Synthetic vertical seismic profile

Geophysics ◽  
1981 ◽  
Vol 46 (6) ◽  
pp. 880-891 ◽  
Author(s):  
K. Dautenhahn Wyatt
Keyword(s):  
Seismic Profile ◽  
Synthetic Seismogram ◽  
Domain Model ◽  
Vertical Seismic Profile ◽  
Seismic Section ◽  
The Earth ◽  
Sonic Log ◽  
Wave Propagation Problem ◽  
Layering Effect ◽  
Insight Into

A time‐domain model has been developed for calculation of a synthetic vertical seismic profile (SVSP) from a sonic log recorded in a borehole. The SVSP has proven to be extremely useful in the interpretation of seismic data since it allows the interpreter to analyze the propagation of the source pulse through the earth in depth as well as time. Previously, the synthetic seismogram technique allowed analysis of the earth’s response to the source pulse at the surface only. However, the development of the SVSP allows insight into the entire wave propagation problem since the calculation shows the response of the earth to the source pulse at any depth point in the subsurface. For example, the synthetic seismogram can be used to identify an event on the seismic section as a multiple, whereas, the SVSP cannot only identify a multiple, but can also show which path the source pulse took through the earth layers to create the multiple. The SVSP can also be used to analyze the change in character of the source pulse due to the layering effect of the earth, for example, effects of a thin bed sequence; to study amplitude variations due to transmission losses; and to examine the effects of different source pulse bandwidths on the final surface seismogram, etc. As interpreters gain experience in analyzing the SVSP, many more applications are expected to appear.

Tutorial: Tying a well to seismic using a blocked sonic log

2014 ◽  
Vol 2 (2) ◽  
pp. SD1-SD7 ◽  
Author(s):  
Donald A. Herron
Keyword(s):  
Seismic Data ◽  
Seismic Profile ◽  
Synthetic Seismogram ◽  
Well Bore ◽  
Vertical Seismic Profile ◽  
Sonic Log ◽  
Pencil And Paper

Well ties to seismic data establish the fundamental link between geology as we measure it in a well bore and the seismic expression of geology that we work with as interpreters. This tutorial presents an example of tying a well to time-processed seismic data using a blocked sonic log for a case in which neither a vertical seismic profile, a synthetic seismogram, nor a check-shot survey is available. The described procedure requires only pencil and paper to quickly produce an acceptable well tie.

VSP CASE HISTORY, KANPA 1A, THE WESTERN OFFICER BASIN

1985 ◽  
Vol 25 (1) ◽  
pp. 254
Author(s):  
T.J.C. Prudence ◽  
J. Flentri
Keyword(s):  
Seismic Profile ◽  
Field Configuration ◽  
Synthetic Seismogram ◽  
Target Interval ◽  
Seismic Section ◽  
Temporal Sampling ◽  
Consistent Field ◽  
Vsp Data ◽  
Tube Wave ◽  
Zero Phase

The Kanpa 1A Vertical Seismic Profile (VSP) was conducted for Shell by Schlumberger and incorporated variable time and depth sampling, different source offsets and recording in cased and uncased hole. Processing was performed using Shell proprietary programs, with particular attention to:Editing and resampling of the data setSeparation of upgoing and downgoing waves using FK and median filtersComparison of gain recovery based on modelling the amplitude decay of direct arrivals with an averaging process (AGC)Sensitivity of the final VSP stack to blanking of residual tube wave noiseZero-phase whitening of the VSP traceStacked VSP traces for Kanpa 1A were compared with a zero-phase seismic section and synthetic seismogram at the well. The VSP/seismic match is good and, due to poor synthetic/seismic correlation, was the basis for the final seismic/well tie. Interpretation of deep VSP data enabled the estimation of formation boundaries below the total depth of the well.It is concluded that VSPs can be invaluable in establishing well ties where seismic is poor or when detailed correlation is required (e.g. stratigraphic traps). Reflectors "ahead of the bit" can be interpreted from VSPs based on assumed velocities and VSP/seismic tie, and the predicted thickness and seismic character of the target interval. A consistent field configuration is recommended for acquisition with attention to tube wave suppression and adequate spatial and temporal sampling. Previous processing experience is advantageous if quick and reliable VSP results are required for decisions while drilling.

Smooth inversion of VSP traveltime data

Geophysics ◽  
1999 ◽  
Vol 64 (3) ◽  
pp. 659-661 ◽  
Author(s):  
Daniel Lizarralde ◽  
Steve Swift
Keyword(s):  
Least Squares ◽  
Waveform Inversion ◽  
Seismic Profile ◽  
Vertical Seismic Profile ◽  
Depth Profiles ◽  
Depth Function ◽  
The Earth ◽  
Damping Parameter ◽  
Damped Least Squares

Vertical seismic profile (VSP) direct arrivals provide an insitu measurement of traveltime with depth into the earth. In this note, we describe a weighted, damped least‐squares inversion of VSP traveltimes for a smooth velocity/depth function that inherently reveals the resolution of the data. Smooth velocity/depth profiles of this type are suitable for migration or as a starting models for waveform inversion or tomography. The application of this inversion is particularly simple, requiring only the value of the damping parameter to be determined, and this value is determined from residual statistics.

scholarly journals Imaging vertical structures using Marchenko methods with vertical seismic-profile data

Geophysics ◽  
2020 ◽  
Vol 85 (2) ◽  
pp. S103-S113 ◽  
Author(s):  
Angus Lomas ◽  
Satyan Singh ◽  
Andrew Curtis
Keyword(s):  
Synthetic Data ◽  
Arbitrary Point ◽  
Seismic Profile ◽  
Single Scattering ◽  
Variable Density ◽  
Vertical Seismic Profile ◽  
The Earth ◽  
Imaging Result ◽  
Fault Structures ◽  
Internal Multiples

Marchenko methods use seismic data acquired at or near the surface of the earth to estimate seismic signals as if the receiver (now a virtual receiver) was at an arbitrary point inside the subsurface of the earth. This process is called redatuming, and it is central to subsurface imaging. Marchenko methods estimate the multiply scattered components of these redatumed signals, which is not the case for most other redatuming techniques that are based on single-scattering assumptions. As a result, images created using Marchenko redatumed signals contain a reduction in the artifacts that usually contaminate migrated seismic images due to improper handling of internal multiples. We exploit recent theoretical advances that enable virtual sources and virtual receivers to be placed at arbitrary points inside the subsurface as a means to incorporate vertical seismic profile (VSP) data into Marchenko methods. The advantage of including this type of data is that the additional acquisition boundary increases subsurface illumination, which in turn enables vertical interfaces and steeply dipping structures to be imaged. We develop this methodology using two synthetic data sets. The first is created using a simple variable density but constant velocity subsurface model. In this example, we find that our newly devised VSP Marchenko imaging methodology enables imaging of horizontal and vertical structures and that optimal results are achieved by combining these images with those created using standard Marchenko imaging. A second example demonstrates that the method can be applied to more realistic subsurface structures, in this case a modified version of the Marmousi 2 model. We determine the applicability of the methods to image fault structures with the final imaging result containing reduced contamination due to internal multiples and an improvement in the imaging of fault structures when compared to other standard imaging methods alone.

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.

Trace Pair Filtering for Separation of Upgoing and Downgoing Waves in Vsp (Vertical Seismic Profile)

1990 ◽  
Vol 45 (2) ◽  
pp. 181-203
Author(s):  
F. Glangeaud ◽  
P. Durand ◽  
J. L. Mari ◽  
F. Coppens
Keyword(s):  
Seismic Profile ◽  
Vertical Seismic Profile
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