

Inversion Method ◽

Elastic Media ◽

Amplitude Variation With Offset ◽

Avo Inversion ◽

Well Location ◽

The Stability

SUMMARY The plane-wave reflection coefficient (PRC) plays a remarkable role in conventional amplitude variation with offset (AVO) analysis and inversion. Compared with the widely exploited PRC that breaks down at the near- and supercritical incidence angles, the spherical-wave reflection coefficient (SRC) can overcome the influence of wide-angle reflection and give an accurate description of the actual seismic wave reflection phenomenon based on spherical-wave fronts. However, SRC is not widely used in AVO inversion due to its nonlinearity and computational complexity. In our study, the characteristics of frequency–depth-dependent monochromatic SRC are discussed and a novel three-parameter SRC is derived. Compared with the conventional six-parameter SRC, the novel three-parameter SRC improves the stability of spherical-wave AVO inversion. In addition, the concept of SRC within the Fresnel zone is proposed, and the accuracy of SRC within the Fresnel zone in the deep subsurface is tested. Finally, a nonlinear spherical-wave AVO inversion method for elastic media is proposed, which can make full use of all frequency components of wavelet. The robustness of the proposed method is verified by the application on synthetic seismogram with white Gaussian noise. The feasibility and practicability of this method are verified by comparing the spherical-wave AVO inversion results with the filtered well logs at the known well location.

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Approximation of spherical wave reflection coefficient from rough sea surface

20th Iranian Conference on Electrical Engineering (ICEE2012) ◽

10.1109/iraniancee.2012.6292552 ◽

2012 ◽

Cited By ~ 1

Author(s):

Mohammad Reza Mousavi ◽

Mahmood Karimi ◽

Azizollah Jamshidi

Keyword(s):

Reflection Coefficient ◽

Wave Reflection ◽

Spherical Wave ◽

Sea Surface ◽

Rough Sea Surface ◽

Rough Sea

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Frequency-Dependent Inversion Using Spherical-Wave Reflection Coefficient with Critical and Post-Critical Offsets

10.3997/2214-4609.202010763 ◽

2020 ◽

Author(s):

B. Yan ◽

S. Wang ◽

R. Fang

Keyword(s):

Reflection Coefficient ◽

Wave Reflection ◽

Spherical Wave ◽

Frequency Dependent

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A novel expression of the spherical-wave reflection coefficient at a plane interface

Geophysical Journal International ◽

10.1093/gji/ggx308 ◽

2017 ◽

Vol 211 (2) ◽

pp. 700-717 ◽

Cited By ~ 5

Author(s):

Jingnan Li ◽

Shangxu Wang ◽

Yonghui Tao ◽

Chunhui Dong ◽

Genyang Tang

Keyword(s):

Reflection Coefficient ◽

Complex Plane ◽

Wave Reflection ◽

Incidence Angle ◽

Velocity Ratio ◽

Spherical Wave ◽

Density Ratio ◽

Plane Interface ◽

Analytical Equation ◽

Wave Number

Abstract The spherical-wave reflection coefficient (SRC) describes the reflection strength when seismic waves emanating from a point source impinge on an interface. In this study, the SRC at a plane interface between two infinite half-spaces is investigated. We derive an analytical equation of the SRC when kR → 0 (k is the wave number and R is the wave propagation distance). It only depends on the density ratio; it is independent of the velocity ratio and incidence angle. On the other hand, we find that the SRCs at different kR lie along an elliptical curve on the complex plane (the complex plane is a geometric representation of the complex numbers established by the real axis and perpendicular imaginary axis). Based on this feature, we construct a new analytical equation for the reflected spherical wave with high accuracy, which is applicable to both small and large kR. Using the elliptical distribution of the SRCs for a series of frequencies recorded at only one spatial location, the density and velocity ratios can be extracted. This study complements the spherical-wave reflection theory and provides a new basis for acoustic parameters inversion, particularly density inversion.

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Seismic inversion using complex spherical-wave reflection coefficient at different offsets and frequencies

Geophysics ◽

10.1190/geo2020-0787.1 ◽

2021 ◽

pp. 1-47

Author(s):

Guangsen Cheng ◽

Xingyao Yin ◽

Zhaoyun Zong ◽

Tongxing Xia ◽

Jianli Wang ◽

...

Keyword(s):

Reflection Coefficient ◽

Wave Amplitude ◽

Wave Reflection ◽

Spherical Wave ◽

Frequency Component ◽

Seismic Inversion ◽

Synthetic Seismogram ◽

S Wave ◽

Wave Inversion ◽

Frequency Components

Compared with the plane-wave reflection coefficient, the spherical-wave reflection coefficient (SRC) can more accurately describe the reflected wavefield excited by a point source, especially in the case of low seismic frequency and short travel distance. However, unlike the widely used plane-wave amplitude-variation-with-offset/frequency (AVO/AVF) inversion, the practical application of spherical-wave AVO/AVF inversion in multilayer elastic media is still in the exploratory stage. One of the difficulties is how to fully use the amplitude and phase information of the complex-valued SRC and the spherical-wave response property of each frequency component to obtain the spherical-wave synthetic seismogram in multilayer elastic media. In view of this, we have developed a complex convolution model considering the amplitude and phase information of a SRC to obtain the complex synthetic seismogram of a certain frequency component. A simple harmonic superposition method is further developed. By superposing the complex synthetic seismograms of different frequency components, the synthetic seismogram of the full-frequency band can be obtained. In addition, a novel three-parameter SRC in terms of P- and S-wave moduli and density is derived. Based on the SRC and complex seismic traces with different offsets (or incidence angles) and frequency components, an inversion approach of complex spherical-wave amplitude and phase variation with offset and frequency is proposed. A noisy synthetic data example verifies the robustness of our complex spherical-wave inversion approach. Field data examples indicate that the P- and S-wave moduli estimated by the complex spherical-wave inversion approach can reasonably match the filtered well-logging data. Considering spherical waves rather than plane waves can improve the accuracy of seismic inversion results.

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