Sjoerd Antonius Leonardus de Ridder

• PhD
• Lecturer at University of Leeds

Magnetic sounding using data collected from the Juno mission can be used to provide constraints on Jupiter’s interior. However, inwards continuation of reconstructions assuming zero electrical conductivity and a representation in spherical harmonics are limited by the enhancement of noise at small scales. Here we describe new time-independent recon...

As is known, neural networks can universally approximate any complex functions. This ground truth naturally makes it a suitable candidate for solution representation of complex partial differential equation (PDE) governed. For planetary magnetic field modelling problem, spherical harmonic functions are most used as standard modelling method. Spheri...

Surface waves are a particular type of seismic wave that propagate around the surface of the Earth, but which oscillate over depth ranges beneath the surface that depend on their frequency of oscillation. This causes them to travel with a speed that depends on their frequency, a property called dispersion. Estimating surface wave dispersion is of i...

The propagator matrix "propagates" a full wave field from one depth level to another, accounting for large propagation angles and evanescent waves. The Marchenko focusing function forms the nucleus of data-driven Marchenko redatuming and imaging schemes, accounting for internal multiples. These seemingly different concepts appear to be closely rela...

Marchenko methods are based on integral representations which express Green’s functions for virtual sources and/or receivers in the subsurface in terms of the reflection response at the surface. An underlying assumption is that inside the medium the wave field can be decomposed into downgoing and upgoing waves and that evanescent waves can be negle...

Marchenko methods are based on integral representations which express Green's functions for virtual sources and/or receivers in the subsurface in terms of the reflection response at the surface. An underlying assumption is that inside the medium the wave field can be decomposed into downgoing and upgoing waves and that evanescent waves can be negle...

With the advent of large and dense seismic arrays, novel cheap and fast imaging and inversion methods are needed to exploit the information captured by stations in close proximity to each other and produce results in near real-time. The main objective of this study is to propose a sequence of fast seismic acquisition for dispersion curve extraction...

Full-Waveform Inversion (FWI) uses the information of the full wavefield to deliver high resolution images of the subsurface. Conventional time-lapse FWI uses primarily the transmitted component (diving waves) of the wavefield to reconstruct the low wavenumber component of the velocity model. This requires large offset surveys and low frequency dat...

Seismic surfacewave tomography is a tried and tested method to reveal the subsurface structure of the Earth.However, the conventional 2-step scheme of inverting first for 2-Dmaps of surface wave phase or group velocity and then inverting for the 3-D spatial velocity structure preserves little information about lateral spatial correlations, and intr...

We formulate a full wavefield inversion (FWFI) for ambient seismic noise recorded by large and dense seismograph arrays. FWFI exploits the constraints on the gradients of the wavefield that array data inherently possess. We pose FWFI as a partial differential equation (PDE) constrained inverse problem resulting in a joint estimation of a reconstruc...

Quality factor (Q) or equivalently attenuation α=1/Q describes the amount of energy lost per cycle as a wave travels through a medium. This is important to correct seismic data amplitudes for near-surface effects, to locate subsurface voids or porosity, to aid seismic interpretation, or for characterizing other rock and fluid properties. Seismic at...

Time lapse seismic methods have been extensively used over the past two decades to monitor oil reservoirs under production. Time-lapse changes can result from amplitude changes and/or time shifts. Amplitude changes can be caused by new structures in the target area or reflectivity differences at interfaces. Time shifts are usually the result of phy...

We formulate a full wave field inversion for ambient seismic noise recorded by large and dense seismograph arrays. Full wave field inversion exploits the constraints on the gradients of the wave field that array data inherently possess (the sum is greater than its parts). Consequently, we can relax the spatial and temporal constraints on the wave f...

S U M M A R Y We introduce a wavefield gradiometry technique to estimate both isotropic and anisotropic local medium characteristics from short recordings of seismic signals by inverting a wave equation. The method exploits the information in the spatial gradients of a seismic wavefield that are calculated using dense deployments of seismic arrays....

The author names for the following two summaries originally appeared as Pascal and Yuan and Pascal and Halliday , but they should have read: Edme and Yuan formulate a novel acquisition and processing technique to derive surface-wave dispersion curves from seismic ambient noise. The authors show

We introduce an anisotropic wavefield gradiometry technique to estimate phase velocities from seismic surface wave noise. The method inverts a two-dimensional wave equation, equating the spatial and temporal derivatives of the wavefield amplitudes with elliptically anisotropic medium parameters. The derivatives are evaluated using finite difference...

Recently, a novel method to redatum the wavefield in the sub-surface from a reflection response measured at the surface has gained interest for imaging primaries in the presence of strong internal multiples. A prerequisite for the algorithm is an accurate and correct estimate of the direct-wave Green's function. However, usually we use an estimate...

Many efforts of geophysical processing have traditionally been devoted to the separation, attenuation, and elimination of noise from seismic acquisition data. However, one geophysicist’s noise is another geophysicist’s signal. [Aki (1957)][1] formulated the spatial autocorrelation method, which

Using a dense seismic array in Long Beach, California, we have investigated the effectiveness of using traffic noise for passive subsurface imaging. Spectral analysis revealed that traffic-induced vibrations dominate the ambient seismic noise field at frequencies between 3 and 15 Hz. Using the ambientnoise crosscorrelation technique at these freque...

We have studied an approximately 40-hr recording from the Life of Field Seismic array installed over Ekofisk field to assess whether the recorded ambient seismic energy was suitable for passive seismic surface-wave interferometry. Passive seismic interferometry aims to retrieve virtual seismic sources by crosscorrelation. We have found that the noi...

We propose a new approach for imaging the subsurface using a stochastic wavefield of interface waves present in the ambient seismic field. Unlike seismic interferometry, our technique does not rely on cross correlations to obtain the Green's function between two seismic receivers. Rather, it relies on the local measurements of phase velocity obtain...

We formulated an anisotropic eikonal tomography approach for phase velocities based on a two-dimensional elliptical-anisotropic wave equation. We can fit the parameters of the ellipse directly from measured first-order traveltime-surface gradients and constrain these parameters to vary smoothly over space. The method is applied to Scholte-waves in...

Multicomponent acquisition systems today record incom- plete data because they do not measure rotations. Geophones or accelerometers provide linear motion and hydrophones provide pressure, but no current commercial acquisition system includes sensors that measure rotations. Without rotations, the data pro- vide incomplete recording of the wavefield...

Multi-component acquisition systems today record incomplete data because they do not measure rotations. Geophones or accelerometers provide the linear motion, hydrophones provide the pressure, but no current commercial acquisition system includes sensors that measure rotations. Without rotations, the data provide incomplete recording of the wave fi...

One approach to describe the properties of a complex earth system is to use stochastic methods to characterize statistical variability of seismic velocity (Mai and Beroza (2002)). A stochastic modeling approach requires input in the distributions of the model parameters of interest. A spatial field of distributions for each model point describes th...

We show that a reliable and statistically significant group-velocity time-lapse difference between 2004 and 2010 can be retrieved from ambient-seismic noise in an offshore hydrocarbon exploitation setting. We performed a direct comparison of Scholte-wave group-velocity images obtained using regularized tomography. We characterize the expected varia...

We derived an anisotropic eikonal tomography method for phase velocities based on a two-dimensional elliptical-anisotropic wave equation. The method is applied to Scholte-waves emitted between 0.2 and 1.3 Hz by virtual seismic sourced from stations in the Life of Field Seismic (LoFS) Ocean Bottom Cable (OBC) array installed over Ekofisk field. The...

In this thesis I present an extensive study of the potential to use microseism noise for reservoir-scale passive seismic interferometry. Microseism noise is excited by interfer- ing ocean swells exerting pressure variations on the sea floor. In marine recordings, this noise is composed primarily of interface waves travelling along the sea floor. Pr...

Seismic arrays permanently installed over an oil-field can record data continuously even in the absence of active seismic shooting. We create Love and Scholte wave virtual seismic sources by seismic interferometry, for four datasets recorded between 2004 and 2010. To use an array for 4D monitoring, we must be able to separate 4D effects due to real...

[1] Seismic interferometry is applied to continuous seismic recordings spanning 5 days and over 2200 stations at the Valhall Life-of-Field Seismic array in the Norwegian North Sea. We retrieve both fundamental-mode and first-overtone Scholte waves by cross correlation. Ambient seismic noise tomography using the vertical component of this dense arra...

The Valhall Life of Field Seismic (LoFS) OBC seismic array was installed in 2003 for the purpose of regular long-term 4D monitoring of the Valhall oil field. With academic collaborators, BP has investigated whether it could be used to synthesize virtual sources using passive seismic interferometry, allowing continuous monitoring of the field. The a...

Seismic arrays permanently installed over a hydrocarbon reservoir can record data continuously, even in the absence of active seismic shooting. Here we use a 5 day long recording of ambient seismic noise over a producing oil reservoir to study ambient-seismic noise tomography as a tool for continuous monitoring by passive seismic interferometry. Th...

In January 2012, a 3D seismic array was deployed in Long Beach, California by Signal Hill Petroleum, Inc. The array consists of about 2400 vertical-component geophones, with an average station spacing of 330 m. Data are being continuously recorded (24 hours/day) over a span of four months, making the resulting data ideal for earthquake research and...

We experimentally validate a relatively recent electrokinetic formulation of the streaming potential (SP) coefficient as developed by Pride (1994). The start of our investigation focuses on the streaming potential coefficient, which gives rise to the coupling of mechanical and electromagnetic fields. It is found that the theoretical amplitude value...

Long term effective operation of CCS projects, require low-cost monitoring tools for early detection of potential leaks and drilling hazards. Correlation of passive seismic noise can provide a monitoring tool and an alternative to regular expensive active seismic acquisition. In a marine environment microseism energy is available at frequencies as...

Electrokinetic Fields and Waves: Theory, Experiments and Numerical Modeling

Permanent ocean-bottom cables installed at the Valhall field can repeatedly record high quality active seismic surveys. But in the absence of active seismic shooting, passive data can be recorded and streamed to the platform in real time. Here I studied 29 hours of data using seismic interferometry. I generate omni-directional Scholte-wave virtual-...

Although permanent ocean-bottom cables installed at the Valhall field record high-quality and repeatable active seismic surveys, even in absence of active seismic shooting the array can record an abundance of seismic energy. Seismic interferometry of 29 hours of passive seismic data generates omnidirectional Scholte-wave virtual-sources at very low...

The permanent ocean-bottom array at the Valhall Field in Norway provides an excellent source of passive seismic data to test what might be accomplished with seismic interferometry. The array was installed in 2003 (Kommedal et al., 2004) and data can be recorded for long periods in all weather conditions. The subsurface structure is well known, both...

Seismic interferometry aims to retrieve the Green's function between two receiver stations by correlating measurements of seismic responses at both stations, effectively turning one station into a virtual source. Passive seismic interferometry has mainly focused on retrieving highfrequency (> 10) Hz virtual sources where acquiring data with real so...

We conducted a near surface seismic test at a coal fire in the Southern Ute Nation near Durango, Colorado. The goal was to characterize and image the unburned coal and adjacent burned zone in order to determine the feasibility of any future seismic surveys. The field survey was preceded by a numerical study to optimize the survey design for the fie...

I investigate a scheme of iterated correlations by testing on the recorded coda of the non-proliferation experiment of 1993. This dataset records the primary arrivals and more than 3 minute coda. Correlations of the data, including the primary arrivals, are neither in the field of noise-correlations or in the field of coda-correlations. Although th...

We study a novel approach to seismic interferometry; iterative interferometry. To utilize secondary Huygens sources that illuminate the medium from regions where primary sources are absent, we correlate the coda of correlations. We identify the leading terms in the second round of correlations and study their kinematics using correlation gathers. W...

Interferometric Green's function representations can be used to retrieve a Green's function between two receiver stations, effectively turning one receiver into a source. Through reciprocity theorems of the convolution and correlation types, we derive interferometric Green's function representations for coupled electromagnetic and seismic wave prop...

A seismic recording of the non-proliferation experiment (NPE), made by a petroleum-exploration company in Railroad Valley (Nevada), contains the first break of the regional P phases followed by a three minute long coda. The transverse orientation and sign-bit recording of the array, renders distinguishing phase arrival times difficult. This motivat...

It has been shown by many authors that the cross-correlation of two acoustic wave field recordings yields the Green's function between these receivers (in geophysics this is also known as 'seismic interferometry'). Recently the theory has been extended for situations where time-reversal invariance does not hold (e.g. in attenuating media) and where...