Imperial College London

ProfessorYanghuaWang

Faculty of EngineeringDepartment of Earth Science & Engineering

Principal of Resource Geophysics Academy and Director of CRG
 
 
 
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Contact

 

+44 (0)20 7594 1171yanghua.wang Website

 
 
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Location

 

2.40Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

140 results found

Song C, Wang Y, 2023, Simulating seismic multifrequency wavefields with the Fourier feature physics-informed neural network, GEOPHYSICAL JOURNAL INTERNATIONAL, Vol: 232, Pages: 1503-1514, ISSN: 0956-540X

Journal article

Zhao Z, Rao Y, Wang Y, 2023, Structure-adapted multi-channel matching pursuit for seismic trace decomposition, Pure and Applied Geophysics, ISSN: 0033-4553

Journal article

Hao Y, Bell R, Rao Y, Fan R, Wang Yet al., 2023, Prediction of permian karst reservoirs in the yuanba gas field, northern sichuan basin, China, Marine and Petroleum Geology, Pages: 106160-106160, ISSN: 0264-8172

Journal article

Cai S, Fang F, Wang Y, 2023, Nonstationary seismic-well tying with time-varying wavelets, Geophysics, Vol: 88, ISSN: 0016-8033

Seismic-well tying is an important technique for correlating well-logging curves in depth with seismic traces in time. An appropriate seismic-well tying technique must account for two types of nonstationarity: the nonstationary time errors in the synthetic seismic trace caused by the inaccurate time-depth relationship established based on sonic-logging velocity and the nonstationary seismic signals due to the time-varying wavelets during wave propagation. The nonstationary problems related to the time-depth relationship and the time-varying wavelets are interrelated in seismic-well tying procedure. We implemented a nonstationary seismic-well tying method by iteratively updating the time-depth relationship and estimating the time-varying wavelets. From the estimated time-varying wavelets, we also estimated a Q-value by assuming that the subsurface medium has a constant Q at depth and used the constant Q to constrain the variation of the seismic wavelet during propagation. Then, we used the improved time-depth relationship and time-varying wavelets with the Q constraint for further iterations. In the iterative procedure, we quantified the accuracy of the seismic-well tying result using the correlation coefficient between the synthetic and the true seismic trace in each iteration and evaluated the reliability using the normalized mean-square errors among the wavelets estimated in different iterations.

Journal article

Xu Q, Wang Y, 2023, Determination of the viscoelastic parameters for the generalized viscoelastic wave equation, Geophysical Journal International, Vol: 233, Pages: 875-884, ISSN: 0956-540X

<jats:title>SUMMARY</jats:title> <jats:p>The viscoelasticity of subsurface media is succinctly represented in the generalized wave equation by a fractional time derivative. This generalized viscoelastic wave equation is characterized by the viscoelastic parameter and the viscoelastic velocity, but these parameters are not well formulated and therefore unfavourable for seismic implementation. Here, we prove that the generalized wave equation is causal and stable by deriving the rate-of-relaxation function. Causality and stability are two necessary conditions for the applicability of the wave equation in seismic simulations. On this basis, we determine the physical parameters for the application of the generalized wave equation. First, we formulate the relationship between the viscoelastic parameter and the constant Q model. The proposed frequency-independent relation agrees with the theoretical solution and fits the field data. Then, we formulate the viscoelastic velocity in terms of the reference velocity and the viscoelastic parameter. These two formulations adequately represent the viscoelastic effect in seismic wave propagation and lead to an improvement in the accuracy of the numerical simulation of the generalized viscoelastic wave equation.</jats:p>

Journal article

Yao J, Warner M, Wang Y, 2023, Regularization of anisotropic full-waveform inversion with multiple parameters by adversarial neural networks, Geophysics, Vol: 88, Pages: R95-R103, ISSN: 0016-8033

The anisotropic full-waveform inversion (FWI) is a seismic inverse problem for multiple parameters, which aims to simultaneously reconstruct the vertical velocity and the anisotropic parameters of the earth's subsurface. This multiparameter inverse problem suffers from two issues. First, the objective function of the data fitting is less sensitive to the anisotropic parameters. Second, the crosstalk effect among the different parameters worsens the model update in the iterative inversion. We have developed a method that statistically regularizes the anisotropic FWI using Wasserstein adversarial networks, by penalizing the Wasserstein distance between the distribution of the current model parameters and that of the parameters at the borehole locations. The regularizer can mitigate the issues of anisotropic FWI with multiple parameters and therefore it also can be applied to other inverse problems with multiple parameters.

Journal article

Zhao Z, Rao Y, Wang Y, 2022, The W transform with a chirp-modulated window, GEOPHYSICS, Pages: 1-29, ISSN: 0016-8033

<jats:p> A high-resolution time?frequency spectrum is desirable for processing and interpreting seismic data. The standard W transform is a method that effectively preserves the resolution in the low-frequency region of the time?frequency spectrum of non-stationary seismic signals. To further increase the energy concentration of the time?frequency spectrum estimated with the standard W transform, we propose to combine the W transform with a chirp-modulated window. The chirp rate in the chirp-modulated window can control the rotation of the window in the time?frequency plane to achieve a better match with the time?frequency spectrum. Unlike the general linear chirplet transform, the chirp rate in the proposed algorithm can be directly determined with the estimated instantaneous frequency. It has been shown that the W transform with a chirp-modulated window maintains the resolution of the time?frequency spectrum and improves the energy concentration around the dominant frequency against noise. To speed up the computational process of the W transform with a chirp-modulated window, we formulate the transform as a matrix?vector multiplication, which can be accelerated by using GPU computations. The application of the proposed algorithm to synthetic and field data shows that the frequency anomalies can be easily identified with the proposed algorithm. </jats:p>

Journal article

Wang G, Chen S, Wang Y, 2022, Direct inversion for the equivalent pore aspect ratio based on the theory of ellipsoid modelling, Geophysical Prospecting, ISSN: 0016-8025

Journal article

Zhang H, Brito-Parada PR, Neethling SJ, Wang Yet al., 2022, Yield stress of foam flow in porous media: The effect of bubble trapping, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, Vol: 655, ISSN: 0927-7757

Journal article

Wang Y, 2022, Time–frequency Analysis of Seismic Signals, Publisher: Wiley, ISBN: 9781119892342

Time–frequency analysis of seismic signals aims to reveal the local properties of nonstationary signals. The local properties such as time-period, frequency, and spectral content are varying with time, and the time of a seismic signal is a proxy of geologic depth. Therefore, the time–frequency spectrum is composed of the frequency spectra that are generated by using the classic Fourier transform at different time positions. Different time–frequency analysis methods are distinguished in the construction of the local kernel prior to using the Fourier transform. Based on the difference in constructing the Fourier transform kernel, this book divides time–frequency analysis methods into two groups, the Gabor transform-type methods and the energy density distribution methods. This book provides a practical guide to geophysicists who attempt to generate geophysically meaningful time–frequency spectra, who attempt to process seismic data with time-dependent operations for the fidelity of nonstationary ...

Book

Wang Y, 2022, Time-frequency domain local spectral analysis of seismic signals with multiple windows, PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 478, ISSN: 1364-5021

Journal article

Yu Y, Cilliers J, Hadler K, Starr S, Wang Yet al., 2022, A review of particle transport and separation by electrostatic traveling wave methods, Journal of Electrostatics, Vol: 119, Pages: 1-16, ISSN: 0304-3886

The controlled movement of dry particles using non-mechanical means is desirable in a number of different applications, including solar panel dust mitigation, toner particle motion and in the handling and beneficiation of regolith for In-Situ Resource Utilization (ISRU). The electric curtain, the electrostatic traveling wave (ETW) and the electro-dynamic screen (EDS) are examples of techniques that can transport and separate particles with no moving parts nor fluid medium. This review paper brings together the research carried out on these techniques.We provide a comprehensive review on the particle movement mechanisms and the development and application of ETW methods, featuring a diverse range of hardware and circuitry, particulate material and process objectives. We focus on the evaluation of experimental development in the area of dust mitigation, particle transport and ISRU processes. We also detail the current knowledge about theory and modelling methods. Moreover, we provide a guide for possible improvement of the effectiveness of ETW devices, by outlining the limitations in application, theoretical understanding and potential research aspects.

Journal article

Guo X, Shi Y, Wang W, Ke X, Wang Yet al., 2022, Suppressing migration noise in reverse time migration of vertical seismic profiles by multiple stacking estimation, GEOPHYSICS, Vol: 87, Pages: S223-S235, ISSN: 0016-8033

Journal article

XU QIANG, WANG YANGHUA, 2022, Spatial Filter for the Pseudo-spectral Implementation of Fractional Derivative Wave Equation, PURE AND APPLIED GEOPHYSICS, Vol: 179, Pages: 2831-2840, ISSN: 0033-4553

Journal article

Yao J, Warner M, Wang Y, 2022, Generating surface-offset common-image gathers with backward wavefield synthesis, GEOPHYSICS, Vol: 87, Pages: S129-S135, ISSN: 0016-8033

Journal article

Song C, Wang Y, 2022, High-frequency wavefield extrapolation using the Fourier neural operator, JOURNAL OF GEOPHYSICS AND ENGINEERING, Vol: 19, Pages: 269-282, ISSN: 1742-2132

Journal article

Yao J, Wang Y, 2022, Building a full-waveform inversion starting model from wells with dynamic time warping and convolutional neural networks, GEOPHYSICS, Vol: 87, Pages: R223-R230, ISSN: 0016-8033

Journal article

Ni J, Gu H, Wang Y, 2022, Seismic wave equation formulated by generalized viscoelasticity in fluid-saturated porous media, GEOPHYSICS, Vol: 87, Pages: T111-T121, ISSN: 0016-8033

Journal article

OMalley CPB, Roberts GG, Mannion PD, Hackel J, Wang Yet al., 2022, Coherence of Terrestrial Vertebrate Species Richness with External Drivers Across Scales and Taxonomic Groups, Publisher: Cold Spring Harbor Laboratory

<jats:title>Abstract</jats:title><jats:sec><jats:title>Aim</jats:title><jats:p>Understanding connections between environment and biodiversity is crucial for conservation, identifying causes of ecosystem stress, and predicting population responses to changing environments. Explaining biodiversity requires an understanding of how species richness and environment co-vary across scales. Here, we identify scales and locations at which biodiversity is generated and correlates with environment.</jats:p></jats:sec><jats:sec><jats:title>Location</jats:title><jats:p>Full latitudinal range per continent.</jats:p></jats:sec><jats:sec><jats:title>Time period</jats:title><jats:p>Present-day.</jats:p></jats:sec><jats:sec><jats:title>Major taxa studied</jats:title><jats:p>Terrestrial vertebrates: all mammals, carnivorans, bats, songbirds, humming-birds, amphibians.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>We describe the use of wavelet power spectra, cross-power and coherence for identifying scale-dependent trends across Earth’s surface. Spectra reveal scale- and location-dependent coherence between species richness and topography (<jats:italic>E</jats:italic>), mean annual precipitation (<jats:italic>Pn</jats:italic>), temperature (<jats:italic>Tm</jats:italic>) and annual temperature range (∆<jats:italic>T</jats:italic>).</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p><jats:italic>&gt;</jats:italic>97% of species richness of taxa studied is generated at large scales, i.e. wavelengths 10<jats:sup>3</jats:sup>km, with 30–69% generated at scales 10<jats:sup>4</jats:sup>km. At these scales, richness tends to be highly cohere

Working paper

Alsalmi H, Wang Y, 2021, Mask filtering to the Wigner-Ville distribution, GEOPHYSICS, Vol: 86, Pages: V489-V496, ISSN: 0016-8033

Journal article

Jamali J, Javaherian A, Wang Y, Ameri MJet al., 2021, The behavior of elastic moduli with fluid content in the VTI media, JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING, Vol: 208, ISSN: 0920-4105

Journal article

Wu D, Wang Y, Cao J, da Silva N, Yao Get al., 2021, Least-squares reverse-time migration with sparsity constraints, JOURNAL OF GEOPHYSICS AND ENGINEERING, Vol: 18, Pages: 304-316, ISSN: 1742-2132

Journal article

Izadian S, Aghazade K, Amini N, Wang Yet al., 2021, Semi-exact local absorbing boundary condition for seismic wave simulation, JOURNAL OF GEOPHYSICS AND ENGINEERING, Vol: 18, Pages: 62-73, ISSN: 1742-2132

Journal article

Wang Y, 2021, The W transform, GEOPHYSICS, Vol: 86, Pages: V31-V39, ISSN: 0016-8033

Journal article

Rosa DR, Santos JMC, Souza RM, Grana D, Schiozer DJ, Davolio A, Wang Yet al., 2020, Comparing different approaches of time-lapse seismic inversion, JOURNAL OF GEOPHYSICS AND ENGINEERING, Vol: 17, Pages: 929-939, ISSN: 1742-2132

Journal article

Duarte EF, da Costa CAN, de Araujo JM, Wang Y, Rao Yet al., 2020, Seismic shot-encoding schemes for waveform inversion, JOURNAL OF GEOPHYSICS AND ENGINEERING, Vol: 17, Pages: 906-913, ISSN: 1742-2132

Journal article

Wang Y, Liu X, Gao F, Rao Yet al., 2020, Robust vector median filtering with a structure-adaptive implementation, GEOPHYSICS, Vol: 85, Pages: V407-V414, ISSN: 0016-8033

Journal article

Li H, Gao R, Wang Y, 2020, Predicting the thickness of sand strata in a sand-shale interbed reservoir based on seismic facies analysis, JOURNAL OF GEOPHYSICS AND ENGINEERING, Vol: 17, Pages: 592-601, ISSN: 1742-2132

Journal article

Wang R, Wang Y, Rao Y, 2020, Seismic reflectivity inversion using an L1-norm basis-pursuit method and GPU parallelisation, JOURNAL OF GEOPHYSICS AND ENGINEERING, Vol: 17, Pages: 776-782, ISSN: 1742-2132

Journal article

Wang Y, Rao Y, 2020, Seismic, Waveform Modeling and Tomography, Encyclopedia of Solid Earth Geophysics, 2nd edition, Editors: Gupta, Publisher: Springer, Cham, ISBN: 978-3-030-10475-7

Tomography. A seismic inversion method to produce slicing image of the internal structures of an object, by recording seismic wavefield propagating through and scattered-refracted-reflected back from the object and observing the difference in the effects on the wave energy impinging on those structures.

Book chapter

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