Seismic Acquisition Geometries Research Articles

Reconstructing seismic data using the accelerated linearized Bregman method and iterative soft thresholding algorithm

Seismic data reconstruction plays a crucial role in seismic exploration and imaging, facilitating accurate subsurface characterization and geological interpretation. In this study, we propose a novel approach for reconstructing seismic data using the accelerated linearized Bregman method (ALBM) in conjunction with the iterative soft thresholding algorithm (ISTA). This combined method, referred to as ALBM+ISTA, aims to exploit the complementary strengths of ALBM’s accelerated convergence properties and ISTA’s sparsity-promoting capabilities. The proposed approach is evaluated through theoretical simulations and case studies, wherein specific quantitative metrics such as signal-to-noise ratio (SNR), structural similarity index, root mean square error, peak signal-to-noise ratio, and edge preservation index are employed to assess reconstruction quality and accuracy. Results demonstrate that ALBM+ISTA offers improved performance in terms of noise suppression, structural fidelity, and edge preservation compared to existing reconstruction techniques. Furthermore, the method exhibits adaptability to diverse seismic acquisition geometries and noise levels, making it a promising tool for enhancing seismic data processing in various geological science applications.

Compensating Acquisition Footprint for Amplitude-Preserving Angle Domain Common Image Gathers Based on 3D Reverse Time Migration

Angle domain common image gathers (ADCIGs) play a crucial role in seismic exploration, offering prestack underground illumination information that aids in validating migration velocity and conducting prestack amplitude versus angle (AVA) analysis for reservoir characterization. This paper introduces an innovative approach for compensating amplitude errors caused by irregular seismic acquisition geometries in ADCIGs. By incorporating an angle domain illumination compensation factor, the proposed method effectively modifies these errors, preserving the amplitude of seismic reflectivity in the prestack angle domain. The effectiveness of the proposed approach is validated through comprehensive tests conducted on synthetic and field data examples. The results demonstrate the capability of the method to enhance the quality of ADCIGs derived from 3D reverse time migration (RTM), yielding accurate and reliable amplitude preservation. While the illumination compensation factor assumes a vertically linear velocity model, the method holds promise for extension to more complex media and diverse migration techniques. This suggests its applicability and adaptability beyond the specific assumptions considered in this study. In conclusion, this paper presents an innovative angle domain illumination compensation factor that significantly improves the quality of ADCIGs by addressing amplitude errors arising from irregular seismic acquisition geometries. The experimental validation using synthetic and field data confirms the effectiveness of the proposed method within the context of 3D RTM. Furthermore, the technique holds potential for broader application in more complex subsurface scenarios and various migration methodologies.

Quantifying the Effects of Near-Surface Viscosity on Seismic Acquisition Geometry: A case study from Chepaizi Exploration Area, Junggar Basin (NW China)

Quantifying the Effects of Near-Surface Viscosity on Seismic Acquisition Geometry: A case study from Chepaizi Exploration Area, Junggar Basin (NW China)

Design of Undersampled Seismic Acquisition Geometries via End-to-End Optimization

Design of Undersampled Seismic Acquisition Geometries via End-to-End Optimization

Indirect joint petrophysical inversion of synthetic shallow-seismic and multi-offset ground-penetrating radar data

SUMMARYBoth full-waveform inversion (FWI) of shallow-seismic and ground-penetrating radar (GPR) surface recordings have received particular attention in the past decade since they can reconstruct seismic and electromagnetic properties at high resolution. For consistent near-surface imaging, seismic and GPR wavefields can be combined by joint petrophysical inversion (JPI) using classical time-domain FWI. In conventional JPI of wavefields, both shallow-seismic and multi-offset GPR data contribute to reconstructing the same petrophysical parameters. In this paper, we show that seismic and GPR wavefields have different sensitivities to these parameters assuming the widely established petrophysical model combining the Gassmann fluid substitution model, the complex refractive index model and Archie’s equation. Based on this observation, we propose a new coupling strategy of petrophysical parameters which we call indirect JPI. In indirect JPI, seismic data is primarily used for porosity reconstruction, while GPR data is used only for saturation reconstruction. Unlike conventional JPI, we first update the seismic and GPR parameters using non-petrophysical parametrizations and then transform the most reliable estimates to petrophysical parameters. 2-D synthetic tests show that indirect JPI can provide more accurate and consistent results than conventional JPI. In addition, indirect JPI is more robust when uncertainties exist in petrophysical a priori knowledge. More importantly, indirect JPI has the flexibility to integrate different types of seismic and electromagnetic waves and acquisition geometries depending on the target of interest, resulting in the best solution. Indirect JPI has been proven to be a promising approach for multiparameter reconstructions (seven parameters in this study).

Automated Seismic Acquisition Geometry Design for Optimized Illumination at the Target: A Linearized Approach

Automated Seismic Acquisition Geometry Design for Optimized Illumination at the Target: A Linearized Approach

Bayesian full-waveform inversion with realistic priors

Seismic full-waveform inversion (FWI) uses full seismic records to estimate the subsurface velocity structure. This requires a highly nonlinear and nonunique inverse problem to be solved; therefore, Bayesian methods have been used to quantify uncertainties in the solution. Variational Bayesian inference uses optimization to efficiently provide solutions. However, previously the method has only been applied to a transmission FWI problem and with strong prior information imposed on the velocity such as is never available in practice. We have found that the method works well in a seismic reflection setting and with realistically weak prior information, representing the type of problem that occurs in reality. We conclude that the method can produce high-resolution images and reliable uncertainties using data from standard reflection seismic acquisition geometry, realistic nonlinearity, and practically achievable prior information.

Reflection Angle-Domain Pseudoextended Least-Squares Reverse Time Migration Using Hybrid Regularization

Angle-domain common image gathers (ADCIGs) describe the reflectivity variation over reflection angles which are important for seismic exploration. The ADCIGs could be obtained using reverse time migration (RTM). However, because of the limitation of seismic frequency band and acquisition geometry, RTM produces the ADCIGs with low fidelity. We propose a reflection angle-domain pseudoextended least-squares RTM method to improve the quality of the ADCIGs in which the Poynting vector is used to efficiently calculate the angles. We first extend the inverted model in the reflection angle domain and derive a feasible pseudoextended Born modeling operator which can map the reflection angle-domain extended model to seismic data. The modeling operator, associated with an adjoint operator, are then used to build a pseudoextended linearized inversion framework for inverting the angle-dependent reflectivity. Taking advantage of the simplicity and coherency of the ADCIGs, we impose a series of low-rank constraints on the extended angle dimension and a sparse constraint on the whole dimension to ensure the production of high-quality ADCIGs. The proposed method is finally solved by a regularized conjugate gradient algorithm. We conduct several numerical examples on a flat layer model, the Marmousi model, and the Sigsbee2A salt model to test the validity and superiority of the proposed method. The results demonstrate that the proposed method could produce the ADCIGs and the stacked image with higher fidelity than RTM, which provides a reliable input for migration velocity analysis, anisotropic model building, and amplitude versus angle analysis.

Order‐controlled closed‐loop focal beams and resolution comparison of primary and multiple reflections for seismic acquisition geometries

ABSTRACTFocal beam analysis has built a bridge between the acquisition parameters on the surface and the image quality of underground targets. However, as a practical matter, it is still difficult to answer how to choose a proper acquisition geometry according to the complexity of medium, especially considering the contradictory effects of multiple reflections on spatial resolution as they can be considered to be either potential signal or additional noise, depending on the envisioned imaging technology. We introduce an order‐controlled, closed‐loop focal beam method in which the migration operator and the resolution function can be analysed in the process of the closed‐loop migration with full control over the order of the surface and internal multiples considered. This method highlights the effects of primary and different‐order multiple wavefields on the imaging resolution for different acquisition geometries and various overburden strata. We apply the method to analyse the predicted resolution of seismic acquisition geometries considering multiples as either noise or signal. Results show, in the acquisition geometry design, that when the primaries cannot provide a complete spatial illumination for the subsurface target, e.g. because of the limited‐aperture acquisition geometries or the complicated overburden, we should use the closed‐loop focal beam analysis to assess the contradictory effects of multiples as both signal and noise, in which the maximum order of multiples ought to be chosen according to the core aim of the acquisition analysis. We can apply the second‐order closed‐loop focal beam analysis to quantify the effects of acquisition geometries on multiple‐wave suppression and can also perform the high‐order closed‐loop focal beam analysis to quantify the effects of acquisition geometries on high‐resolution imaging (migration). This method can also be used to choose the optimal order of multiples in the closed‐loop migration.

Numerical Method for Horizontal and Vertical Spatial Resolutions of Seismic Acquisition Geometries in Complex 3D Media

Spatial sampling, finite bandwidth, and overlying-strata shielding are three key issues to affect the spatial resolution of seismic imaging for deep targets. Some factors have a great impact on the horizontal resolution, whereas others influence the vertical resolution. How to quantify these effects remains controversial for complex media. Most previous studies on seismic acquisition geometries focus on the horizontal resolution for layered media but neglecting to measure the vertical resolution especially in complex media. Conventional criteria for vertical resolution are based on the theory of geometric seismology with the assumption of a simple medium. As a practical alternative for resolution estimation in complex media, numerical methods with wavefield extrapolation for focal-beam analysis can provide comprehensive insight into the combined effect of acquisition geometries, bandlimited frequencies, and complex media on the horizontal and vertical spatial resolutions of acquisition geometries. We incorporate some classic criteria into the focal-beam numerical analysis to measure the spatial resolutions. Four parameters are used to quantify the performance of acquisition geometries. The horizontal (vertical) resolution is defined as the main-lobe width of a focal beam along the horizontal (vertical) direction, whereas the square root of the peak-to-total ratio of energies is referred to as the horizontal (vertical) sharpness. These parameters describe the horizontal and vertical spatial resolution and sharpness to image the target. Numerical examples with typical acquisition geometries demonstrate the performance of numerical resolution analyses in complex media.

Parameter crosstalk and modeling errors in viscoacoustic seismic full-waveform inversion

Simultaneous use of data within relatively broad frequency bands is essential to discriminating between velocity and [Formula: see text] errors in the construction of viscoacoustic full-waveform inversion (QFWI) updates. Individual frequencies or narrow bands in isolation cannot provide sufficient information to resolve parameter crosstalk issues in a surface seismic acquisition geometry. At the same time, too broad a frequency band introduces significant problems in the presence of modeling errors. The risk of modeling errors arising in QFWI is high because of the range of very different geologic contributors to attenuation and dispersion and the variety of available mathematical descriptions. We perform numerical tests that suggest that by relaxing the typical requirement that the frequency dependence of the assumed intrinsic attenuation model be self-consistent across the full spectrum, significant improvement in the fidelity of the inversion results can be obtained in cases where the attenuation model assumed in the inversion differs substantially from the true subsurface behavior. We find that the size of the frequency bands used in this inversion approach is a useful hyperparameter controlling trade-off between crosstalk reduction and flexibility in coping with uncertain physics.

INNOVATIVE WORKFLOW FOR SEISMIC ACQUISITION DESIGN

Any new survey geometry design must be based on thorough integrated analysis and modeling of project goals and objectives, exploration and/or field development targets’ requirements, available technologies, operational constraints, terrain conditions and project budgets. A critical matrix for a good quality seismic acquisition geometry design is dense and uniform distribution of seismic traces in areal extent and within CDP, bins with sufficiently high trace density, high fold, wide azimuth, long inline/crossline/maximum offsets and small largest minimum offset. That said, operational considerations could be a hindrance for such quality as in heavily congested fields, extensive network of wells, platforms, production facilities and terrain obstacles leading to gaps in coverage and severe irregularities of fold, offset and azimuth distributions. This work demonstrates the essential value of using all available data and information about the project area. Such as well logs, RMS and interval velocities, legacy 2D and 3D seismic acquisition and processing reports, satellite and positioning maps, scouting reports, multi-physics maps and data and near surface environmental reports are all relevant. Thus, detailed, accurate and realistic estimates of the design’s attributes are generated including desired temporal and spatial resolution, focused target illumination parameters, signal penetration, recording requirements and noise minimization processes.
 Keywords: Fold, Offset, Azimuth, Acquisition footprints, Well logs, Interval velocities, spatial resolution

To: “On vertical resolution of seismic acquisition geometries in complex 3D media,” Jun Su, Li-Yun Fu, Wei Wei, Weijia Sun, and Junhua Hu, GEOPHYSICS, 82, no. 6, P75–P87, doi: 10.1190/geo2017-0028.1.

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To: “On vertical resolution of seismic acquisition geometries in complex 3D media,” Jun Su, Li-Yun Fu, Wei Wei, Weijia Sun, and Junhua Hu, Geophysics, 82, no. 6, P75–P87, doi: 10.1190/geo2017-0028.1.

PreviousNext No AccessGEOPHYSICSVolume 83, Issue 4To: “On vertical resolution of seismic acquisition geometries in complex 3D media,” Jun Su, Li-Yun Fu, Wei Wei, Weijia Sun, and Junhua Hu, Geophysics, 82, no. 6, P75–P87, doi: 10.1190/geo2017-0028.1.Authors: Jun SuLi-Yun FuWei WeiWeijia SunJunhua HuJun SuSearch for more papers by this author, Li-Yun FuSearch for more papers by this author, Wei WeiSearch for more papers by this author, Weijia SunSearch for more papers by this author, and Junhua HuSearch for more papers by this authorhttps://doi.org/10.1190/geo2018-0614-retraction.1 SectionsAboutFull TextPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail "To: “On vertical resolution of seismic acquisition geometries in complex 3D media,” Jun Su, Li-Yun Fu, Wei Wei, Weijia Sun, and Junhua Hu, Geophysics, 82, no. 6, P75–P87, doi: 10.1190/geo2017-0028.1.." Geophysics, 83(4), p. Y5FiguresReferencesRelatedDetailsRelated articlesGEOPHYSICS21 Aug 2017On vertical resolution of seismic acquisition geometries in complex 3D media Volume 83Issue 4Jul 2018Pages: 1JA-Z18ISSN (print):0016-8033 ISSN (online):1942-2156 Publisher:Society of Exploration Geophysicists HistoryPublished Online: 13 Jul 2018Published in print: 01 Jul 2018 CITATION INFORMATION Jun Su, Li-Yun Fu, Wei Wei, Weijia Sun, and Junhua Hu, (2018), "To: “On vertical resolution of seismic acquisition geometries in complex 3D media,” Jun Su, Li-Yun Fu, Wei Wei, Weijia Sun, and Junhua Hu, Geophysics, 82, no. 6, P75–P87, doi: 10.1190/geo2017-0028.1.," GEOPHYSICS 83: Y5-Y5. https://doi.org/10.1190/geo2018-0614-retraction.1 Plain-Language Summary PDF Download Metrics Loading ...

Focal beam analysis for 3D acquisition geometries in complex media with GPU implementation

Seismic acquisition geometries have a significant influence on the quality of seismic data in the oil and gas exploration process. Therefore, prior analyses are beneficial to the design of acquisition geometries before implementation of seismic acquisition. The focal beam analysis method can provide quantitative insights into the combined influence of acquisition geometries and subsurface structures. This approach involves a large calculation burden concerning 3D wavefield extrapolation in the case of complex media, thus inhibiting the practical application of focal beam analysis in complex media when using regular CPUs. Therefore, using a graphics processing unit (GPU) to accelerate focal beam analysis becomes imperative. We have developed a fast parallel algorithm to speed up the focal beam analysis for 3D acquisition geometries in complex media on GPUs. Three-dimensional numerical examples show that the GPU-based focal beam analysis runs about 17 times faster than a serial CPU-based one. We also demonstrate the validity and scalability of the proposed approach with numerical examples. The boost in performance afforded by the GPU architecture allows us to analyse 3D acquisition geometries in complex media with less time and at lower cost of hardware.

Limitations of correlation-based redatuming methods

Redatuming aims to correct seismic data for the consequences of an acquisition far from the target. That includes the effects of an irregular acquisition surface and of complex geological structures in the overburden such as strong lateral heterogeneities or layers with low or very high velocity. Interferometric techniques can be used to relocate sources to positions where only receivers are available and have been used to move acquisition geometries to the ocean bottom or transform data between surface–seismic and vertical seismic profiles. Even if no receivers are available at the new datum, the acquisition system can be relocated to any datum in the subsurface to which the propagation of waves can be modeled with sufficient accuracy. By correlating the modeled wavefield with seismic surface data, one can carry the seismic acquisition geometry from the surface closer to geologic horizons of interest. Specifically, we show the derivation and approximation of the one-sided seismic interferometry equation for surface-data redatuming, conveniently using Green's theorem for the Helmholtz equation with density variation. Our numerical examples demonstrate that correlation-based single-boundary redatuming works perfectly in a homogeneous overburden. If the overburden is inhomogeneous, primary reflections from deeper interfaces are still repositioned with satisfactory accuracy. However, in this case artifacts are generated as a consequence of incorrectly redatumed overburden multiples. These artifacts get even worse if the complete wavefield is used instead of the direct wavefield. Therefore, we conclude that correlation-based interferometric redatuming of surface–seismic data should always be applied using direct waves only, which can be approximated with sufficient quality if a smooth velocity model for the overburden is available.

Reciprocity and double plane-wave migration

In plane-wave migration techniques, plane-wave data sets with seismic energy in both positive and negative ray-parameter sections are more desirable than those with seismic energy only in either positive or negative ray-parameter sections. Such plane-wave data sets are often referred to as optimal plane-wave data sets because they can be used to illuminate the subsurface from both sides of the targets and, therefore, can produce sharp images. Traditionally, to obtain optimal plane-wave data sets from one-sided gathers generated by marine seismic acquisition geometry, one needs to invoke the reciprocity principle to sort split-spread gathers prior to implementing plane-wave decomposition. We have investigated the applicability of the reciprocity principle in the double plane-wave (DPW) domain. We have developed an easy and efficient merging method that generates optimal plane-wave data sets in the DPW domain using one-sided shot gathers. We call this resultant plane-wave data set the “optimal DPW data set.” We find that an optimal DPW data set transformed from one-sided gathers is a good approximation to a DPW data set transformed from split-spread gathers with the same maximum offset as that of the one-sided gathers. We find that ray-parameter common-image gathers with continuous events in both positive and negative ray-parameter sections can be generated by migrating optimal DPW data sets. This helps migration velocity analysis and improves the subsurface illumination. In addition, we show that the computational cost of DPW migration methods could be reduced with the help of the reciprocity principle. We test our proposed method using a synthetic model to demonstrate its effectiveness.

On vertical resolution of seismic acquisition geometries in complex 3D media

Exploration frequency and spatial sampling can affect the resolution of seismic imaging. Some factors have a great impact on the horizontal resolution, whereas other factors significantly influence the vertical resolution. How to quantify these effects still remains controversial for complex media. Most previous studies on seismic acquisition geometries focus on the horizontal resolution for seismic migration, but neglect to measure the vertical resolution especially in complex media. The conventional criteria for vertical resolution are based on the theory of geometric seismology with the assumption of a simple medium. Focal-beam analysis can provide comprehensive insight into the combined effects of acquisition geometries, band-limited frequencies, and complex media on vertical resolution. We define two parameters to quantify the vertical resolution of acquisition geometry: the main-lobe width (MLW) of a focal beam along the vertical direction and the ratio of its main-lobe amplitude to the total amplitude (RMT). MLW defines the vertical resolution to image the target, whereas RMT describes the clarity of the imaging. We evaluate examples of typical acquisition geometries to demonstrate how band-limited frequencies and acquisition parameters influence the vertical resolution, described in terms of MLW and RMT values. Comparisons of focal beams and classic criteria with increasing bandwidth and spatial sampling indicate that the MLW and RMT of focal beams can be more accurate to describe the vertical resolution of exploration seismology. Case studies of seismic migration with 3D seismic data from an oilfield in China demonstrate that the acquisition geometry with denser detectors has a larger value of RMT indicating more clarity in seismic imaging. Prior MLW and RMT analyses of acquisition geometry to predict the quality of acquired data sets can optimize the design of acquisition geometries before the implementation of seismic acquisition.

Seismic interpretation, attribute analysis, and illumination study for targets below a volcanic-sedimentary succession, Santos Basin, offshore Brazil

During the past decade, a significant exploration effort into deeper water and deeper targets in offshore areas brought more knowledge about the distribution of igneous rocks in the sedimentary basins along many continental margins. Nonhomogeneous illumination effects may occur below shallow, high-impedance igneous rock bodies. The seismic processing, depth imaging, interpretation, and attribute analysis require a special attention when these magmatic bodies affect the illumination of deeper targets. Usually, those structures are not considered in illumination studies, and the salt diapirs govern the analysis. In this work, seismic attributes are quite relevant to constrain the geologic model used to simulate the amplitude maps of the deeper target and to quantify the shadow effects observed on it. These amplitude shadows may either create (false) or hide (true) attribute anomalies. We have modeled a Tertiary volcano-sedimentary succession (VSS) mapped in the northeastern Santos Basin, offshore Brazil, to simulate the effect in the amplitude response of deeper targets. There were multiple magmatic events through the Santos Basin Cretaceous-Tertiary sedimentary succession, intrusive and extrusive. The igneous extrusive rocks intercalated with sediments forming VSS marked by low- and high-amplitude responses with tough lateral discontinuity. The amplitude found well-preserved architectural elements interpreted as lava flows and volcanoes, contrasting with layered sediments. We have defined geobodies constrained by relative impedance and 3D edge detection to build the 3D geologic model of the igneous successions used for seismic simulation. From the geobodies, we modeled two VSS to run the P-waves ray-tracing propagation to simulate the migrated amplitude map of the deeper Lower Albian sequence top. We computed the P-velocity and the density from well logs, and the seismic acquisition geometry was similar to the original. Comparison between real and simulated amplitudes showed the impact of shadow zones caused by shallower igneous bodies.

Seismic modelling of fault zones

While faults have long been known as primary pathways for fluid migration in sedimentary basins, recent work highlights the importance of fault zone internal architecture, lateral variation, transmissivity, and impact on migration and trapping. The impacts of fault zone architecture and properties on seismic images are investigated to facilitate accurately mapped fault zones, and to predict subseismic flow properties and sealing potential. A wedge-type fault model with a main fault and a synthetic fault displacing a typical North West Shelf siliciclastic succession is used to replicate the geometrical components of a seismic-scale fault. Elastic properties are derived from rock physics models, which are used in a 2D elastic modelling algorithm to produce realistic marine seismic acquisition geometry. These data were subsequently input into a 2D prestack (one-way wave-equation) migration code to produce an interpretable seismic image. Base-case elastic properties are systematically varied; modelling focuses on gouge properties, fractured fault zone material, the sandstone Vp/Vs relationship, and shale-sand velocity contrast. The workflow from geological model building to elastic property substitution and forward seismic modelling is extremely quick and versatile, allowing testing of a wide range of scenarios. So far this approach has yielded valuable insights into internal fault property prediction and interpretation of the fault zone in traditional post-stack seismic datasets. Implications for processing workflow and attenuation of fault shadows are also expected.