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1
Gaiser, James E., Terrance J. Fulp, Steve G. Petermann, and Gary M. Karner. "Vertical seismic profile sonde coupling." GEOPHYSICS 53, no. 2 (February 1988): 206–14. http://dx.doi.org/10.1190/1.1442456.
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P-wave and S-wave displacements occur at high angles of incidence in vertical seismic profiles (VSPs). Therefore, the coupling of a geophone sonde to the borehole wall must be rigid in all directions. A sonde that is well coupled should have no resonant frequency within the seismic band and should provide geophone outputs that accurately represent the earth’s ground motion. An in‐situ coupling response experiment conducted under normal VSP field conditions provides a measure of the sonde‐to‐borehole wall coupling. The sonde is locked in the borehole and a surface source is excited at different offsets and azimuths. An analysis of the P-wave direct arrivals enhances damped oscillations that represent an estimate of the coupling impulse response. This response is characterized by the viscoelastic behavior of a Kelvin model related to the complex compliance [Formula: see text], where κ is the elastic spring constant, η is the damping constant, and ω is the angular frequency. The complex modulus κ−iωη is proportional to the contact width of the sonde with the borehole wall. Increasing the width by a factor of 4.5 causes a similar increase in κ−iωη where the resonant frequency and initial amplitude of the coupling impulse response increase by a factor of two. Also, the initial amplitude of the coupling impulse response appears to be inversely proportional to the locking force of the sonde. For a constant contact width, increasing the locking force by a factor of 1.37 decreases the amplitude of the response by 3.5 dB.
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Amini, Navid, and Hamed Amini. "Vertical seismic profile waveform inversion." Studia Geophysica et Geodaetica 59, no. 2 (March 23, 2015): 283–93. http://dx.doi.org/10.1007/s11200-013-1252-5.
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Marl, J. L., Christian Wittrisch, Raoul Goepfer, and A. M. Spreux. "Vertical Seismic Profile in Horizontal Wells." Journal of Petroleum Technology 42, no. 12 (December 1, 1990): 1486–93. http://dx.doi.org/10.2118/19856-pa.
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Ross, W. S., and P. M. Shah. "Vertical seismic profile reflectivity: Ups over downs." GEOPHYSICS 52, no. 8 (August 1987): 1149–54. http://dx.doi.org/10.1190/1.1442379.
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The idea of designing a deconvolution operator for the vertical seismic profile (VSP) based on its downgoing waves is well known (Anstey, 1976; Gaiser et al., 1984; Hubbard, 1979; Lee and Balch, 1983; Kennett et al., 1980). Many variations of the scheme exist. Anstey (1976) recommends the average of the downgoing wave from all levels as the basis for designing an inverse operator. Lee and Balch (1983) use the downgoing wave from a single level to deconvolve all the VSP traces. Gaiser et al. (1984) and Hubbard (1979) recommend doing the deconvolution independently at each depth level. As observed by Hubbard, there are similar disparities in the literature about whether all or only part of the downgoing wave train should be used in the design of an inverse operator. Although all of the above approaches are identical if multiples are generated in a limited zone near the sea bottom, they differ for more complex media. We recommend, and in this note we explore the theoretical properties of, the level‐by‐level deconvolution based on the entire downgoing wave train. The expressions we develop apply to the general case of the vertical VSP response to any number of horizontal layers with any degree of complexity in the process that generates multiples.
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Nolte, B., and L. N. Frazer. "Vertical Seismic Profile Inversion With Genetic Algorithms." Geophysical Journal International 117, no. 1 (April 1994): 162–78. http://dx.doi.org/10.1111/j.1365-246x.1994.tb03310.x.
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Lomas, Angus, Satyan Singh, and Andrew Curtis. "Imaging vertical structures using Marchenko methods with vertical seismic-profile data." GEOPHYSICS 85, no. 2 (February 12, 2020): S103—S113. http://dx.doi.org/10.1190/geo2018-0698.1.
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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.
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Grivelet, Pierre A. "Inversion of vertical seismic profiles by iterative modeling." GEOPHYSICS 50, no. 6 (June 1985): 924–30. http://dx.doi.org/10.1190/1.1441971.
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I present an application of iterative modeling to the inversion of vertical seismic profiles (VSPs). This method is derived from linear inversion which allows the extraction from VSP data of an impedance profile as a function of time and thus permits the prediction of impedance ahead of the drill bit. There are two steps in this process: first, detection of the major events on the seismogram which is achieved by a recursive detection algorithm; and second, an optimal estimate of the impedances carried out by a gradient algorithm. Seismic data are band‐limited, and consequently the solution of the inversion is nonunique. This nonuniqueness is handled by assuming a piecewise‐constant or blocked impedance model and by adding a priori constraints. Some synthetic examples are used to illustrate the method, and a field example shows a comparison between an impedance profile extracted from VSP data with this inversion method and an impedance profile from well logging data. In this example the accurate prediction of impedance values illustrates the usefulness of the method.
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Yu, Jianhua, and Gerard T. Schuster. "Crosscorrelogram migration of inverse vertical seismic profile data." GEOPHYSICS 71, no. 1 (January 2006): S1—S11. http://dx.doi.org/10.1190/1.2159056.
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We present the theory of crosscorrelogram migration of ghost reflections, also known as interferometric imaging, to delineate reflector geometries from inverse vertical seismic profile data. The theory includes the equations for forward modeling, migration, asymptotic inversion, and model resolution of crosscorrelgrams. Rather than using primary reflections, crosscorrelogram migration can use ghost reflections to reconstruct the reflector geometry. Other multiples can be used as well, including pegleg multiples and higher-order multiples. Its main advantages over conventional Kirchhoff migration are (1) both source location (e.g., drill-bit position) and source wavelet need not be known (such as when using a drill bit as a source in a deviated well), (2) it is insensitive to source-related static errors, and (3) it has wider subsurface illumination than conventional Kirchhoff migration of primary reflections. Crosscorrelation migration can effectively widen the source-receiver aperture by more than 50% compared to standard inverse vertical seismic profile (IVSP) migration. The primary disadvantages are (1) it uses ghost reflections for imaging, which can be weaker (or sometimes more distorted) than primary reflections; (2) crosscorrelation creates virtual multiples that can sometimes appear as coherent noise in the final image; and (3) it has poorer horizontal resolution than standard IVSP migration. Results from imaging simulated IVSP traces show that crosscorrelation migration produces reflectivity-like images that correlate well with the actual reflector geometry of a layered fault model. These images are almost completely immune to static errors at the source location and have wider subsurface illumination than conventional IVSP migration images. We also apply crosscorrelation migration to IVSP data recorded at a Friendswood, Texas, test site. Results show that the crosscorrelation image correlates better with the well log and wider subsurface illumination than a conventional Kirchhoff migration image.
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AMUNDSEN, LASSE, BORGE ARNTSEN, and RUNE MITTET. "DEPTH IMAGING OF OFFSET VERTICAL SEISMIC PROFILE DATA1." Geophysical Prospecting 41, no. 8 (November 1993): 1009–31. http://dx.doi.org/10.1111/j.1365-2478.1993.tb00896.x.
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Huang, Yunsong, Ruiqing He, Chaiwoot Boonyasiriwat, Yi Luo, and Gerard Schuster. "Specular interferometric imaging of vertical seismic profile data." Interpretation 3, no. 3 (August 1, 2015): SW57—SW62. http://dx.doi.org/10.1190/int-2014-0251.1.
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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.
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Dillon, P. B. "Vertical seismic profile migration using the Kirchhoff integral." GEOPHYSICS 53, no. 6 (June 1988): 786–99. http://dx.doi.org/10.1190/1.1442514.
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Wave‐equation migration can form an accurate image of the subsurface from suitable VSP data. The image’s extent and resolution are determined by the receiver array dimensions and the source location(s). Experiments with synthetic and real data show that the region of reliable image extent is defined by the specular “zone of illumination.” Migration is achieved through wave‐field extrapolation, subject to an imaging procedure. Wave‐field extrapolation is based upon the scalar wave equation and, for VSP data, is conveniently handled by the Kirchhoff integral. The migration of VSP data calls for imaging very close to the borehole, as well as imaging in the far field. This dual requirement is met by retaining the near‐field term of the integral. The complete integral solution is readily controlled by various weighting devices and processing strategies, whose worth is demonstrated on real and synthetic data.
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Dillon, William G., and Terry W. Spencer. "Improved interface detection for vertical seismic profile inversion." GEOPHYSICS 53, no. 9 (September 1988): 1244–47. http://dx.doi.org/10.1190/1.1442566.
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Grivelet (1985) presented an interface detection scheme as part of his iterative modeling approach to vertical seismic profile (VSP) inversion. In his scheme and those like it (Dillon, 1985), the interfaces which produce major reflections must be identified for reasons of stability and uniqueness. In general, Grivelet’s detection algorithm works well, though it sometimes fails when two events of the same polarity and amplitude overlap. By extending his detection algorithm, we obtain more robust interface detection.
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Zimmerman, Linda J., and Sen T. Chen. "Comparison of vertical seismic profiling techniques." GEOPHYSICS 58, no. 1 (January 1993): 134–40. http://dx.doi.org/10.1190/1.1443343.
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To study the imaging characteristics of various vertical seismic profiling techniques, two vertical seismic profiles (VSP) and a reversed vertical seismic profile (RVSP), where source and receiver positions are interchanged, were collected in the Loudon Oil Field in Illinois. Both VSPs were collected using a line of dynamite charges on the surface as sources. One was collected with geophones and the other with hydrophones as downhole receivers. The RVSP was collected by detonating 25 gram explosive charges in a well and detecting the seismic response with geophones at the surface. Three subsurface images (VSP with geophones, VSP with hydrophones, and RVSP) were produced using VSP-CDP transforms. For comparison, a surface seismic profile was collected along the same line with dynamite sources and vertical geophone receivers. The RVSP and hydrophone VSP stacked sections both produced higher frequency images at shallower depths than did the geophone VSP stacked section. However, the lower frequency geophone VSP stacked section produced an interpretable subsurface image at much greater depths than either the RVSP or the hydrophone VSP sections. The differences are due in part to the more powerful surface sources that were used for the VSPs than the downhole sources used for the RVSP. Furthermore, tube‐wave noise was a more severe problem for both the RVSP and the hydrophone VSP than for the geophone VSP. The results of this experiment demonstrate that if tube‐wave noise could be suppressed, hydrophone VSPs would provide attractive alternatives to geophone VSPs, because it is much easier and cheaper to deploy multilevel hydrophones downhole than geophones. Also, if a high‐powered, nondestructive source is developed, RVSP could be a practical alternative to VSP since one can easily lay out numerous receivers on the surface to record multioffset or three‐dimensional (3-D) VSP data.
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Winterstein, D. F., and B. N. P. Paulsson. "Velocity anisotropy in shale determined from crosshole seismic and vertical seismic profile data." GEOPHYSICS 55, no. 4 (April 1990): 470–79. http://dx.doi.org/10.1190/1.1442856.
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Crosshole and vertical seismic profile (VST) data made possible accurate characterization of the elastic properties, including noticeable velocity anisotropy, of a near‐surface late Tertiary shale formation. Shear‐wave splitting was obvious in both crosshole and VSP data. In crosshole data, two orthologonally polarrized shear (S) waves arrived 19 ms in the uppermost 246 ft (75 m). Vertically traveling S waves of the VSP separated about 10 ms in the uppermost 300 ft (90 m) but remained at nearly constant separation below that level. A transversely isotropic model, which incorporates a rapid increase in S-wave velocities with depth but slow increase in P-wave velocities, closely fits the data over most of the measured interval. Elastic constants of the transvesely isotropic model show spherical P- and [Formula: see text]wave velocity surfaces but an ellipsoidal [Formula: see text]wave surface with a ratio of major to minor axes of 1.15. The magnitude of this S-wave anisotropy is consistent with and lends credence to S-wave anisotropy magnitudes deduced less directly from data of many sedimentary basins.
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Larsen, Anne Louise, Marit Ulvmoen, Henning Omre, and Arild Buland. "Bayesian lithology/fluid prediction and simulation on the basis of a Markov-chain prior model." GEOPHYSICS 71, no. 5 (September 2006): R69—R78. http://dx.doi.org/10.1190/1.2245469.
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A technique for lithology/fluid (LF) prediction and simulation from prestack seismic data is developed in a Bayesian framework. The objective is to determine the LF classes along 1D profiles through a reservoir target zone. A stationary Markov-chain prior model is used to model vertical continuity of LF classes along the profile. The likelihood relates the LF classes to the elastic properties and to the seismic data, and it introduces vertical correlation because the seismic data are band-limited. An approximation of the likelihood model provides an approximate posterior model that is a Markov chain. The approximate posterior can be assessed by an exact and efficient recursive algorithm. The LF inversion approach is evaluated on a synthetic 1D profile that is inspired by a North Sea sandstone reservoir. With a realistic wavelet-colored noise model and a S/N ratio of three in the seismic data, the results are reliable. The LF classes and the interfaces between zones are largely correct. The prediction uncertainty increases if the number of zones increases and zone thicknesses decreases. The study clearly demonstrates the impact of a vertically coupled prior Markov model for the LF classes.
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Boulfoul, M., and Doyle R. Watts. "Application of instantaneous rotations to S‐wave vertical seismic profiling." GEOPHYSICS 62, no. 5 (September 1997): 1365–68. http://dx.doi.org/10.1190/1.1444240.
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The petroleum exploration industry uses S‐wave vertical seismic profiling (VSP) to determine S‐wave velocities from downgoing direct arrivals, and S‐wave reflectivities from upgoing waves. Seismic models for quantitative calibration of amplitude variation with offset (AVO) data require S‐wave velocity profiles (Castagna et al., 1993). Vertical summations (Hardage, 1983) of the upgoing waves produce S‐wave composite traces and enable interpretation of S‐wave seismic profile sections. In the simplest application of amplitude anomalies, the coincidence of high amplitude P‐wave reflectivity and low amplitude S‐wave reflectivity is potentially a direct indicator of the presence of natural gas.
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Zhao, Xiaomin, and Shengwen Jin. "Vertical seismic profile Kirchhoff migration with structure dip constraint." Interpretation 3, no. 3 (August 1, 2015): SW51—SW56. http://dx.doi.org/10.1190/int-2014-0240.1.
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Prestack Kirchhoff depth migration is commonly used in borehole seismic imaging, where there is uneven illumination due to the limitations of the source-receiver geometry. A new vertical seismic profile (VSP) migration/imaging workflow has been established that incorporates the structure-dip information derived from a newly developed structure tensor analysis into the existing VSP Kirchhoff migration/imaging technique. This allows us to better image the structures in the vicinity of a borehole and the far-field dipping events away from the borehole. We tested the workflow with the HESS salt model. The results were compared with those from reverse time migration, which found that Kirchhoff migration combined with structure-dip information not only reduced ambiguities of the imaging result but also allowed for imaging dip structures (e.g., fault) in the far region from the borehole. This allows for imaging dip structures and provides a useful extension of existing VSP imaging capabilities using Kirchhoff migration.
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Spencer, Terry W., Gregory A. Smith, and Woon Hyun Cho. "Vertical seismic profile polarization method for determining reflector orientation." GEOPHYSICS 53, no. 9 (September 1988): 1169–74. http://dx.doi.org/10.1190/1.1442556.
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The strike and dip of the reflecting interfaces in the vicinity of a well can be derived from VSP data recorded with a three‐component downhole seismometer. The method relies on measuring the polarizations in the direct and reflected compressional waves. The mathematical relation which is the basis of the method is exact only when the seismometer is positioned at the depth where the interface intersects the well. At that depth the polarization of the reflected wave cannot be measured because of interference with the direct wave. The orientation of the normal to the reflector can be determined to within 2° when the polarizations of the direct and reflected waves are determined within 100 m of the reflector. If the direct and reflected waves can be identified without multidepth processing, only measurements at a single depth are required to determine the reflector orientation. Error analysis and statistical refinement can be achieved by measuring the polarizations at several seismometer depths, source azimuths, or source offsets. The method is robust in the sense that the error in the interface orientation cannot exceed the error in the measurement of the polarizations. The method should be useful in structurally complex areas provided the reflections can be observed at depths above the depths of generation.
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Shi, Ying, and Yanghua Wang. "Reverse time migration of 3D vertical seismic profile data." GEOPHYSICS 81, no. 1 (January 1, 2016): S31—S38. http://dx.doi.org/10.1190/geo2015-0277.1.
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Reverse time migration (RTM) has shown increasing advantages in handling seismic images of complex subsurface media, but it has not been used widely in 3D seismic data due to the large storage and computation requirements. Our prime objective was to develop an RTM strategy that was applicable to 3D vertical seismic profiling (VSP) data. The strategy consists of two aspects: storage saving and calculation acceleration. First, we determined the use of the random boundary condition (RBC) to save the storage in wavefield simulation. An absorbing boundary such as the perfect matching layer boundary is often used in RTM, but it has a high memory demand for storing the source wavefield. RBC is a nonabsorbing boundary and only stores the source wavefield at the two maximum time steps, then repropagates the source wavefield backwards at every time step, and hence, it significantly reduces the memory requirement. Second, we examined the use of the graphic processing unit (GPU) parallelization technique to accelerate the computation. RBC needs to simulate the source wavefield twice and doubles the computation. Thus, it is very necessary to realize the RTM algorithm by GPU, especially for a 3D VSP data set. GPU and central processing unit (CPU) collaborated parallel implementation can greatly reduce the computation time, where the CPU performs serial code, and the GPU performs parallel code. Because RBC does not need the same huge amount of storage as an absorbing boundary, RTM becomes practically applicable for 3D VSP imaging.
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Vignoli, Giulio, Rita Deiana, and Giorgio Cassiani. "Focused inversion of vertical radar profile (VRP) traveltime data." GEOPHYSICS 77, no. 1 (January 2012): H9—H18. http://dx.doi.org/10.1190/geo2011-0147.1.
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The reconstruction of the GPR velocity vertical profile from vertical radar profile (VRP) traveltime data is a problem with a finite number of measurements and imprecise data, analogous to similar seismic techniques, such as the shallow down-hole test used for S-wave velocity profiling or the vertical seismic profiling (VSP) commonly used in deeper exploration. The uncertainty in data accuracy and the error amplification inherent in deriving velocity estimates from gradients of arrival times make this an example of an ill-posed inverse problem. In the framework of Tikhonov regularization theory, ill-posedness can be tackled by introducing a regularizing functional (stabilizer). The role of this functional is to stabilize the numerical solution by incorporating the appropriate a priori assumptions about the geometrical and/or physical properties of the solution. One of these assumptions could be the existence of sharp boundaries separating rocks with different physical properties. We apply a method based on the minimum support stabilizer to the VRP traveltime inverse problem. This stabilizer makes it possible to produce more accurate profiles of geological targets with compact structure. We compare more traditional inversion results with our proposed compact reconstructions. Using synthetic examples, we demonstrate that the minimum support stabilizer allows an improved recovery of the profile shape and velocity values of blocky targets. We also study the stabilizer behavior with respect to different noise levels and different choices of the reference model. The proposed approach is then applied to real cases where VPRs have been used to derive moisture content profiles as a function of depth. In these real cases, the derived sharper profiles are consistent with other evidence, such as GPR zero-offset profiles, GPR reflections and known locations of the water table.
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Haldorsen, Jakob B. U., Douglas E. Miller, and John J. Walsh. "Multichannel Wiener deconvolution of vertical seismic profiles." GEOPHYSICS 59, no. 10 (October 1994): 1500–1511. http://dx.doi.org/10.1190/1.1443540.
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We describe a technique for performing optimal, least‐squares deconvolution of vertical seismic profile (VSP) data. The method is a two‐step process that involves (1) estimating the source signature and (2) applying a least‐squares optimum deconvolution operator that minimizes the noise not coherent with the source signature estimate. The optimum inverse problem, formulated in the frequency domain, gives as a solution an operator that can be interpreted as a simple inverse to the estimated aligned signature multiplied by semblance across the array. An application to a zero‐offset VSP acquired with a dynamite source shows the effectiveness of the operator in attaining the two conflicting goals of adaptively spiking the effective source signature and minimizing the noise. Signature design for seismic surveys could benefit from observing that the optimum deconvolution operator gives a flat signal spectrum if and only if the seismic source has the same amplitude spectrum as the noise.
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Hu, Liang‐Zie, and George A. McMechan. "Wave‐field transformations of vertical seismic profiles." GEOPHYSICS 52, no. 3 (March 1987): 307–21. http://dx.doi.org/10.1190/1.1442305.
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Vertical seismic profile (VSP) data may be partitioned in a variety of ways by application of wave‐field transformations. These transformations provide insights into the nature of the data and aid in the design of processing operations. Transformations are implemented in a reversible sequence that takes the observed VSP data from the depth‐time (z-t) domain through the slowness‐time intercept (p-τ) domain (by a slant stack), to the slowness‐frequency (p-ω) domain (by a 1-D Fourier transform over τ), to the wavenumber‐frequency (k-ω) domain (by resampling using the Fourier central‐slice theorem), and finally back to the z-t domain (by an inverse 2-D Fourier transform). Multidimensional wave‐field transformations, combined with k-ω, p-ω, and p-τ filtering, can be applied to wave‐field resampling, interpolation, and extrapolation; separation of P-waves and S-waves; separation of upgoing and downgoing waves; and wave‐field decomposition for isolation, identification, and analysis of arrivals.
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Carr, B. J., S. B. Smithson, N. Kareav, A. Ronin, V. Garipov, Y. Kristofferson, P. Digranes, D. Smythe, and C. Gillen. "Vertical seismic profile results from the Kola Superdeep Borehole, Russia." Tectonophysics 264, no. 1-4 (October 1996): 295–307. http://dx.doi.org/10.1016/s0040-1951(96)00133-3.
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Dean, Tim, Nghia Nguyen, Brenton Armitage, and Huw Rossiter. "A new system surveys for efficiently acquiring vertical seismic profile." ASEG Extended Abstracts 2018, no. 1 (December 2018): 1–8. http://dx.doi.org/10.1071/aseg2018abt5_2c.
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Willis, Mark E., David Barfoot, Andreas Ellmauthaler, Xiang Wu, Oscar Barrios, Cemal Erdemir, Simon Shaw, and Dan Quinn. "Quantitative quality of distributed acoustic sensing vertical seismic profile data." Leading Edge 35, no. 7 (July 2016): 605–9. http://dx.doi.org/10.1190/tle35070605.1.
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Snyder, David, Gervais Perron, Karen Pflug, and Kevin Stevens. "New insights into the structure of the Sudbury Igneous Complex from downhole seismic studies." Canadian Journal of Earth Sciences 39, no. 6 (June 1, 2002): 943–51. http://dx.doi.org/10.1139/e02-013.
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New vertical seismic profiles from the northwest margin of the Sudbury impact structure provide details of structural geometries within the lower impact melt sheet (usually called the Sudbury Igneous Complex) and the sublayer norite layer. Vertical seismic profile sections and common depth point transformation images display several continuous reflections that correlate with faults and stratigraphic boundaries logged from drill cores. Of four possible mechanisms that explain repeated rock units, late-stage flow or normal faulting that occurred within the last layers to cool and crystallize might best explain the observations, especially the most prominent reflectors observed in the seismic data. These results reaffirm previously proposed two-stage cooling and deformation models for the impact melt sheet.
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IOANNIS, I. F. "Prospecting for voids with vertical radar profiling." Bulletin of the Geological Society of Greece 34, no. 4 (January 1, 2001): 1363. http://dx.doi.org/10.12681/bgsg.17229.
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Vertical Radar Profiling measurements were conducted to image subsurface cavities encountered in Akrotiri Archaeological Excavations area on Thera Island. The vertical radar profiling technique is able to explore much deeper than conventional surface GPR because it uses wells. The transmitting-receiving antenna unit was moved within the excavated well along six vertical profile lines in equally divided positions. A local electrical resistivity survey preceded the GPR profiles to investigate if the conductivity of the pyroclastic formation satisfies the presuppositions to conduct GPR measurements. The vertical GPR profiles revealed locations where cavities exist but they were unable to show their shape and extent. Cross-well seismic tomography images supported the vertical radar profiling results.
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Baharvand Ahmadi, Amin, and Igor Morozov. "Anisotropic frequency-dependent spreading of seismic waves from first-arrival vertical seismic profile data analysis." GEOPHYSICS 78, no. 6 (November 1, 2013): C41—C52. http://dx.doi.org/10.1190/geo2012-0401.1.
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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.
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Benaïssa, Abdelkader, Zahia Benaïssa, Tahar Aïfa, and Amar Boudella. "Filtrage par reconnaissance des formes d’un profil sismique vertical Vertical seismic profile filtering through the use of pattern recognition." Swiss Journal of Geosciences 102, no. 2 (July 27, 2009): 297–306. http://dx.doi.org/10.1007/s00015-009-1324-2.
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Sun, Robert, and George A. McMechan. "Nonlinear reverse‐time inversion of elastic offset vertical seismic profile data." GEOPHYSICS 53, no. 10 (October 1988): 1295–302. http://dx.doi.org/10.1190/1.1442407.
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An iterative nonlinear inversion algorithm for two‐dimensional elastic media gives estimates of P-velocity and S-velocity distributions from synthetic offset vertical seismic profiles. The algorithm is a hybrid of inversion and principles borrowed from reverse‐time migration. Gradients of the misfit function are dynamically determined by crosscorrelations of the computed incident wave fields with the scattered compressional and shear wave fields. Model perturbations are defined in the steepest descent direction. In order to optimize the sensitivity of the inversion to both compressional and shear velocity distributions, two data collection experiments are required, one with a compressional wave source and the other with a shear wave source. Inversion iterations alternate between the compressional and shear source data sets. In test examples, the new algorithm converges successfully to the correct solution when the starting model’s compressional and shear velocities deviated by as much as 20 percent from the correct solution.
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Shafiq, Muhammad, Konstantin Galybin, and Mehdi Asgharzadeh. "Look Ahead Rig Source Vertical Seismic Profile (VSP) Applications - Case Studies." ASEG Extended Abstracts 2015, no. 1 (December 2015): 1–3. http://dx.doi.org/10.1071/aseg2015ab148.
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Pujol, J., B. N. Fuller, and S. B. Smithson. "Interpretation of a vertical seismic profile conducted in the Columbia Plateau basalts." GEOPHYSICS 54, no. 10 (October 1989): 1258–66. http://dx.doi.org/10.1190/1.1442585.
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Seismic reflection data are often of poor quality when recorded in areas where volcanic rocks are present at or near the surface. In order to investigate this phenomenon, a vertical seismic profiling (VSP) experiment was conducted in the Columbia Plateau basalts so that the behavior of seismic energy in subsurface volcanic rocks could be observed directly, thus giving insight into data acquisition in volcanic terrains. The lithologic section at the VSP site consists of low‐velocity (400 m/s to 900 m/s) alluvium in the uppermost 50 m, beneath which are layers of high‐velocity (about 5800 m/s), high‐density basalts interbedded with clay layers with much lower velocities (about 1700 m/s) and densities. These large velocity and density contrasts dramatically influence wave generation and propagation. In spite of the small source‐borehole offset (61 m), large‐amplitude S waves are generated by the downgoing P waves when they reach a shallow (250 m) clay‐basalt boundary. These S waves, in turn, generate strong reflected P waves when they interact with another clay layer at 500 m. On the other hand, strong primary P‐wave reflections are also present in the data but are affected by various interfering effects which reduce their amplitudes. The VSP data are also characterized by large‐amplitude reverberations caused by seismic energy trapped in the upper 250 m of the lithologic section. Reverberations are also observed in surface data recorded near the VSP site. We conclude from our analysis that volcanic rocks, at least in the Columbia Plateau, do not exhibit unusual energy transmission characteristics and that the observations can be explained in terms of the large contrast in the elastic properties of interbedded clay and basalt.
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Winterstein, D. F., and G. S. De. "VTI documented." GEOPHYSICS 66, no. 1 (January 2001): 237–45. http://dx.doi.org/10.1190/1.1444900.
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Shear‐wave (S‐wave) seismic data indicate that rocks of McElroy oil field on the Central Basin Platform of West Texas are transversely isotropic with a vertical symmetry axis (VTI). Although geophysicists from time to time had anticipated or assumed that sedimentary rock was VTI, no one had shown that any sedimentary section actually was VTI. The proof at McElroy comes from a nine‐component, near‐offset vertical seismic profile (VSP) combined with a ring of 15 offset VSPs spaced about 24° apart at offsets of about 460 m. S-wave splitting at VSP frequencies was negligible for vertical propagation to a depth of 885 m but reached about 12 ms for nonvertical propagation from the offset source locations. Crossed‐dipole log data supported the VSP result for vertical propagation but found two layers of vertically birefringent rock at depth whose thicknesses were below VSP resolution.
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Hu, Liang-Zie, George A. McMechan, and Jerry M. Harris. "Elastic finite-difference modeling of cross-hole seismic data." Bulletin of the Seismological Society of America 78, no. 5 (October 1, 1988): 1796–806. http://dx.doi.org/10.1785/bssa0780051796.
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Abstract Cross-hole seismic data exhibit unique characteristics not seen in surface survey data or even in vertical seismic profile data. These are, to a large extent, due to the near-horizontal propagation involved. Transmitted, reflected, evanescent, guided, and converted waves are all prominent; these require an elastic algorithm for realistic simulation. Elastic finite-differences are used to synthesize responses (both fixed-time snapshots and seismogram profiles) for a series of two-dimensional models of increasing complexity. Special emphasis is given to guided waves in continuous and segmented low-velocity zones.
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Ouzandja, Toufiq, and Mohamed Hadid. "Sensitivity analysis of geotechnical site conditions effect on the seismic response of a saturated inhomogeneous poroviscoelastic soil profile." World Journal of Engineering 15, no. 6 (December 3, 2018): 661–77. http://dx.doi.org/10.1108/wje-12-2017-0388.
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Purpose This paper aims to present the investigation of the linear and nonlinear seismic site response of a saturated inhomogeneous poroviscoelastic soil profile for different soil properties, such as pore-water saturation, non-cohesive fines content FC, permeability k, porosity n and coefficient of uniformity Cu. Design/methodology/approach The inhomogeneous soil profile is idealized as a multi-layered saturated poroviscoelastic medium and is characterized by the Biot’s theory, with a shear modulus varying continuously with depth according to the Wichtmann’s model. Seismic response analysis has been evaluated through a computational model, which is based on the exact stiffness matrix method formulated in the frequency domain assuming that the incoming seismic waves consist of inclined P-SV waves. Findings Unlike the horizontal seismic response, the results indicate that the vertical one is strongly affected by the pore water saturation. Moreover, in the case of fully saturated soil profile, the same vertical response spectra are found for the two cases of soil behavior, linear and nonlinear. Originality/value This research is a detailed study of the geotechnical soil properties effect on the bi-directional seismic response of saturated inhomogeneous poroviscoelastic soil profile, which has not been treated before; the results are presented in terms of the peak acceleration ratio, as well as the free-field response spectra and the spectral ratio (V/H).
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Roksandic, Miodrag M. "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 59, no. 7 (July 1994): 1171. http://dx.doi.org/10.1190/1.1443674.
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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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Hinds, Ronald C., Neil L. Anderson, and Richard Kuzmiski. "An integrated surface seismic/seismic profile case study: Simonette area, Alberta." GEOPHYSICS 58, no. 11 (November 1993): 1676–88. http://dx.doi.org/10.1190/1.1443383.
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On the basis of conventional surface seismic data, the 13–15–63–25W5M exploratory well was drilled into a low‐relief Leduc Formation reef (Devonian Woodbend Group) in the Simonette area, west‐central Alberta, Canada. The well was expected to intersect the crest of the reef and encounter about 50–60 m of pay; unfortunately it was drilled into a flank position and abandoned. The decision to abandon the well, as opposed to whipstocking in the direction of the reef crest, was made after the acquisition and interpretive processing of both near( and far‐offset (252 and 524 m, respectively) vertical seismic profile (VSP) data, and after the reanalysis of existing surface seismic data. The near‐ and far‐offset VSPs were run and interpreted while the drill rig remained on‐site, with the immediate objectives of: (1) determining an accurate tie between the surface seismic data and the subsurface geology; and (2) mapping relief along the top of the reef over a distance of 150 m from the 13–15 well location in the direction of the adjacent productive 16–16 well (with a view to whipstocking). These surveys proved to be cost‐effective in that the operators were able to determine that the crest of the reef was out of the target area, and that whipstocking was not a viable alternative. The use of VSP surveys in this situation allowed the operators to avoid the costs associated with whipstocking, and to feel confident with their decision to abandon the well.
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Li, Yandong, and Bob A. Hardage. "SV-P extraction and imaging for far-offset vertical seismic profile data." Interpretation 3, no. 3 (August 1, 2015): SW27—SW35. http://dx.doi.org/10.1190/int-2015-0002.1.
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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.
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Mallick, Subhashis, and L. Neil Frazer. "Rapid computation of multioffset vertical seismic profile synthetic seismograms for layered media." GEOPHYSICS 53, no. 4 (April 1988): 479–91. http://dx.doi.org/10.1190/1.1442479.
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By rearranging the formulas for the responses of buried sources and receivers in the Kennett reflectivity algorithm, we have obtained a new algorithm that is very efficient for computing multioffset VSP synthetic seismograms. The rearrangement of the response formulas is quite general inasmuch as it applies to both isotropic and anisotropic Kennett codes. Our new algorithm and the original single‐receiver algorithm can both be made to run much faster on vector computers by taking the layer loop out of the p-loop, but leaving it inside the frequency loop. The resulting vector codes can still compute the response of media with frequency‐ dependent velocities.
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DADLEZ, RYSZARD. "Seismic profile LT-7 (northwest Poland): geological implications." Geological Magazine 134, no. 5 (September 1997): 653–59. http://dx.doi.org/10.1017/s0016756897007401.
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Crystalline crust examined along the seismic profile LT-7 is subdivided into four blocks separated by distinct vertical fractures. The northeastern block belongs to the East European Craton (Baltica). Its three-layer structure is similar to that of the Svecofennian crust farther to the northwest. The southeastern block reveals typical, two-layer Variscan crust. Both central blocks have a peculiar structure not comparable with the crust of the Danish and North German areas: two lower layers, with velocities identical or close to that of the cratonic lower and middle layers, are extremely thin, and an upper layer, 8–11 km thick, shows surprisingly low velocities. This upper layer probably represents the folded and weakly metamorphosed Lower Palaeozoic sequences, although the connection with undeformed epicratonic cover cannot be excluded. Significant differentiation of crustal types in different segments of the Trans-European Suture Zone favours the concept of tectonostratigraphic terranes which collided with Baltica.
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Gulati, Jitendra S., Robert R. Stewart, and John M. Parkin. "Analyzing three‐component 3D vertical seismic profiling data." GEOPHYSICS 69, no. 2 (March 2004): 386–92. http://dx.doi.org/10.1190/1.1707057.
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A three‐component 3D vertical seismic profile (VSP) was acquired over the Blackfoot oil field in Alberta, Canada. The VSP survey was recorded simultaneously with a surface seismic program. The objectives of the VSP were to develop recording logistics, data handling, and processing procedures and to determine if the 3D VSP volumes could image the glauconitic sand reservoir of the Blackfoot field. Dynamite shots from the surface seismic survey, which fell within a 2200‐m offset from the recording well, were used in the VSP analysis. The shots were recorded by a string of three‐component borehole receivers that was moved seven times, resulting in a receiver depth range of 400 to 910 m. The borehole data were processed using basic VSP processing techniques that included hodogram analysis, wavefield separation using median filters, and VSP deconvolution. The final P‐P and P‐S image volumes were obtained by VSP common‐depth point and VSP common‐conversion point stacking the upgoing wavefields followed by f‐xy deconvolution. The P‐P and P‐S images from the VSP correlate well with those from the surface seismic survey. Time slices from the VSP also indicate the trend of the sand channel of the Blackfoot field.
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Takam Takougang, Eric M., and Youcef Bouzidi. "Imaging high-resolution seismic velocity from walkaway vertical seismic profile data in a carbonate reservoir using acoustic waveform tomography." GEOPHYSICS 83, no. 3 (May 1, 2018): B77—B85. http://dx.doi.org/10.1190/geo2017-0180.1.
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High-resolution seismic velocity was obtained using acoustic full-waveform tomography of walkaway vertical seismic profile (VSP) data from an oil field dominated by carbonate rocks, offshore Abu Dhabi in the United Arab Emirates. The data were collected in a deviated borehole with receivers located from 521 to 2742 m depth. The inversion was performed in the frequency domain. The success of the inversion was determined by three important factors: the starting model, the preconditioning of the input data, and the inversion strategy, which included an appropriate selection of a damping term [Formula: see text] in the Laplace–Fourier transformation. The inversion was performed between the frequencies of 4 and 50 Hz, and a logarithmic data residual was used. The extracted 1D velocity profiles from the final high-resolution velocity model correlate well with the sonic log, and estimated vertical incidence VSP velocities. The predicted data obtained by the final velocity model indicate a generally good fit with the field data, thus confirming the success of the inversion. A reverse time migrated section derived by the final velocity model provides additional structural details. The velocity model indicates anomalous zones of low-velocity values that correlate with known locations of hydrocarbon reservoirs.
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McMechan, George A. "Synthetic finite‐offset vertical seismic profiles for laterally varying media." GEOPHYSICS 50, no. 4 (April 1985): 627–36. http://dx.doi.org/10.1190/1.1441938.
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The analysis of vertical seismic profile (VSP) data is generally directed toward determination of rock properties (such as velocity, impedance, attenuation, and anisotropy) as functions of depth (that is, in a one‐dimensional model). If VSPs are extended to include observations from sources at multiple, finite offsets, then lateral variation in structure near the drill hole can be studied. Synthetic offset VSPs are computed by an acoustic finite‐difference algorithm for two‐dimensional models that include the main types of structural traps. These show that diagnostic lateral variations can be detected and interpreted in VSPs. In a VSP, lateral structure variations may produce changes in the type and number of arrivals, in amplitudes, in time and phase shifts, in interference patterns, in curvature of arrival branches, and in the focusing and defocusing of energy. All of these effects are functions of the positions of the source(s) and receiver(s); numerical modeling is a potentially useful tool for interpretation of VSP data from laterally varying structure.
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Khedr, Mohamed A., and Ghyslaine McClure. "A simplified method for seismic analysis of lattice telecommunication towers." Canadian Journal of Civil Engineering 27, no. 3 (June 1, 2000): 533–42. http://dx.doi.org/10.1139/l99-090.
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A simplified static method for estimating the member forces in self-supporting lattice telecommunication towers due to both horizontal and vertical earthquake excitations is presented in this paper. The method is based on the modal superposition technique and the response spectrum approach, which are widely used for seismic analysis of linear structures. It is assumed that the lowest three flexural modes of vibration are sufficient to correctly estimate the tower's response to horizontal excitation, while only the lowest axial mode is sufficient to capture the response to vertical excitation. An acceleration profile along the height of the tower is defined using estimates of the lowest three flexural modes or the lowest axial mode, as appropriate, together with the spectral acceleration values corresponding to the associated natural periods. After the mass of the tower is calculated and lumped at the leg joints, a set of equivalent static lateral or vertical loads can be determined by simply multiplying the mass profile by the acceleration profile. The tower is then analyzed statically under the effect of these loads to evaluate the member forces. This procedure was developed on the basis of detailed dynamic analysis of ten existing three-legged self-supporting telecommunication towers with height range of 30-120 m. The maximum differences in member forces obtained with the proposed method and the detailed seismic analysis are of the order of ±25% in the extreme cases, with an average difference of ±7%. The results obtained for two towers with heights of 66 and 83 m are presented in this paper to demonstrate the accuracy and practicality of the proposed method.Key words: self-supporting tower, earthquake, vertical excitation, dynamic analysis.
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Egorov, Anton, Julia Correa, Andrej Bóna, Roman Pevzner, Konstantin Tertyshnikov, Stanislav Glubokovskikh, Vladimir Puzyrev, and Boris Gurevich. "Elastic full-waveform inversion of vertical seismic profile data acquired with distributed acoustic sensors." GEOPHYSICS 83, no. 3 (May 1, 2018): R273—R281. http://dx.doi.org/10.1190/geo2017-0718.1.
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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.
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Zaręba, Mateusz, and Tomasz Danek. "VSP polarization angles determination: Wysin-1 processing case study." Acta Geophysica 66, no. 5 (September 14, 2018): 1047–62. http://dx.doi.org/10.1007/s11600-018-0200-8.
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Abstract In this paper, we present an analysis of borehole seismic data processing procedures required to obtain high-quality vertical stacks and polarization angles in the case of walkaway VSP (vertical seismic profile) data gathered in challenging conditions. As polarization angles are necessary for more advanced procedures like anisotropy parameters determination, their quality is critical for proper media description. Examined Wysin-1 VSP experiment data indicated that the best results can be obtained when rotation is performed for each shot on data after de-noising and vertical stacking of un-rotated data. Additionally, we proposed a procedure of signal matching that can substantially increase data quality.
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Jarvis, Kevin D., and Rosemary Knight. "Near‐surface VSP surveys using the seismic cone penetrometer." GEOPHYSICS 65, no. 4 (July 2000): 1048–56. http://dx.doi.org/10.1190/1.1444798.
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We have found that high‐quality vertical seismic profile (VSP) data can be collected for near‐surface applications using the seismic cone penetrometer. Cone‐mounted accelerometers are used as the VSP receivers, and a sledgehammer against the cone truck baseplate is used as a source. This technique eliminates the need to drill a borehole, thereby reducing the cost of the survey, and results in a less invasive means of obtaining VSP data. Two SH-wave VSP surveys were acquired over a deltaic sand/silt sequence and compared to an SH-wave common‐depth‐point (CDP) reflection profile. The VSP data were processed using a combination of singular‐value‐decomposition filtering, deconvolution, and f-k filtering to produce the final VSP extracted traces. The VSP traces correlate well with cone geotechnical logs and the CDP surface‐seismic data. The first breaks from the VSP can be used to generate shear‐wave velocity profiles that are important for time‐to‐depth conversion and the velocity correction of the CDP surface data.
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Pratt, Thomas L., James F. Dolan, Jackson K. Odum, William J. Stephenson, Robert A. Williams, and Mary E. Templeton. "Multiscale seismic imaging of active fault zones for hazard assessment: A case study of the Santa Monica fault zone, Los Angeles, California." GEOPHYSICS 63, no. 2 (March 1998): 479–89. http://dx.doi.org/10.1190/1.1444349.
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High‐resolution seismic reflection profiles at two different scales were acquired across the transpressional Santa Monica Fault of north Los Angeles as part of an integrated hazard assessment of the fault. The seismic data confirm the location of the fault and related shallow faulting seen in a trench to deeper structures known from regional studies. The trench shows a series of near‐vertical strike‐slip faults beneath a topographic scarp inferred to be caused by thrusting on the Santa Monica fault. Analysis of the disruption of soil horizons in the trench indicates multiple earthquakes have occurred on these strike‐slip faults within the past 50 000 years, with the latest being 1000 to 3000 years ago. A 3.8-km-long, high‐resolution seismic reflection profile shows reflector truncations that constrain the shallow portion of the Santa Monica Fault (upper 300 m) to dip northward between 30° and 55°, most likely 30° to 35°, in contrast to the 60° to 70° dip interpreted for the deeper portion of the fault. Prominent, nearly continuous reflectors on the profile are interpreted to be the erosional unconformity between the 1.2 Ma and older Pico Formation and the base of alluvial fan deposits. The unconformity lies at depths of 30–60 m north of the fault and 110–130 m south of the fault, with about 100 m of vertical displacement (180 m of dip‐slip motion on a 30°–35° dipping fault) across the fault since deposition of the upper Pico Formation. The continuity of the uncomformity on the seismic profile constrains the fault to lie in a relatively narrow (50 m) zone, and to project to the surface beneath Ohio Avenue immediately south of the trench. A very high‐resolution seismic profile adjacent to the trench images reflectors in the 15 to 60 m depth range that are arched slightly by folding just north of the fault. A disrupted zone on the profile beneath the south end of the trench is interpreted as being caused by the deeper portions of the trenched strike‐slip faults where they merge with the thrust fault.
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Yu, Siwei, Jianwei Ma, and Bangliu Zhao. "Off-the-grid vertical seismic profile data regularization by a compressive sensing method." GEOPHYSICS 85, no. 2 (February 12, 2020): V157—V168. http://dx.doi.org/10.1190/geo2019-0357.1.
Full textAbstract:
Different from the surface survey, the vertical seismic profile (VSP) survey deploys sources on the surface and geophones in a well. VSP provides higher resolution information of subsurface structures. The faults that cannot be imaged with surface seismic data may be detected with VSP data, and detailed analysis of fracture zones can be achieved with multicomponent VSP. However, one of the main problems is that the sources seldom are acquired on a regular grid in realistic VSP surveys. The irregular samplings cause serious artifacts in migration or imaging, such that data regularization must be implemented first. We have developed a compressive sensing (CS)-based method to regularize nonstationary VSP data. Our method directly operates on irregularly gridded data sets, which is a key contribution compared to the existing CS-based reconstruction methods that work on regular grids. The CS framework consists of a sparsity constraint and a penalty term. We have used the curvelet transform for sparsity constraint of nonstationary events in the regularization term and the nonequispaced Fourier transform to regularize the VSP data in a penalty term. An alternative directional method of multipliers is used for solving the optimization problem. Our method is tested on synthetic, field 2D and 3D VSP data sets. Our method obtains improved reconstructions on continuities of the events and produces fewer artifacts compared to the well-known antileaking Fourier transform method.
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Grech, M. Graziella Kirtland, Don C. Lawton, and Scott Cheadle. "Integrated prestack depth migration of vertical seismic profile and surface seismic data from the Rocky Mountain Foothills of southern Alberta, Canada." GEOPHYSICS 68, no. 6 (November 2003): 1782–91. http://dx.doi.org/10.1190/1.1635031.
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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.