On: “Pulse distortion in depth migration,” M. Tygel, J. Schleicher, and P. Hubral (October 1994 GEOPHYSICS, 59, p. 1561–1569).

Geophysics ◽  
1995 ◽  
Vol 60 (6) ◽  
pp. 1942-1944 ◽  
Author(s):  
Arthur E. Barnes
Keyword(s):  
Seismic Reflection ◽  
Prestack Depth Migration ◽  
Seismic Reflection Data ◽  
Depth Migration ◽  
Reflection Data ◽  
Time Migration ◽  
Pulse Distortion ◽  
Nmo Stretch ◽  
Frequency Shifting

Tygel et al. have written an excellent and rigorous discussion of pulse distortion in seismic reflection data caused by prestack depth migration. Such distortion is easily understood by recognizing that it is more or less the same effect as normal moveout (NMO) stretch combined with frequency shifting due to poststack time migration.

scholarly journals Imaging complex structure in shallow seismic-reflection data using prestack depth migration

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. B175-B181 ◽  
Author(s):  
John H. Bradford ◽  
Lee M. Liberty ◽  
Mitch W. Lyle ◽  
William P. Clement ◽  
Scott Hess
Keyword(s):  
Seismic Reflection ◽  
Complex Structure ◽  
Volcanic Rocks ◽  
Depth Range ◽  
Prestack Depth Migration ◽  
Measured Velocity ◽  
Seismic Reflection Data ◽  
Depth Migration ◽  
Time Migration ◽  
Shallow Seismic

Prestack depth migration (PSDM) analysis has the potential to significantly improve the accuracy of both shallow seismic reflection images and the measured velocity distributions. In a study designed to image faults in the Alvord Basin, Oregon, at depths from [Formula: see text], PSDM produced a detailed reflection image over the full target depth range. In contrast, poststack time migration produced significant migration artifacts in the upper [Formula: see text] that obscured reflection events and limited the structural interpretation in the shallow section. Additionally, an abrupt increase from [Formula: see text] to [Formula: see text] in the PSDM velocity model constrained the interpretation of the transition from sedimentary basin fill to basement volcanic rocks. PSDM analysis revealed a complex extensional history with at least two distinct phases of basin growth and a midbasin basement high that forms the division between two major basin compartments.

3-D preserved amplitude prestack depth migration on a workstation

Geophysics ◽  
1999 ◽  
Vol 64 (1) ◽  
pp. 222-229 ◽  
Author(s):  
Philippe Thierry ◽  
Gilles Lambaré ◽  
Pascal Podvin ◽  
Mark S. Noble
Keyword(s):  
Seismic Reflection ◽  
Velocity Fields ◽  
Prestack Depth Migration ◽  
Data Set ◽  
Seismic Reflection Data ◽  
Depth Migration ◽  
Cpu Time ◽  
Reflection Data ◽  
Marine Data ◽  
Single Processor

We present an algorithm based on the ray+Born approximation for 3-D preserved amplitude prestack depth migration (PAPsDM) of seismic reflection data. This ray+Born inversion scheme allows the quantitative recovery of model perturbations. The Green’s functions are estimated by dynamic ray tracing in 3-D heterogeneous smooth velocity fields with a wavefront construction (WFC) method. The PAPsDM algorithm was implemented on a single‐processor Sun Sparc 20 workstation. Special attention was paid to CPU efficiency and memory requirements. We present an application on a 3-D real marine data set (13 Gbytes). About one week of CPU time is needed to obtain a migrated image of 7 × 1 × 1 km.

Depth migration and interpretation of the COCORP Wind River, Wyoming, seismic reflection data

Geology ◽  
1983 ◽  
Vol 11 (8) ◽  
pp. 462 ◽  
Author(s):  
Heloise Bloxsom Lynn ◽  
Spencer Quam ◽  
George A. Thompson
Keyword(s):  
Seismic Reflection ◽  
Seismic Reflection Data ◽  
Depth Migration ◽  
Reflection Data

Another look at NMO stretch

Geophysics ◽  
1992 ◽  
Vol 57 (5) ◽  
pp. 749-751 ◽  
Author(s):  
Arthur E. Barnes
Keyword(s):  
Seismic Reflection ◽  
Qualitative Assessment ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Amplitude Spectra ◽  
Nmo Correction ◽  
Zero Offset ◽  
Nmo Stretch ◽  
Dominant Frequencies

The normal moveout (NMO) correction is applied to seismic reflection data to transform traces recorded at non‐zero offset into traces that appear to have been recorded at zero offset; this introduces undesirable distortions called NMO stretch (Buchholtz, 1972). NMO stretch must be understood because it lengthens waveforms and thereby reduces resolution. Buchholtz (1972) gives a qualitative assessment of NMO stretch, Dunkin and Levin (1973) derive its effect on the amplitude spectra of narrow waveforms, while Yilmaz (1987, p. 160) considers its effect on dominant frequencies. These works are approximate and do not show how spectral distortions vary through time.

Application of 3D seismic techniques to evaluate ore resources in the West Wits Line goldfield and portions of the West Rand goldfield, South Africa

Geophysics ◽  
2012 ◽  
Vol 77 (5) ◽  
pp. WC163-WC171 ◽  
Author(s):  
Musa S. D. Manzi ◽  
Mark A. S. Gibson ◽  
Kim A. A. Hein ◽  
Nick King ◽  
Raymond J. Durrheim
Keyword(s):  
Seismic Reflection ◽  
Signal To Noise Ratio ◽  
Mine Planning ◽  
3D Seismic ◽  
Borehole Data ◽  
The West ◽  
Seismic Reflection Data ◽  
Witwatersrand Basin ◽  
Reflection Data ◽  
Time Migration

As expensive as 3D seismic reflection surveys are, their high cost is justified by improved imaging of certain ore horizons in some of the Witwatersrand basin gold mines. The merged historical 3D seismic reflection data acquired for Kloof and South Deep mines forms an integral part of their Ventersdorp Contact Reef mine planning and development programme. The recent advances in 3D seismic technology have motivated the reprocessing and reinterpretation of the old data sets using the latest algorithms, therefore significantly increasing the signal-to-noise ratio of the data. In particular, the prestack time migration technique has provided better stratigraphic and structural imaging in complex faulted areas, such as the Witwatersrand basin, relative to older poststack migration methods. Interpretation tools such as seismic attributes have been used to identify a number of subtle geologic structures that have direct impact on ore resource evaluation. Other improvements include more accurate mapping of the depths, dip, and strike of the key seismic horizons and auriferous reefs, yielding a better understanding of the interrelationship between fault activity and reef distribution, and the relative chronology of tectonic events. The 3D seismic data, when integrated with underground mapping and borehole data, provide better imaging and modeling of critical major fault systems and zones of reef loss. Many faults resolve as multifault segments that bound unmined blocks leading to the discovery and delineation of resources in faulted areas of the mines.

Response by Arthur E. Barnes to the reply by the authors

Geophysics ◽  
1995 ◽  
Vol 60 (6) ◽  
pp. 1947-1947 ◽  
Author(s):  
Arthur E. Barnes
Keyword(s):  
Lateral Velocity ◽  
Prestack Depth Migration ◽  
Depth Migration ◽  
Time Migration ◽  
Pulse Distortion ◽  
Velocity Variations ◽  
Zero Offset ◽  
Complex Geology

I appreciate the thoughtful and thorough response given by Tygel et al. They point out that even for a single dipping reflector imaged by a single non‐zero offset raypath, pulse distortion caused by “standard processing” (NM0 correction‐CMP sort‐stack‐time migration) and pulse distortion caused by prestack depth migration are not really the same, because the reflecting point is mispositioned in standard processing. Within a CMP gather, this mispositioning increases with offset, giving rise to “CMP smear.” CMP smear degrades the stack, introducing additional pulse distortion. Where i‐t is significant, and where lateral velocity variations or reflection curvature are large, such as for complex geology, the pulse distortion of standard processing can differ greatly from that of prestack depth migration.

Slowness-driven Gaussian-beam prestack depth migration for low-fold seismic data

Geophysics ◽  
2009 ◽  
Vol 74 (6) ◽  
pp. WCA35-WCA45 ◽  
Author(s):  
Chaoshun Hu ◽  
Paul L. Stoffa
Keyword(s):  
Gaussian Beam ◽  
Seismic Data ◽  
Fresnel Zone ◽  
Seismic Energy ◽  
Real Data ◽  
Ocean Bottom ◽  
Prestack Depth Migration ◽  
Seismic Reflection Data ◽  
Depth Migration ◽  
Reflection Data

Subsurface images based on low-fold seismic reflection data or data with geometry acquisition limitations, such as obtained from ocean-bottom seismography (OBS), are often corrupted by migration swing artifacts. Incorporating prestack instantaneous slowness information into the imaging condition can significantly reduce these migration swing artifacts and improve image quality, especially for areas with poor illumination. We combine the horizontal surface slowness information of observed seismic data with Gaussian-beam depth migration to implement a new slowness-driven Gaussian-beam prestack depth migration whereby Fresnel weighting is combined naturally with beam summation. The prestack instantaneous slowness information is extracted from the original OBS or shot gathers using local slant stacks and is combined with a local semblance analysis. During migration, we propagate the seismic energy downward, knowing its instantaneous slowness information. At each image location, the beam summation is localized in a resolution-dependent Fresnel zone; the instantaneous slowness information controls the beam summation. Synthetic and real data examples confirm that slowness-driven Gaussian-beam migration can suppress most noise from inadequate stacking and give a clearer migration result.

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