Resolution function for controlled‐source seismic interferometry: A data‐driven diagnosis

2009 ◽  
Author(s):  
Joost van der Neut ◽  
Jan Thorbecke
Keyword(s):  
Data Driven ◽  
Seismic Interferometry ◽  
Resolution Function ◽  
Controlled Source

scholarly journals Inversion of controlled-source electromagnetic reflection responses

Geophysics ◽  
2016 ◽  
Vol 81 (5) ◽  
pp. F49-F57 ◽  
Author(s):  
Jürg Hunziker ◽  
Jan Thorbecke ◽  
Joeri Brackenhoff ◽  
Evert Slob
Keyword(s):  
Electromagnetic Fields ◽  
Synthetic Data ◽  
Water Layer ◽  
Gradient Algorithm ◽  
Data Driven ◽  
Data Sets ◽  
Controlled Source ◽  
Material Parameters ◽  
Nonlinear Conjugate Gradient ◽  
Position And Orientation

Marine controlled-source electromagnetic reflection responses can be retrieved by interferometry. These reflection responses are free of effects related to the water layer and the air above it and do not suffer from uncertainties related to the source position and orientation. Interferometry is a data-driven process requiring proper sampling of the electromagnetic field as well as knowledge of the material parameters at the receiver level, i.e., the sediment just below the receivers. We have inverted synthetic data sets using the reflection responses or the original electromagnetic fields with the goal of extracting the conductivity model of the subsurface. For the inversion, a genetic algorithm and a nonlinear conjugate-gradient algorithm were used. Our results show that an inversion of the reflection responses produces worse estimates of the vertical conductivity but superior estimates of the horizontal conductivity (especially for the reservoir) with respect to the original electromagnetic fields.

scholarly journals Electromagnetic interferometry in wavenumber and space domains in a layered earth

Geophysics ◽  
2013 ◽  
Vol 78 (3) ◽  
pp. E137-E148 ◽  
Author(s):  
Jürg Hunziker ◽  
Evert Slob ◽  
Yuanzhong Fan ◽  
Roel Snieder ◽  
Kees Wapenaar
Keyword(s):  
Data Driven ◽  
Synthetic Aperture ◽  
Earth Model ◽  
Frequency Space ◽  
Controlled Source ◽  
Layered Earth ◽  
Electromagnetic Data ◽  
Air Water Interface ◽  
Stabilization Parameter ◽  
Subsurface Reservoir

With interferometry applied to controlled-source electromagnetic data, the direct field and the airwave and all other effects related to the air-water interface can be suppressed in a data-driven way. Interferometry allows for retreival of the scattered field Green’s function of the subsurface or, in other words, the subsurface reflection response. This reflection response can then be further used to invert for the subsurface conductivity distribution. To perform interferometry in 3D, measurements on an areal grid are necessary. We discuss 3D interferometry by multidimensional deconvolution in the frequency-wavenumber and in the frequency-space domains and provide examples for a layered earth model. We use the synthetic aperture source concept to damp the signal at high wavenumbers to allow large receiver sampling distances. Interferometry indeed increases the detectability of a subsurface reservoir. Finally, we discuss the dependency of the accuracy of the retrieved reflection response on the two crucial parameters: the conductivity of the seabed at the receiver location and the stabilization parameter of the least-squares inversion.

scholarly journals On the relation between seismic interferometry and the migration resolution function

Geophysics ◽  
2007 ◽  
Vol 72 (6) ◽  
pp. T61-T66 ◽  
Author(s):  
Jan Thorbecke ◽  
Kees Wapenaar
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Green's Functions ◽  
Green’S Functions ◽  
Seismic Interferometry ◽  
Resolution Function ◽  
Migration Literature ◽  
Double Focusing ◽  
Wavefield Extrapolation ◽  
Backward Propagation

Seismic interferometry refers to the process of retrieving new seismic responses by crosscorrelating seismic observations at different receiver locations. Seismic migration is the process of forming an image of the subsurface by wavefield extrapolation. Comparing the expressions for backward propagation known from migration literature with the Green’s function representations for seismic interferometry reveals that these seemingly distinct concepts are mathematically equivalent. The frequency-domain representation for the resolution function of migration is identical to that for the Green’s function retrieved by seismic interferometry (or its square, in the case of double focusing). In practice, they differ because the involved Green’s functions in seismic interferometry are all defined in the actual medium, whereas in migration one of the Green’s functions is defined in a background medium.

scholarly journals Interferometric correlogram-space analysis

Geophysics ◽  
2011 ◽  
Vol 76 (1) ◽  
pp. SA9-SA17 ◽  
Author(s):  
Oleg V. Poliannikov ◽  
Mark E. Willis
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
The Other ◽  
Seismic Interferometry ◽  
Controlled Source ◽  
Space Analysis

Controlled-source seismic interferometry is a method of obtaining a virtual shot gather from a collection of physical shot gathers. The set of traces corresponding to two common receiver gathers from many physical shots is used to synthesize a virtual shot located at one of the receivers and a receiver at the other. An estimate of the Green’s function between these two receivers is obtained by first crosscorrelating corresponding pairs of traces from each of the shots and then stacking the resulting crosscorrelograms. We studied the structure of crosscorrelograms obtained from a VSP acquisition geometry using surface sources and downhole receivers. The model is purely acoustic and contains flat or dipping layers and/or point inclusions that act as diffractors. We propose a semblance analysis based on moveout curves for both point diffractors and flat or dipping layers, which can be used to improve the quality of redatumed traces either by rejecting certain events prior to stacking or by enhancing them.

Passive seismic interferometry in XSoDEx experiment in northern Finland

2020 ◽  
Author(s):  
Elena Kozlovskaya ◽  
Nikita Afonin ◽  
Jari Karjalainen ◽  
Suvi Heinonen ◽  
Stefan Buske
Keyword(s):  
Seismic Data ◽  
Seismic Exploration ◽  
Theoretical Modelling ◽  
Seismic Interferometry ◽  
Upper Crust ◽  
S Wave ◽  
Good Opportunity ◽  
Controlled Source ◽  
Velocity Models ◽  
Passive Seismic

<p>There is the problem that application of controlled-source seismic exploration is not always possible in nature protected areas. As an alternative, application of passive seismic techniques in such areas can be proposed. In our study we show results of application of passive seismic interferometry for mapping the uppermost crust in the area of active mineral exploration in northern Finland using the data recorded during XSoDEx (eXperiment of SOdankylä Deep Exploration) project. The objectives of the project were to obtain a structural image of the upper crust in the Sodankylä area of Northern Finland in order to achieve a better understanding of the mineral system at depth. Within XSoDEx, a combined seismic reflection and refraction survey was organised by Geological Survey of Finland, University of Oulu, Finland (Oulu Mining School and Sodankylä Geophysical Observatory) and TU Bergakademie Freiberg, Germany. The vibrotrack of TU BAF was used as a source. The experiment was performed during July and August 2017 resulting in an approximately 80 km long seismic profile line. The seismic refraction data were simultaneously recorded by 60 vertical- and 40 three-component wireless autonomous receivers along an extended line around the reflection spread with maximum offsets of around 10 km. During night time, the receivers were recording passive seismic data. Thus the XSoDEx experiment provided a good opportunity to verify results of passive seismic interferometry with controlled-source seismic data, to identify limitations of this technique in areas of generally low level of high-frequency anthropogenic noise and to propose possible improvements of known techniques. Analysis of the data and theoretical modelling demonstrated that the dominating sources of ambient noise are non-stationary and have different origin in different parts of XSoDEx lines. In addition, the length of passive data for cross-correlation was limited to several hours and the long data recording period is usually considered as one of the main conditions for seismic interferometry applications. In order to obtain reliable Empirical Green Functions (EGF) from such short-term and non-stationary data, we applied a special technique (signal-to-noise ratio stacking). The calculated EGFs were inverted in order to obtain S-wave velocity models along XSodEx lines down to a depth of several hundreds metres. The obtained results are S-wave seismic velocity models of the upper crust in Northern Finland that agree well with geological data and complement the results of reflection seismic data interpretation.</p>

Seismic imaging of a near-vertical vein using controlled-source seismic interferometry

2021 ◽  
Vol 40 (2) ◽  
pp. 150a1-150a7
Author(s):  
Kriselle Dias ◽  
Charles Hurich ◽  
Sharon Deemer
Keyword(s):  
High Resolution ◽  
Seismic Interferometry ◽  
Reserve Estimation ◽  
Resource Evaluation ◽  
Target Delineation ◽  
Controlled Source ◽  
Vertical Vein ◽  
Seismic Image ◽  
Normal Method ◽  
New Methodologies

New methodologies for narrow-vein mining are making thin, steeply dipping mineralized veins economically viable mining targets. Drilling is the normal method for delineation and resource evaluation prior to mining. However, for the evaluation of narrow veins, significant drilling of barren rock is required. Controlled-source seismic interferometry has the potential to significantly decrease the costs of target delineation by providing high-resolution seismic images of thin, steeply dipping mineralized veins. We present a case study that employs seismic interferometry in conjunction with a walkaway vertical seismic profiling survey to image a thin (0.5–4 m), steeply dipping barite vein. The footprint of the seismic data acquisition is relatively small and compatible with operations in areas with limited access (e.g., mining camps). The technique requires some care with experimental design and data processing, but it is clearly demonstrated to produce a high-resolution seismic image. Furthermore, we demonstrate that inversion of the depth-migrated image can be used to quantify vein thickness and provide direct information for resource evaluation and reserve estimation.

scholarly journals Deghosting, Demultiple, and Deblurring in Controlled-Source Seismic Interferometry

2011 ◽  
Vol 2011 ◽  
pp. 1-28 ◽  
Author(s):  
Joost van der Neut ◽  
Maria Tatanova ◽  
Jan Thorbecke ◽  
Evert Slob ◽  
Kees Wapenaar
Keyword(s):  
Point Spread Function ◽  
Cross Correlation ◽  
Velocity Model ◽  
Seismic Interferometry ◽  
Controlled Source ◽  
Point Spread ◽  
Spread Function ◽  
Different Types

With controlled-source seismic interferometry we aim to redatum sources to downhole receiver locations without requiring a velocity model. Interferometry is generally based on a source integral over cross-correlation (CC) pairs of full, perturbed (time-gated), or decomposed wavefields. We provide an overview of ghosts, multiples, and spatial blurring effects that can occur for different types of interferometry. We show that replacing cross-correlation by multidimensional deconvolution (MDD) can deghost, demultiple, and deblur retrieved data. We derive and analyze MDD for perturbed and decomposed wavefields. An interferometric point spread function (PSF) is introduced that can be obtained directly from downhole data. Ghosts, multiples, and blurring effects that may populate the retrieved gathers can be locally diagnosed with the PSF. MDD of perturbed fields can remove ghosts and deblur retrieved data, but it leaves particular multiples in place. To remove all overburden-related effects, MDD of decomposed fields should be applied.

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