Traveltime inversion of both direct and reflected arrivals in vertical seismic profile data

Geophysics ◽  
1989 ◽  
Vol 54 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Edward L. Salo ◽  
Gerard T. Schuster
Keyword(s):  
Least Squares ◽  
Velocity Structure ◽  
Seismic Profile ◽  
Profile Data ◽  
Vertical Seismic Profile ◽  
Data Set ◽  
Traveltime Inversion ◽  
Sonic Log ◽  
Vsp Data

Traveltimes from both direct and reflected arrivals in a VSP data set (Bridenstein no. 1 well in Oklahoma) are inverted in a least‐squares sense for velocity structure. By comparing the structure from inversion to the sonic log, we conclude that the accuracy of the reconstructed velocities is greater than that found when only the direct arrivals are used. Extensive tests on synthetic VSP data confirm this observation. Apparently, the additional reflection traveltime equations aid in averaging out the traveltime errors, as well as reducing the slowness variance in reflecting layers. These results are consistent with theory, which predicts a decrease in a layer’s slowness variance with an increase in the number and length of terminating reflected rays. For the Bridenstein data set, 130 direct traveltimes and 399 primary reflection traveltimes were used in the inversion.

Integrated prestack depth migration of vertical seismic profile and surface seismic data from the Rocky Mountain Foothills of southern Alberta, Canada

Geophysics ◽  
2003 ◽  
Vol 68 (6) ◽  
pp. 1782-1791 ◽  
Author(s):  
M. Graziella Kirtland Grech ◽  
Don C. Lawton ◽  
Scott Cheadle
Keyword(s):  
Seismic Data ◽  
Rocky Mountain ◽  
Velocity Model ◽  
Seismic Profile ◽  
Vertical Seismic Profile ◽  
Prestack Depth Migration ◽  
Data Set ◽  
Depth Migration ◽  
Southern Alberta ◽  
Vsp Data

We have developed an anisotropic prestack depth migration code that can migrate either vertical seismic profile (VSP) or surface seismic data. We use this migration code in a new method for integrated VSP and surface seismic depth imaging. Instead of splicing the VSP image into the section derived from surface seismic data, we use the same migration algorithm and a single velocity model to migrate both data sets to a common output grid. We then scale and sum the two images to yield one integrated depth‐migrated section. After testing this method on synthetic surface seismic and VSP data, we applied it to field data from a 2D surface seismic line and a multioffset VSP from the Rocky Mountain Foothills of southern Alberta, Canada. Our results show that the resulting integrated image exhibits significant improvement over that obtained from (a) the migration of either data set alone or (b) the conventional splicing approach. The integrated image uses the broader frequency bandwidth of the VSP data to provide higher vertical resolution than the migration of the surface seismic data. The integrated image also shows enhanced structural detail, since no part of the surface seismic section is eliminated, and good event continuity through the use of a single migration–velocity model, obtained by an integrated interpretation of borehole and surface seismic data. This enhanced migrated image enabled us to perform a more robust interpretation with good well ties.

Specular interferometric imaging of vertical seismic profile data

2015 ◽  
Vol 3 (3) ◽  
pp. SW57-SW62 ◽  
Author(s):  
Yunsong Huang ◽  
Ruiqing He ◽  
Chaiwoot Boonyasiriwat ◽  
Yi Luo ◽  
Gerard Schuster
Keyword(s):  
Ray Tracing ◽  
Field Data ◽  
Seismic Profile ◽  
The Other ◽  
Interferometric Imaging ◽  
Profile Data ◽  
Vertical Seismic Profile ◽  
Ghost Image ◽  
Primary Image ◽  
Vsp Data

We introduce the concept of seminatural migration of multiples in vertical seismic profile (VSP) data, denoted as specular interferometric migration, in which part of the kernel is computed by ray tracing and the other part is obtained from the data. It has the advantage over standard migration of ghost reflections, in that the well statics are eliminated and the migration image is no more sensitive to velocity errors than migration of VSP primaries. Moreover, the VSP ghost image has significantly more subsurface illumination than the VSP primary image. The synthetic and field data results validate the effectiveness of this method.

Anisotropic frequency-dependent spreading of seismic waves from first-arrival vertical seismic profile data analysis

Geophysics ◽  
2013 ◽  
Vol 78 (6) ◽  
pp. C41-C52 ◽  
Author(s):  
Amin Baharvand Ahmadi ◽  
Igor Morozov
Keyword(s):  
Seismic Waves ◽  
Seismic Profile ◽  
Anisotropic Scattering ◽  
Profile Data ◽  
Vertical Seismic Profile ◽  
Data Set ◽  
Frequency Dependent ◽  
Geometric Spreading ◽  
First Arrival ◽  
Viscoelastic Modeling

A model of first-arrival amplitude decay combining geometric spreading, scattering, and inelastic dissipation is derived from a multioffset, 3D vertical seismic profile data set. Unlike the traditional approaches, the model is formulated in terms of path integrals over the rays and without relying on the quality factor ([Formula: see text]) for rocks. The inversion reveals variations of geometric attenuation (wavefront curvatures and scattering, [Formula: see text]) and the effective attenuation parameter ([Formula: see text]) with depth. Both of these properties are also found to be anisotropic. Scattering and geometric spreading (focusing and defocusing) significantly affect seismic amplitudes at lower frequencies and shallower depths. Statistical analysis of model uncertainties quantitatively measures the significance of these results. The model correctly predicts the observed frequency-dependent first-arrival amplitudes at all frequencies. This and similar models can be applied to other types of waves and should be useful for true-amplitude studies, including inversion, inverse [Formula: see text]-filtering, and amplitude variations with offset analysis. With further development of petrophysical models of internal friction and elastic scattering, attenuation parameters [Formula: see text] and [Formula: see text] should lead to constraints on local heterogeneity and intrinsic physical properties of the rock. These parameters can also be used to build models of the traditional frequency-dependent [Formula: see text] for forward and inverse numerical viscoelastic modeling.

SV-P extraction and imaging for far-offset vertical seismic profile data

2015 ◽  
Vol 3 (3) ◽  
pp. SW27-SW35 ◽  
Author(s):  
Yandong Li ◽  
Bob A. Hardage
Keyword(s):  
Ray Tracing ◽  
Marcellus Shale ◽  
Seismic Profile ◽  
P Wave ◽  
Time Varying ◽  
Profile Data ◽  
Vertical Seismic Profile ◽  
Optimal Receiver ◽  
Common Depth Point ◽  
Vsp Data

We have analyzed vertical seismic profile (VSP) data acquired across a Marcellus Shale prospect and found that SV-P reflections could be extracted from far-offset VSP data generated by a vertical-vibrator source using time-variant receiver rotations. Optimal receiver rotation angles were determined by a dynamic steering of geophones to the time-varying approach directions of upgoing SV-P reflections. These SV-P reflections were then imaged using a VSP common-depth-point transformation based on ray tracing. Comparisons of our SV-P image with P-P and P-SV images derived from the same offset VSP data found that for deep targets, SV-P data created an image that extended farther from the receiver well than P-P and P-SV images and that spanned a wider offset range than P-P and P-SV images do. A comparison of our VSP SV-P image with a surface-based P-SV profile that traversed the VSP well demonstrated that SV-P data were equivalent to P-SV data for characterizing geology and that a VSP-derived SV-P image could be used to calibrate surface-recorded SV-P data that were generated by P-wave sources.

Frequency-dependent reflection wave-equation traveltime inversion from walkaway vertical seismic profile data

Geophysics ◽  
2019 ◽  
Vol 84 (6) ◽  
pp. R947-R961
Author(s):  
Yikang Zheng ◽  
Yibo Wang ◽  
Qiang Luo ◽  
Xu Chang ◽  
Rongshu Zeng ◽  
...  
Keyword(s):  
Wave Equation ◽  
Calculated Data ◽  
Velocity Model ◽  
Seismic Profile ◽  
Initial Model ◽  
Vertical Seismic Profile ◽  
Frequency Dependent ◽  
Traveltime Inversion ◽  
Time Migration ◽  
Vsp Data

To accurately image the geologic structures from walkaway vertical seismic profile (VSP) data, it is necessary to estimate the subsurface velocity field with high resolution and enhanced illumination of deep reservoirs. Because full-waveform inversion (FWI) suffers from cycle skipping when the initial model is far from the true model, we have adopted frequency-dependent reflection wave-equation traveltime inversion (FRWT) to generate the background velocity model for VSP migration. The upgoing reflection data are separated from the original shot gathers, and dynamic warping is used to evaluate the traveltime differences between the observed data and the calculated data. Different frequency bands of the data are inverted in sequence to reconstruct the velocity model with higher resolution. We also implement wavefield decomposition on the gradient field to extract the contributions of reflection components and improve the updated model. The inverted results obtained from FRWT can be used as the initial model for conventional FWI or the velocity model for reverse time migration. The experiments on synthetic data and field data demonstrate that our approach can effectively recover the background velocity model from walkaway VSP data.

Local migration with extrapolated VSP Green’s functions

Geophysics ◽  
2009 ◽  
Vol 74 (1) ◽  
pp. SI15-SI26 ◽  
Author(s):  
Xiang Xiao ◽  
Gerard T. Schuster
Keyword(s):  
Velocity Model ◽  
Seismic Profile ◽  
Imaging Method ◽  
Local Velocity ◽  
Dynamic Effects ◽  
Vertical Seismic Profile ◽  
Data Set ◽  
Numerical Tests ◽  
Vsp Data ◽  
Backward Propagation

We have developed a novel vertical seismic profile (VSP) imaging method that requires only a local velocity model around the well. This method is denoted as a “local migration,” where the model-based forward-propagation and backward-propagation operators are computed using a local velocity model between the well and the target body. The velocity model for the complex overburden and salt body is not needed, and the source-side statics are automatically accounted for. In addition, kinematic and dynamic effects, including anisotropy, absorption, and other unknown/undefined rock effects outside of this local velocity model, are mostly accounted for. Numerical tests on an acoustic 2D Sigsbee VSP data set, an elastic salt model, and offset 2D VSP data in the Gulf of Mexico partly validate the effectiveness of this method by accurately imaging the sediments next to the vertical well.

scholarly journals Elastic full-waveform inversion of vertical seismic profile data acquired with distributed acoustic sensors

Geophysics ◽  
2018 ◽  
Vol 83 (3) ◽  
pp. R273-R281 ◽  
Author(s):  
Anton Egorov ◽  
Julia Correa ◽  
Andrej Bóna ◽  
Roman Pevzner ◽  
Konstantin Tertyshnikov ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Particle Velocity ◽  
Waveform Inversion ◽  
Vertical Component ◽  
Seismic Profile ◽  
Full Waveform Inversion ◽  
Vertical Seismic Profile ◽  
Data Set ◽  
Full Waveform ◽  
Vsp Data

Distributed acoustic sensing (DAS) is a rapidly developing technology particularly useful for the acquisition of vertical seismic profile (VSP) surveys. DAS data are increasingly used for seismic imaging, but not for estimating rock properties. We have developed a workflow for estimating elastic properties of the subsurface using full-waveform inversion (FWI) of DAS VSP data. Whereas conventional borehole geophones usually measure three components of particle velocity, DAS measures a single quantity, which is an approximation of the strain or strain rate along the fiber. Standard FWI algorithms are developed for particle velocity data, and hence their application to DAS data requires conversion of these data to particle velocity along the fiber. This conversion can be accomplished by a specially designed filter. Field measurements show that the conversion result is close to vertical particle velocity as measured by geophones. Elastic time-domain FWI of a synthetic multioffset VSP data set for a vertical well shows that the inversion of the vertical component alone is sufficient to recover elastic properties of the subsurface. Application of the proposed workflow to a multioffset DAS data set acquired at the CO2CRC Otway Project site in Victoria, Australia, reveals salient subhorizontal layering consistent with the known geology of the site. The inverted [Formula: see text] model at the well location matches the upscaled [Formula: see text] log with a correlation coefficient of 0.85.

On: “An integrated surface and borehole seismic case study: Fort St. John Graben area, Alberta, Canada,” by R. C. Hinds, R. Kuzminski, N. L. Anderson, and B. R. Richards (November 1993 GEOPHYSICS, 58, p. 1662–1675).

Geophysics ◽  
1994 ◽  
Vol 59 (7) ◽  
pp. 1171-1171
Author(s):  
Miodrag M. Roksandic
Keyword(s):  
Case History ◽  
Seismic Profile ◽  
Interesting Case ◽  
Well Log ◽  
Profile Data ◽  
Vertical Seismic Profile ◽  
Vsp Data ◽  
Integrated Interpretation ◽  
Borehole Seismic

Hinds et al.’s paper is an interesting case history describing the acquisition and interpretive processing of VSP data and presenting an integrated interpretation of well log, surface seismic, and vertical seismic profile data. However, a question of principle arises. What is an integrated interpretation?

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