A guide to current uses of vertical seismic profiles

Geophysics ◽  
1985 ◽  
Vol 50 (12) ◽  
pp. 2473-2479 ◽  
Author(s):  
Michael L. Oristaglio
Keyword(s):  
Seismic Exploration ◽  
Significant Advance ◽  
Small Scale ◽  
Seismic Profiles ◽  
Surface Source ◽  
Reflection And Transmission ◽  
Reflected Waves ◽  
Vertical Seismic Profiles ◽  
Transmission Properties ◽  
The Earth

Vertical seismic profiles (VSPs) are small‐scale seismic surveys in which geophones are lowered into a well to record waves traveling both down into the earth (direct waves from the surface source and downgoing multiples) and back toward the surface (primary reflections and upgoing multiples). VSPs thus contain information about the reflection and transmission properties of the earth with a coverage that depends upon the geometry of the VSP experiment and the structure near the well. This article describes the uses of VSPs in seismic exploration that have been published in the last three years and is designed to complement the more detailed surveys by Hardage (1983) and Balch and Lee (1984). When the earth is horizontally layered, the well is vertical, and the source is close to the wellhead, upgoing and downgoing waves recorded by the VSP travel vertically, and the VSP can be used to calibrate surface seismic sections by providing the time‐to‐depth curve and allowing a detailed analysis of reflection and transmission properties of the earth at a given location. These applications rely heavily on signal processing to separate the upgoing and downgoing waves and to study their relationships to data recorded at the surface. When the earth varies laterally or when the source is offset from the well, the VSP can be used to complement surface surveys by providing high‐resolution images of structure near the well. Current work has concentrated on forming images from the reflected waves by the methods of common‐depth‐point (CDP) stacking and migration. Tomographic methods for inverting the traveltimes and amplitudes of transmitted waves are also being developed and will become important when downhole arrays and powerful downhole sources are available. The most significant advance in the next few years, however, will be the development of a reliable three‐axis tool with internal devices for determining both the orientation of the tool and the quality of its coupling to the borehole wall.

The use of vertical seismic profiles in seismic investigations of the earth

Geophysics ◽  
1982 ◽  
Vol 47 (6) ◽  
pp. 906-918 ◽  
Author(s):  
A. H. Balch ◽  
M. W. Lee ◽  
J. J. Miller ◽  
Robert T. Ryder
Keyword(s):  
Surface Profile ◽  
Acoustic Properties ◽  
Seismic Exploration ◽  
Seismic Profiles ◽  
Stratigraphic Sequence ◽  
Multiple Channel ◽  
Vertical Seismic Profiles ◽  
Surface Profiling ◽  
The Earth ◽  
Porous Zone

During the past 8 years, the U.S. Geological Survey has conducted an extensive investigation on the use of vertical seismic profiles (VSP) in a variety of seismic exploration applications. Seismic sources used were surface air guns, vibrators, explosives, marine air guns, and downhole air guns. Source offsets have ranged from 100 to 7800 ft. Well depths have been from 1200 to over 10,000 ft. We have found three specific ways in which VSPs can be applied to seismic exploration. First, seismic events observed at the surface of the ground can be traced, level by level, to their point of origin within the earth. Thus, one can tie a surface profile to a well log with an extraordinarily high degree of confidence. Second, one can establish the detectability of a target horizon, such as a porous zone. One can determine (either before or after surface profiling) whether or not a given horizon or layered sequence returns a detectable reflection to the surface. The amplitude and character of the reflection can also be observed. Third, acoustic properties of a stratigraphic sequence can be measured and sometimes correlated to important exploration parameters. For example, sometimes a relationship between apparent attenuation and sand percentage can be established. The technique shows additional promise of aiding surface exploration indirectly through studies of the evolution of the seismic pulse, studies of ghosts and multiples, and studies of seismic trace inversion techniques. Nearly all current seismic data‐processing techniques are adaptable to the processing of VSP data, such as normal moveout (NMO) corrections, stacking, single‐and multiple‐channel filtering, deconvolution, and wavelet shaping.

Tomographic determination of three‐dimensional seismic velocity structure using well logs, vertical seismic profiles, and surface seismic data

Geophysics ◽  
1987 ◽  
Vol 52 (8) ◽  
pp. 1085-1098 ◽  
Author(s):  
Stephen K. L. Chiu ◽  
Robert R. Stewart
Keyword(s):  
Velocity Structure ◽  
Seismic Velocity ◽  
Random Noise ◽  
Three Dimensional ◽  
Real Data ◽  
Well Logs ◽  
Seismic Profiles ◽  
Vertical Seismic Profiles ◽  
The Earth ◽  
Vsp Data

A tomographic technique (traveltime inversion) has been developed to obtain a two‐ or three‐dimensional velocity structure of the subsurface from well logs, vertical seismic profiles (VSP), and surface seismic measurements. The earth was modeled by continuous curved interfaces (polynomial or sinusoidal series), separating regions of constant velocity or transversely isotropic velocity. Ray tracing for each seismic source‐receiver pair was performed by solving a system of nonlinear equations which satisfy the generalized Snell’s law. Surface‐to‐borehole and surface‐to‐surface rays were included. A damped least‐squares formulation provided the updating of the earth model by minimizing the difference between the traveltimes picked from the real data and calculated traveltimes. Synthetic results indicated the following conclusions. For noise‐free cases, the inversion converged closely from the initial guess to the true model for either surface or VSP data. Adding random noise to the observations and performing the inversion indicated that (1) using surface data alone allows reconstruction of the broad velocity structure but with some inaccuracy; (2) using VSP data alone gives a very accurate but laterally limited velocity structure; and (3) the integration of both data sets produces a more laterally extensive, accurate image of the subsurface. Finally, a field example illustrates the viability of the method to construct a velocity structure from real data.

Computer processing of vertical seismic profile data

Geophysics ◽  
1983 ◽  
Vol 48 (3) ◽  
pp. 272-287 ◽  
Author(s):  
Myung W. Lee ◽  
Alfred H. Balch
Keyword(s):  
Seismic Profile ◽  
Computer Processing ◽  
Acoustic Properties ◽  
Well Logs ◽  
Seismic Exploration ◽  
Profile Data ◽  
Seismic Profiles ◽  
Vertical Seismic Profiles ◽  
Processing Techniques ◽  
Rock Parameters

Vertical seismic profiles (VSP) are a powerful tool in a variety of seismic exploration situations. Only after extensive computer processing of the raw field data, however, can the full value of this tool be realized. With the help of processing, relations between important rock parameters and acoustic properties can sometimes be established and highly reliable ties from well logs to surface seismic profiles can usually be obtained. The basic theory of the processing techniques is well known. However, the techniques used in processing standard surface seismic profiles usually must be modified to adapt them to the unique conditions associated with VSPs. Processing procedures, and their relevance to the interpretation of VSP and surface seismic profile data, are described.

To: “The use of verticle seismic profiles in seismic investigations of the earth,” June 1982, GEOPHYSICS.

Geophysics ◽  
1982 ◽  
Vol 47 (9) ◽  
pp. 1347-1347
Keyword(s):  
River Basin ◽  
Powder River Basin ◽  
Relative Amplitude ◽  
Seismic Profiles ◽  
Vertical Seismic Profiles ◽  
The Earth

In June 1982 Geophysics, the correct authors of “The use of vertical seismic profiles in seismic investigations of the earth” are A. H. Balch, M. W. Lee, J. J. Miller, and R. T. Ryder. R. T. Ryder was incorrectly listed as R. T. Taylor on the cover. The first two sentences of the caption for Figure 17 of the above paper (p. 917) should read “First Leo sand reflections and Minnekahta reflections from two wells in the eastern Powder River basin, Wyoming, from vertical seismic profiles (a) 50 ft thick Leo section, (b) Leo section 10 ft thick or less. Note the reduced relative amplitude of the Leo in (b).”

An introduction to seismic exploration of the Micang-Dabashan foothill belt in the Sichuan Basin

2018 ◽  
Vol 6 (4) ◽  
pp. SM39-SM50
Author(s):  
Jingbo Wang ◽  
Zhongshan Qi ◽  
Penggui Jing ◽  
Tianfa Zheng ◽  
Yanqi Li ◽  
...  
Keyword(s):  
Sichuan Basin ◽  
Oil And Gas ◽  
Seismic Exploration ◽  
Small Scale ◽  
Marine Strata ◽  
Piedmont Zone ◽  
Migration Imaging ◽  
Imaging Results ◽  
Platform Margin ◽  
The Sichuan Basin

Geologic studies indicate that the platform-margin reef-shallow facies in Permo-Triassic marine strata in the Micang-Dabashan foothill belt in the Sichuan Basin are favorable exploration targets for oil and gas exploration. However, the typical dual-complexity problem (complex surface condition and subsurface structure) brings a great challenge for seismic technology targeting of those potential oil and gas reservoirs. To overcome this problem, varieties of advanced seismic acquisition and processing methods have been used to improve the imaging quality of piedmont seismic data since 2000. Some improvements have been achieved: The reflection waves from the far offset and deep layer can be acquired in shot gathers from limestone outcropped areas, and the signal-to-noise ratio (S/N) of reflection and diffraction waves in the stack section has been enhanced significantly so as to reveal amounts of valuable geologic information. The resolution and the S/N of seismic migration imaging for the strong fold zone in marine strata have been improved partially, so that the structure of the step-fault zone and the enveloping of gypsum rock are clearer than those revealed by the old seismic section. Even so, actual drilling data demonstrate that the subsurface structures of the foothill belt are far more complex than those revealed by the current seismic imaging results. Therefore, postdrilling evaluation for the validity of seismic techniques implemented in the Nanjiang and Zhenba piedmont zone has been carried out. The results indicate that the current acquisition scheme and processing workflow cannot completely fulfill the requirements of high-precision velocity modeling and migration imaging of complex structures (such as footwalls of thrust fault and small-scale fault blocks) in the piedmont zone, especially when the rugged surface and the widespread limestone outcrop appear simultaneously. Finally, we have developed some potential needs of seismic theories and techniques in the foothill belt, including seismic wave propagation, acquisition, and processing technology.

SH wave propagation by discrete wavenumber boundary integral modeling in transversely isotropic medium

1996 ◽  
Vol 86 (2) ◽  
pp. 524-529
Author(s):  
Hayrullah Karabulut ◽  
John F. Ferguson
Keyword(s):  
Transversely Isotropic ◽  
Boundary Integral ◽  
Boundary Integral Method ◽  
Interface Problem ◽  
Seismic Profiles ◽  
Sh Waves ◽  
Vertical Seismic Profiles ◽  
Flat Interface ◽  
Transversely Isotropic Media ◽  
Isotropic Media

Abstract An extension of the boundary integral method for SH waves is given for transversely isotropic media. The accuracy of the method is demonstrated for a simple flat interface problem by comparison to the Cagniard-de Hoop solution. The method is further demonstrated for a case with interface topography for both surface and vertical seismic profiles. The new method is found to be both accurate and effective.

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