Waveform inverstion of marine reflection seismograms for P impedance and Poisson's ratio

Igel, Heiner; Djikpesse, Hugues; Tarantola, Albert

doi:10.1111/j.1365-246x.1996.tb07026.x

Cited by 92 publications

(72 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Changes in lithology, pore pressure and saturating fluids produce differential variations of compressibility and shear properties, determining changes on the ratio between P-wave and S-wave velocities (Vp/Vs) (Ruthenford & Williams, 1989;Mallick & Dutta, 2002;Igel et al, 1996). How-ever, the Vp/Vs ratio controls the reflectivity of a medium via the Poisson's ratio (Koefoed, 1955;Mavko et al, 2009):…”

Section: Sensitivity To Poisson's Ratio In High Vp/vs Mediamentioning

confidence: 99%

“…In marine reflection seismic data, the presence of only one propagation mode impedes the opportunity to obtain independent estimates of P-wave (Vp) and S-wave velocity (Vs) (Jin et al, 1992;Igel et al, 1996); on the other hand, density is strongly coupled with P-wave velocity at narrow reflection angle; the two parameters can't be effectively resolved and in fact yield a posterior reconstruction of the P-impedance model (Tarantola, 1986;Operto et al, 2013). Here we choose to parametrise the reflectivity of the earth model as a distribution of P-impedance, Poisson's ratio and density (Debski & Tarantola, 1995;Igel et al, 1996), super-imposed to a long-wavelength P-wave velocity model that controls the wavefield kinematic (Tarantola, 1986;Jannane, 1989).…”

Section: A Strategy For the Multi-parameter Problemmentioning

confidence: 99%

“…Debski & Tarantola, 1995;Jannane, 1989;Igel et al, 1996). We conduct a sensitivity analysis on a simple homogeneous model with a low impedance 50 cm thick layer, whose density is changed at constant impedance, as a function of the maximum reflection angle at the target.…”

Section: Sensitivity To Constant-impedance Density Variationsmentioning

confidence: 99%

“…The resulting Hessian matrix for a scatterer layer is highly rank-deficient, meaning that only one parameter class can be effectively inverted for in a simultaneous multiparameter inversion ; despite the inherent stability of the SVD approach, this makes the multiplication by the inverse Hessian not ideal as a means to uncouple the different components of the gradient. On the other hand, the angle dependancy of the secondary virtual sources for the chosen parametrisation, allows us to orthogonalise the problem by appropriately weighting the residual wavefield and inverting sequentially each independent parameter, from the strongest to the weakest contributor to the residual energy (Tarantola, 1986;Igel et al, 1996;Operto et al, 2013). This approach has also the advantage of a simpler implementation of the regularised least-square inversion, as it does not require to build a model covariance matrix that balances the contribution of parameters with different weights (Eq.…”

Section: A Strategy For the Multi-parameter Problemmentioning

confidence: 99%

“…Although such properties can be retrieved through the inversion of the reflections' AVO, a full waveform approach has the advantage to account for all the wave phenomena (Tarantola, 1984(Tarantola, , 1986Fichtner, 2011), within the required resolution and modelling approximation. By exploiting the information contained in the complete waveform, FWI outperforms AVO inversion in most realistic reservoir geophysics application (Mallick & Adhikari, 2015), especially when complicated layer interference and velocity gradients are present (Xu et al, 1993;Igel et al, 1996), which is likely to be a factor in UHF near-surface seismic data.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Pre-stack full waveform inversion of ultra-high-frequency marine seismic reflection data

Provenzano

Vardy

Henstock

2017

Geophysical Journal International

View full text Add to dashboard Cite

SUMMARYThe full waveform inversion (FWI) of seismic reflection data aims to reconstruct a detailed physical properties model of the subsurface, fitting both the amplitude and traveltime of the reflections generated at physical discontinuities in the propagation medium. Unlike reservoirscale seismic exploration, where seismic inversion is a widely adopted remote characterisation tool, ultra high frequency (UHF, 0.2-4.0 kHz) multi-channel marine reflection seismology is still most often limited to a qualitative interpretation of the reflections' architecture. Here we propose an elastic full waveform inversion methodology, custom-tailored for pre-stack UHF marine data in vertically heterogeneous media to obtain a decimetric-scale distribution of Pimpedance, density and Poisson's ratio within the shallow sub-seabed sediments. We address the deterministic multi-parameter inversion in a sequential fashion. The complex trace instantaneous phase is first inverted for the P-wave velocity to make-up for the lack of low-frequency in the data and reduce the non-linearity of the problem. This is followed by a short-offset Pimpedance optimisation and a further step of full offset range Poisson's ratio inversion. Provided that the seismogram contains wide reflection angles (> 40 degrees), we show that it is possible to invert for density and decompose a-posteriori the relative contribution of P-wave velocity and density to the P-impedance. A broad range of synthetic tests is used to prove the potential of the methodology and highlights sensitivity issues specific to UHF seismic. An example application to real data is also presented. In the real case, trace normalisation is applied to minimise the systematic error deriving from an inaccurate source wavelet estimation. G. Provenzano et al.The inverted model for the top 15 meters of the sub-seabed agrees with the local lithological information and core-log data. Thus we can obtain a detailed remote characterisation of the shallow sediments using a multi-channel sub-bottom profiler within a reasonable computing cost and with minimal pre-processing. This has the potential to reduce the need of extensive geotechnical coring campaigns.

show abstract

Section: Sensitivity To Poisson's Ratio In High Vp/vs Mediamentioning

confidence: 99%

Section: A Strategy For the Multi-parameter Problemmentioning

confidence: 99%

Section: Sensitivity To Constant-impedance Density Variationsmentioning

confidence: 99%

Section: A Strategy For the Multi-parameter Problemmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Pre-stack full waveform inversion of ultra-high-frequency marine seismic reflection data

Provenzano

Vardy

Henstock

2017

Geophysical Journal International

View full text Add to dashboard Cite

show abstract

Resolution analysis by random probing

Fichtner

Leeuwen

2015

JGR Solid Earth

View full text Add to dashboard Cite

We develop and apply methods for resolution analysis in tomography, based on stochastic probing of the Hessian or resolution operators. Key properties of our methods are (i) low algorithmic complexity and easy implementation, (ii) applicability to any tomographic technique, including full‐waveform inversion and linearized ray tomography, (iii) applicability in any spatial dimension and to inversions with a large number of model parameters, (iv) low computational costs that are mostly a fraction of those required for synthetic recovery tests, and (v) the ability to quantify both spatial resolution and interparameter trade‐offs. Using synthetic full‐waveform inversions as benchmarks, we demonstrate that autocorrelations of random‐model applications to the Hessian yield various resolution measures, including direction‐ and position‐dependent resolution lengths and the strength of interparameter mappings. We observe that the required number of random test models is around five in one, two, and three dimensions. This means that the proposed resolution analyses are not only more meaningful than recovery tests but also computationally less expensive. We demonstrate the applicability of our method in a 3‐D real‐data full‐waveform inversion for the western Mediterranean. In addition to tomographic problems, resolution analysis by random probing may be used in other inverse methods that constrain continuously distributed properties, including electromagnetic and potential‐field inversions, as well as recently emerging geodynamic data assimilation.

show abstract

Full‐waveform inversion of the Japanese Islands region

et al. 2016

View full text Add to dashboard Cite

We present a full‐waveform tomographic model of the crust and upper mantle beneath the Japanese Islands region. This is based on the combination of GPU‐accelerated spectral‐element wavefield simulations, adjoint techniques, and nonlinear optimization. Our model explains complete seismic waveforms of events not used in the inversion in the period range from 20 to 80 s. Quantitative resolution analysis indicates that resolution lengths within the well‐covered areas are around 150 km in the horizontal and around 30 km in the vertical directions. In addition to the high‐velocity signatures of known lithospheric slabs in the region, our model reveals a pronounced low‐velocity anomaly beneath the volcanic island of Ulleung in the Sea of Japan, reaching −19% around 100 km depth. The Ulleung anomaly originates at or above the Pacific slab, rises vertically upward to the base of the Philippine Sea slab at ∼200 km depth, circumvents it in NW direction, and then significantly strengthens in the uppermost mantle above the Philippine Sea slab. Among the numerous hypotheses for the generation of low‐velocity anomalies in subduction systems, those invoking instabilities before or when a slab enters the transition zone seem most likely. The age and fast subduction of the Pacific slab may facilitate the transport of fluids into the transition zone. This may promote the reduction in viscosity and the onset of convective upwelling, aided by ambient mantle flow, such as return flow within the mantle wedge.

show abstract

Waveform inverstion of marine reflection seismograms for P impedance and Poisson's ratio

Cited by 92 publications

References 21 publications

Pre-stack full waveform inversion of ultra-high-frequency marine seismic reflection data

Pre-stack full waveform inversion of ultra-high-frequency marine seismic reflection data

Resolution analysis by random probing

Full‐waveform inversion of the Japanese Islands region

Contact Info

Product

Resources

About