About probabilistic integration of ill-posed geophysical tomography and logging data: A knowledge discovery approach versus petrophysical transfer function concepts illustrated using cross-borehole radar-, P- and S-wave traveltime tomography in combination with cone penetration and dielectric logging data

The seismic cone penetration test (SCPT) has proven to be a very valuable geotechnical tool in facilitating the determination of low strain (<104%) in situ compression (P) and shear (S) wave velocities. The P- and S-wave velocities are directly related to the soil elastic constants of Poisson's ratio, shear modulus, bulk modulus, and Young's modulus. The accurate determination of P- and S-wave velocities from the recorded seismic cone time series is of paramount importance to the evaluation of reliable elastic constants. Furthermore, since the shear and compression wave velocities are squared in deriving the elastic constants, small variations in the estimated velocities can cause appreciable errors. The standard techniques implemented in deriving SCPT interval velocities rely upon obtaining reference P- and S-wave arrival times as the probe is advanced into the soil profile. By assuming a straight ray travel path from the source to the SCPT seismic receiver and calculating the relative reference arrival time differences, interval SCPT velocities are obtained. The forward modeling downhill simplex method (FMDSM) outlined in this paper offers distinct advantages over conventional SCPT velocity profile estimation methods. Some of these advantages consist of the allowance of ray path refraction, greater sophistication in interval velocity determination, incorporation of measurement weights, and meaningful interval velocity accuracy estimators.Key words: seismic cone penetration testing (SCPT), downhill simplex method (DSM), forward modeling, Fermat's principle, weighted least squares (l2 norm), cost function.

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Integrating S‐wave seismic‐reflection data and cone penetration test data using a multiangle multiscale approach

Geophysics ◽

10.1190/1.1707064 ◽

2004 ◽

Vol 69 (2) ◽

pp. 440-459 ◽

Cited By ~ 32

Author(s):

Ranajit Ghose ◽

Jeroen Goudswaard

Keyword(s):

Wave Velocity ◽

Seismic Reflection ◽

Multiscale Analysis ◽

S Wave ◽

Cone Penetration ◽

Seismic Reflection Data ◽

Cone Resistance ◽

Reflection Seismic ◽

Reflection Data

A cone penetration test (CPT) is the most common geotechnical testing method used to estimate in situ the strength properties of soil. Although CPT provides valuable information, this information is restricted to the location of the measurement. We propose a new concept to integrate shallow S‐wave reflection seismic data with CPT data in order to obtain laterally continuous subsoil information. In this vein, a valid quantitative means to relate seismic reflections to CPT data is a primary requirement. The approach proposed here is based on the characterization of the scaling behavior of the local fine‐scale S‐wave velocity information extracted from the seismic reflection data and the same behavior of the CPT cone resistance. The local velocity contrast information is extracted by linearized Zoeppritz inversion of the amplitude‐preserved prestack reflection data. We have formulated a multiscale analysis approach employing the continuous wavelet transform in order to quantitatively characterize the nature of change at an interface of the local S‐wave velocity contrast and the CPT cone resistance and to illuminate any relation between these two. The multiscale analysis estimates the singularity parameter α, which indicates the nature of the interfacial change. The application of our method to the field data has uncovered a striking relation between the nature of variation of the local S‐wave velocity contrast and that of CPT cone resistance; otherwise, such a relation was not visible. Detailed analyses of two extensive field datasets have shown that the lateral fine‐scale variation of soil strength, as seen by CPT cone resistance, has a close resemblance with the variation of the local S‐wave velocity function as seen by angle‐dependent reflection measurements. This leads to a unique possibility to integrate two very different in‐situ measurements—reflection seismic and CPT—providing laterally continuous detailed information of the soil layer boundaries.

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The influence of S-wave velocity of subsurface layer on transfer function of model ground.

Doboku Gakkai Ronbunshu ◽

10.2208/jscej.1986.368_329 ◽

1986 ◽

pp. 329-336

Author(s):

Tsutomu SAWADA ◽

Kiyoshi HIRAO

Keyword(s):

Transfer Function ◽

Wave Velocity ◽

Subsurface Layer ◽

S Wave

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A comparison of phase inversion and traveltime tomography for processing near-surface refraction traveltimes

Geophysics ◽

10.1190/1.3196857 ◽

2009 ◽

Vol 74 (6) ◽

pp. WCB11-WCB24 ◽

Cited By ~ 20

Author(s):

Karl J. Ellefsen

Keyword(s):

Standard Deviation ◽

Phase Inversion ◽

Small Scale ◽

Complex Frequency ◽

S Wave ◽

Near Surface ◽

Residual Standard Deviation ◽

Wave Refraction ◽

Traveltime Tomography ◽

The Difference

With phase inversion, one can estimate subsurface velocities using the phases of first-arriving waves, which are the frequency-domain equivalents of the traveltimes. Phase inversion is modified to make it suitable for processing traveltimes from near-surface refraction surveys. The modifications include parameterizing the model, correcting the observed phases, and selecting the complex frequency. This modified phase inversion is compared to traveltime tomography. For two comparisons using computer-simulated traveltimes, the difference between the estimated and correct models, the residual mean, and the residual standard deviation are smaller for the phase inversion than they are for the traveltime tomography. For a comparison using field data from an S-wave refraction survey, both methods estimate models that are consistent with the known geology. Nonetheless, the phase-inversion model includes small-scale features in the bedrock that are geologically plausible; the residual mean and the residual standard deviation are smaller for the phase inversion than they are for the traveltime tomography.

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Inversion of the reflected SV-wave for density and S-wave velocity structures

Geophysical Journal International ◽

10.1093/gji/ggaa096 ◽

2020 ◽

Vol 221 (3) ◽

pp. 1635-1639

Author(s):

Feng Zhang ◽

Xiang-yang Li

Keyword(s):

Wave Velocity ◽

Incident Angle ◽

Seismic Exploration ◽

S Wave ◽

Geological Interpretation ◽

Data Application ◽

Essential Properties ◽

Global Seismology ◽

Ill Posed ◽

Formation And Evolution

SUMMARY Density is one of the most essential properties that determines the dynamic behavior of the Earth. Besides, density has been commonly used to investigate the mineral composition, porosity and fluid content of rock. Therefore, a reliable estimation of the density structure is one of the most important objectives in both global seismology and seismic exploration. However, seismic inversions of independent density estimates are ill-posed because density has a large trade-off with velocities. Shear wave propagation is sensitive to both density and the S-wave velocity. We show that the reflected SV-wave (SV-to-SV wave) at an incident angle of 22.5o depends only on density contrast, and at incident angle 30o it depends only on S-wave velocity contrast. Thus, density as well as S-wave velocity can be directly inverted from the reflected SV-wave as separate and independent parameters. The forward modelling has high accuracy, the inverse problem is well-posed and the misfit function can be easily regularized. Field data application demonstrates the proposed method can efficiently recover reliable and high-resolution density and S-wave velocity of fine sturctures. Thus, this method has great potential in geological interpretation including understanding regional Moho structure, crustal and mantle formation and evolution, and rock lithologic composition and fluid-filled porosity.

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High‐resolution crosswell imaging of a west Texas carbonate reservoir: Part 5—Core analysis

Geophysics ◽

10.1190/1.1443810 ◽

1995 ◽

Vol 60 (3) ◽

pp. 712-726 ◽

Cited By ~ 13

Author(s):

Richard C. Nolen‐Hoeksema ◽

Zhijing Wang ◽

Jerry M. Harris ◽

Robert T. Langan

Keyword(s):

Wave Velocity ◽

Field Experiments ◽

Velocity Ratio ◽

Carbonate Reservoir ◽

P Wave ◽

Core Analysis ◽

S Wave ◽

Traveltime Tomography ◽

West Texas ◽

P Wave Velocity

We conducted a core analysis program to provide supporting data to a series of crosswell field experiments being carried out in McElroy Field by Stanford University’s Seismic Tomography Project. The objective of these experiments is to demonstrate the use of crosswell seismic profiling for reservoir characterization and for monitoring [Formula: see text] flooding. For these west Texas carbonates, we estimate that [Formula: see text] saturation causes P‐wave velocity to change by −1.9% (pooled average, range = −6.3 to +0.1%), S‐wave velocity by +0.6% (range = 0 to 2.7%), and the P‐to‐S velocity ratio by −2.4% (range = −6.4 to −0.3%). When we compare these results to the precisions we can expect from traveltime tomography (about ±1% for P‐ and S‐wave velocity and about ±2% for the P‐to‐S velocity ratio), we conclude that time‐lapse traveltime tomography is sensitive enough to resolve changes in the P‐wave velocity, S‐wave velocity, and P‐to‐S velocity ratio that result from [Formula: see text] saturation. We concentrated here on the potential for [Formula: see text] saturation to affect seismic velocities. The potential for [Formula: see text] saturation to affect other seismic properties, not discussed here, may prove to be more significant (e.g., P‐wave and S‐wave impedance).

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