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Janos Kertesz. Granular materials, which are essentially large conglomerations of macroscopic solid particles, are relevant for many different areas of science and technology. Their study forms a wide interdisciplinary research field attracting the interest of physicists, applied mathematicians, geologists, as well as chemical, civil, mechanical, and agricultural engineers.
Dierk Raabe. Modelling physical phenomena across the scales is a veritable challenge for scientific computing. Due to the complexity of the problems involved, rigorous and predictive bottom-up approaches are quite rare and largely remain a task for future research. In this context, it is of great interest to develop models which allow to efficiently incorporate the essential effects originating from a large number of interactions at a smaller scale in a description of the system behavior at a larger scale.
Ha Bui. Joseph Etim. Abdelraheem Mahmoud Aly. Akhila Manne , Neelima Satyam. Jose L. Felix Darve. Log in with Facebook Log in with Google. Remember me on this computer. In that concept this research work attempts to derive a three dimensional model of the seismically active parts of the underlying underground faults in areas of petroleum interest. For that purpose seismic spatio-temporal clustering has been applied to seismic data to identify potential distinct seismic regions in the area of interest.
Results have been coalesced with two dimensional maps of underground faults from past surveys and seismic epicentres, having followed careful reallocation processing, have been used to provide information regarding the vertical extent of multiple underground faults in the region of interest.
The end product is a three dimensional map of the possible underground location and extent of the seismically active parts of underground faults. Indexing terms: underground faults modelling, seismic data mining, 3 D visualisation, active seismic source mapping, seismic hazard evaluation, dangerous phenomena modelling Acknowledgment This research work is supported by the ESPA Operational Programme, Education and Life Long Learning, Students Practical Placement Initiative.
References [1] Alves, T. The seismic method is a valuable tool for getting 3 D -images from the subsurface. Seismic data acquisition today is not only a topic for oil and gas exploration but is used also for geothermal exploration, inspections of nuclear waste sites and for scientific investigations.
The system presented in this contribution may also have an impact on the visualization of 3 D -data of other geophysical methods. They are a combination of individual vertical cuts, possibly linked to a cubical portion of the data volume, and the stereoscopic view of the seismic data. By these methods, the spatial perception for the structures and thus of the processes in the subsurface should be increased.
Stereoscopic techniques are e. The aim of the interpretation system shown here is stereoscopic visualization of seismic data at the workplace, i. The possibilities offered by the use of a stereoscopic system do not replace a conventional interpretation workflow. Rather they have to be implemented into it as an additional step.
The amplitude distribution of the seismic data is a challenge for the stereoscopic display because the opacity level and the scaling and selection of the data have to. Walker Ranch 3 D seismic images. Amplitude images both vertical and depth slices extracted from 3 D seismic reflection survey over area of Walker Ranch area adjacent to Raft River.
Crossline spacing of feet and inline of feet using a Vibroseis source. Processing included depth migration. Micro-earthquake hypocenters on images. Stratigraphic information and nearby well tracks added to images. Images are embedded in a Microsoft Word document with additional information. Exact location and depth restricted for proprietary reasons.
Data collection and processing funded by Agua Caliente. Original data remains property of Agua Caliente. Using 3 D visualization and seismic attributes to improve structural and stratigraphic resolution of reservoirs. Recent advances in hardware and software have given the interpreter and engineer new ways to view 3 D seismic data and well bore information.
Recent papers have also highlighted the use of various statistics and seismic attributes. By combining new 3 D rendering technologies with recent trends in seismic analysis, the interpreter can improve the structural and stratigraphic resolution of hydrocarbon reservoirs.
This paper gives several examples using 3 D visualization to better define both the structural and stratigraphic aspects of several different structural types from around the world. Statistics, 3 D visualization techniques and rapid animation are used to show complex faulting andmore » detailed channel systems.
These systems would be difficult to map using either 2 D or 3 D data with conventional interpretation techniques. In this work we are going to show the advantages of a dynamic tomography 4 D , versus a static image 3 D related with a volcanic reactivation and eruption at El Hierro island Canary Islands, Spain.
In this process a high number of earthquakes before and during the eruptive processes have been registered. We are going to show a 3 D image as an average of the velocity structure and then the characteristics and physical properties on the medium, including the presence or not of magma. This image will be complemented with its evolution along the time, observing its volcanic dynamic and its influence over the medium properties, including its power as an important element on early warnings protocols.
Since this moment an intense swarm took place, with more than events, until 11th December, with magnitudes MLg from 0. In this period two eruptive processes have been declared in front of the South coast of El Hierro island, and they have not finished yet. This seismic swarm has allowed carrying out a 3 D seismic tomography, using P and S waves traveltimes. It has showed a low velocity from the North to the South. On the other hand, we have performed a 4 D seismic tomography, taking the events occurred at different intervals of time.
We can observe the evolution of the negative anomaly along the time, from the North to the South, where has taken place La Restinga submarine eruption. We present a new, computationally efficient numerical method to simulate global seismic wave propagation in realistic 3 - D Earth models with laterally heterogeneous media and finite boundary perturbations.
Our method is a hybrid of pseudo-spectral and spectral element methods SEM. We characterize the azimuthal dependence of 3 - D wavefields in terms of Fourier series, such that the 3 - D equations of motion reduce to an algebraic system of coupled 2- D meridional equations, which can be solved by a 2- D spectral element method based on www.
Computational efficiency of our method stems from lateral smoothness of global Earth models with respect to wavelength as well as axial singularity of seismic point sources, which jointly confine the Fourier modes of wavefields to a few lower orders. All boundary perturbations that violate geometric spherical symmetry, including Earth's ellipticity, topography and bathymetry, undulations of internal discontinuities such as Moho and CMB, are uniformly considered by means of a Particle Relabeling Transformation.
We show novel benchmarks for global wave solutions in 3 - D mantle structures between our method and an independent, fully discretized 3 - D SEM with remarkable agreement. Performance comparisons are carried out on three state-of-the-art tomography models, with seismic period going down to 5s. It is shown that our method runs up to two orders of magnitude faster than the 3 - D SEM for such settings, and such computational advantage scales favourably with seismic frequency.
By examining wavefields passing through hypothetical Gaussian plumes of varying sharpness, we identify in model-wavelength space the limits where our method may lose its advantage.
Multi-hole seismic modeling in 3 - D space and cross-hole seismic tomography analysis for boulder detection. A boulder stone, a common geological feature in south China, is referred to the remnant of a granite body which has been unevenly weathered. Undetected boulders could adversely impact the schedule and safety of subway construction when using tunnel boring machine TBM method. Therefore, boulder detection has always been a key issue demanded to be solved before the construction.
Nowadays, cross-hole seismic tomography is a high resolution technique capable of boulder detection, however, the method can only solve for velocity in a 2- D slice between two wells, and the size and central position of the boulder are generally difficult to be accurately obtained. In this paper, the authors conduct a multi-hole wave field simulation and characteristic analysis of a boulder model based on the 3 - D elastic wave staggered-grid finite difference theory, and also a 2- D imaging analysis based on first arrival travel time.
The results indicate that 1 full wave field records could be obtained from multi-hole seismic wave simulations. Simulation results describe that the seismic wave propagation pattern in cross-hole high-velocity spherical geological bodies is more detailed and can serve as a basis for the wave field analysis.
The received diffracted wave interferes with the primary wave and in consequence the picked first arrival travel time is not derived from the profile, which results in a false appearance of high-velocity geology features.
Finally, the results of 2- D analysis in 3 - D modeling space are comparatively analyzed with the physical model test vis-a-vis the effect of high velocity body on the seismic tomographic measurements.
Interpretation of the 3 D seismic data resulted in a detailed image of the reef, using several interpretive techniques. A seismic reflection within the reef was correlated with a known porosity zone, and the relationship between porosity and seismic amplitude was investigated.
A possible connection between the main reef and the low relief gas well was identified. This project illustrates the economic value of investigating an existing storage reef with 3 D seismic data, and underscores the necessity of acquiring such a survey prior to developing a new storage reservoir.
Goals of the survey were to 1 determine if additional storage capacity could be found either as extensions to the Ray reef or as undiscovered satellite reefs, 2 investigate the relationship between the main body and a low-relief gas well east of the reef, and 3 determine if seismic data can be used to quantify reservoir parameters to maximize the productive capacity of infillmore » wells.
Interpretation of the 3 - D seismic data resulted in a detailed image of the reef, using several interpretive techniques. A seismic reflection within the reef was correlated with a known porosity zone, and a possible relationship between porosity and seismic amplitude was investigated. A potential connection between the main reef and the low-relief gas well was identified.
This project illustrates the economic value of investigating an existing storage reef with 3 - D seismic data, and underscores the necessity of such a survey prior to developing a new storage reservoir. True-triaxial experimental seismic velocities linked to an in situ 3 D seismic velocity structure.
Upscaling from laboratory seismic velocities to in situ field seismic velocities is a fundamental problem in rock physics. This study presents a unique situation where a 3 D velocity structure of comparable frequency ranges is available both in situ and experimentally. The velocity survey and oriented, cubic rock sample, are from the m level of the mine, where the geology is a homogeneous and isotropic granite.
The triaxial in situ stress field at this level was determined and the Mine-by tunnel was excavated horizontally to maximize borehole break out. Ultrasonic velocity measurements for P-, S1-,and S2-waves were done in the tunnel sidewall, ceiling and far-field rock mass.
The cubic 80 mm granite sample was prepared oriented to the in situ principle stress axis in the field. The stress path of the sample extraction from in situ stress was modeled in FLAC 3 D by Itasca inc , and then reapplied in the GIC to obtain the laboratory velocities at in situ stress. The theory of acoustoelasticity, the dependence of acoustic wave velocity on stresses in the propagating isotropic medium, is applied to the borehole hoop and radial stresses produced by the Mine-by tunnel.
The acoustoelastic effect involves determining the linear second-order and nonlinear third-order elastic constants, which are derived from the velocity-stress slopes. New comprehensive standard seismic noise models and 3 D seismic noise variation for Morocco territory, North Africa, obtained using seismic broadband stations.
In the current work, we constructed new comprehensive standard seismic noise models and 3 D temporal-spatial seismic noise level cubes for Morocco in north-west Africa to be used for seismological and engineering purposes.
Consequently, this preliminary study was conducted to shed light on seismic noise levels specific to north-west Africa. For this purpose, 23 broadband seismic stations recently installed in different structural domains throughout Morocco are used to study the nature and characteristics of seismic noise and to create seismic noise models for Morocco.
Continuous data recorded during , and were processed and analysed to construct these new noise models and 3 D noise levels from all stations. This variation is attributed to differences in the nature of seismic noise sources that dominate Morocco in these period bands. The results of this study have a new perception about permanent seismic noise models for this spectacular region and can be considered a significant contribution because it supplements the Peterson models and can also be used to site future permanent seismic stations in Morocco.
Absolute earthquake locations using 3 - D versus 1- D velocity models below a local seismic network: example from the Pyrenees. Theunissen, T. Local seismic networks are usually designed so that earthquakes are located inside them primary azimuthal gap seismic stations km. Moving towards 3 - D location algorithms requires robust 3 - D velocity models. This work takes advantage of seismic monitoring spanning more than 30 yr in the Pyrenean region.
We investigate the influence of a well-designed 3 - D model with station corrections including basins structure and the geometry of the Mohorovicic discontinuity on earthquake locations. The horizontal accuracy in the 1- D case can be higher than in the 3 - D case if lateral variations in the structure are not properly resolved.
Errors on velocity models and accuracy of absolute earthquake locations are assessed based on a reference data set made of active seismic , quarry blasts and passive temporary experiments. Some updates have been added to NLLoc to better focus on the final solution outlier exclusion, multiscale grid search, S-phases weighting. Errors in the probabilistic approach are defined to take into account errors on velocity models and on arrival times.
The seismicity in the final 3 - D catalogue is located with a horizontal uncertainty of about 2. Noises and data gaps complicate the seismic data processing and subsequently cause difficulties in the geological interpretation. We discriminated the noises from single individual time slices of 3 D volumes by analyzing Eigen triplets of the trajectory matrix. We first tested the efficacy of the method on 3 D synthetic seismic data contaminated with noise and then applied to the post stack seismic reflection data acquired from the Sleipner CO2 storage site pre and post CO2 injection from Norway.
The bright spots identified in the de-noised data indicate upward migration of CO2 towards the top of the Utsira formation. In this paper, measurements show fast ion losses correlated with applied three-dimensional 3 D fields in a variety of plasmas ranging from L-mode to resonant magnetic perturbation RMP edge localized mode ELM suppressed H-mode discharges.
Full orbit following using M 3 D -C1 calculations of the perturbed fields and kinetic profiles reproduce many features of the measured losses and points to the importance of the applied 3 D field phase with respect to the beam injection location in determining the overall impact on prompt beam ion loss.
Modeling of these results includes a self-consistent calculation of the 3 D perturbed beam ion birth profiles and scrape-off-layer ionization, a factor found to be essential to reproducing the experimental measurements.
The Nankai Trough off southwest Japan is one of the best subduction-zone to study megathrust earthquake fault. Historic, great megathrust earthquakes with a recurrence interval of yr have generated strong motion and large tsunamis along the Nankai Trough subduction zone. Particularly, physical properties of the incoming hemipelagic sediments may be critical for seismogenic behavior of the megathrust fault.
We have carried out core-log- seismic integration CLSI to estimate 3 D acoustic impedance and porosity for the incoming sediments in the Nankai Trough. We computed acoustic impedance depth profiles for the IODP drilling sites from P-wave velocity and density data.
We constructed seismic convolution models with the acoustic impedance profiles and a source wavelet which is extracted from the seismic data, adjusting the seismic models to observed seismic traces with inversion method. As a result, we obtained 3 D acoustic impedance volume and then converted it to 3 D porosity volume. In general, the 3 D porosities show decrease with depth. We found a porosity anomaly zone with alteration of high and low porosities seaward of the trough axis.
In this talk, we will show detailed 3 D porosity of the incoming sediments, and present implications of the porosity anomaly zone for the.
Marchenko methods are novel, data driven techniques that allow seismic wavefields from sources and receivers on the Earth's surface to be redatumed to construct wavefields with sources in the subsurface - including complex multiply-reflected waves, and without the need for a complex reference model. In turn, this allows subsurface images to be constructed at any such subsurface redatuming points image or virtual receiver points.
Such images are then free of artefacts from multiply-scattered waves that usually contaminate migrated seismic images. Marchenko algorithms require as input the same information as standard migration methods: the full reflection response from sources and receivers at the Earth's surface, and an estimate of the first arriving wave between the chosen image point and the surface.
The latter can be calculated using a smooth velocity model estimated using standard methods. The algorithm iteratively calculates a signal that focuses at the image point to create a virtual source at that point, and this can be used to retrieve the signal between the virtual source and the surface.
A feature of these methods is that the retrieved signals are naturally decomposed into up- and down-going components. That is, we obtain both the signal that initially propagated upwards from the virtual source and arrived at the surface, separated from the signal that initially propagated downwards. The redatumed signal in figure b has been calculated using Marchenko methods from a virtual source m, m and m to the surface.
For comparison the true solution is given in figure c , and shows a good match when compared to figure b. While these 2 D redatuming and imaging methods are still in their infancy having first been developed in. Careful review of old geophysical and geological data from the Western Desert of Egypt led to the decision of shooting a 3 - D seismic survey targeted to solve some of the encountered geophysical problems such as difficulty of tracing the very thin pay zone, identifying the stratigraphic plays and the main two problems of the seismic method in the Western Desert which are statics and poor imaging.
In a case history form illustrated by examples, the result of the 3 - D solutions will be shown. Furthermore, an analytical approach will be undertaken to clarify and highlight the sources of those geophysical problemsmore » and how the 3 - D solution helped in resolving them.
The geo-referenced 3 D model was constructed from weighted control points that integrate depth information from hypocenter locations and regional seismic velocity studies. We used the 3 D model to differentiate earthquakes that occur above the Juan de Fuca Plate surface from earthquakes that occur below the plate surface. This GIS project of the Cascadia subduction system supersedes the one previously published by McCrory and others Our new slab model updates the model with new constraints.
The most significant updates to the model include: 1 weighted control points to incorporate spatial uncertainty, 2 an additional gridded slab surface based on the Generic Mapping Tools GMT Surface program which constructs surfaces based on splines in tension see expanded description below , 3 double-differenced hypocenter locations in northern California to better constrain slab location there, and 4 revised slab shape based on new hypocenter profiles that incorporate routine depth uncertainties as well as data from new seismic -reflection and seismic -refraction studies.
We also provide a 3 D fly-through animation of the model for use as a visualization tool. Initialising reservoir models for history matching using pre-production 3 D seismic data: constraining methods and uncertainties. Integration of 3 D and time-lapse 4 D seismic data into reservoir modelling and history matching processes poses a significant challenge due to the frequent mismatch between the initial reservoir model, the true reservoir geology, and the pre-production baseline seismic data.
A fundamental step of a reservoir characterisation and performance study is the preconditioning of the initial reservoir model to equally honour both the geological knowledge and seismic data. In this paper we analyse the issues that have a significant impact on the mis match of the initial reservoir model with well logs and inverted 3 D seismic data. These issues include the constraining methods for reservoir lithofacies modelling, the sensitivity of the results to the presence of realistic resolution and noise in the seismic data, the geostatistical modelling parameters, and the uncertainties associated with quantitative incorporation of inverted seismic data in reservoir lithofacies modelling.
We demonstrate that in a geostatistical lithofacies simulation process, seismic constraining methods based on seismic litho-probability curves and seismic litho-probability cubes yield the best match to the reference model, even when realistic resolution and noise is included in the dataset. In addition, our analyses show that quantitative incorporation of inverted 3 D seismic data in static reservoir modelling carries a range of uncertainties and should be cautiously applied in order to minimise the risk of misinterpretation.
These uncertainties are due to the limited vertical resolution of the seismic data compared to the scale of the geological heterogeneities, the fundamental instability of the inverse problem, and the non-unique elastic properties of different lithofacies types.
Vermeesch, P. In a 3 D onshore-offshore controlled-source seismic experiment was carried out in an area of km x km, centered on the southern termination of the great Sumatra-Andaman earthquake rupture.
Root Mean Square traveltime misfit reduces from ms in the 1 D starting model to 81 ms after 20 non-linear iterations. Offsets range between 0 and km, with rays penetrating up to 28 km depth in the final model, hereby imaging the top of the subducting oceanic plate and revealing its complex 3 D topography. Ray coverage is still being extended by including first-arrival traveltime picks from the landstations on the coast of Sumatra and the islands and from the 10 long-term deployment OBSs that will be recovered in January.
The robustness and resolution of the final 3 D model is examined by exploring different starting models, different inversion parameters and by carrying out checkerboard tests and synthetic tests. The resulting crustal 3 D velocity model will allow us to explore the nature and physical cause of the rupture barrier of the great earthquake. Comparison with a similar dataset and subsequent 3 D velocity model acquired at the boundary between the and earthquakes will provide important insights into the segmentation of the Sumatra subduction zone and the dynamics of its great earthquakes.
Zelt, C. Barton Three-dimensional seismic refraction tomography: A comparison of two methods applied to data from the. We propose a 2 D seismic time-lapse inversion approach to image the evolution of seismic velocities over time and space.
The forward modeling is based on solving the eikonal equation using a second-order fast marching method. The wave-paths are represented by Fresnel volumes rathe Seismic source inversion using Green's reciprocity and a 3 - D structural model for the Japanese Islands. We present a feasibility study for seismic source inversions using a 3 - D velocity model for the Japanese Islands.
The approach involves numerically calculating 3 - D Green's tensors, which is made efficient by exploiting Green's reciprocity. The rationale for 3 - D seismic source inversion has several aspects. For structurally complex regions, such as the Japan area, it is necessary to account for 3 - D Earth heterogeneities to prevent unknown structure polluting source solutions. In addition, earthquake source characterisation can serve as a means to delineate existing faults.
Source parameters obtained for more realistic Earth models can then facilitate improvements in seismic tomography and early warning systems, which are particularly important for seismically active areas, such as Japan. For this we used a regional 3 - D velocity model, recently obtained from full waveform inversion. The model includes attenuation and radial anisotropy and explains seismic waveform data for periods between 10 - 80 s generally well.
The aim is to perform source inversions using the database of 3 - D Green's tensors. As preliminary steps, we present initial concepts to address issues that are at the basis of our approach. We first investigate to which extent Green's reciprocity works in a discrete domain. Considering substantial amounts of computed Green's tensors we address storage requirements and file formatting. We discuss the importance of the initial source model, as an intelligent choice can substantially reduce the search volume.
Possibilities to perform a Bayesian inversion and ways to move to finite source inversion are also explored. Is 3 D true non linear traveltime tomography reasonable? The data sets requiring 3 D analysis tools in the context of seismic exploration both onshore and offshore experiments or natural seismicity micro seismicity surveys or post event measurements are more and more numerous. Classical linearized tomographies and also earthquake localisation codes need an accurate 3 D background velocity model.
However, if the medium is complex and a priori information not available, a 1 D analysis is not able to provide an adequate background velocity image. Moreover, the design of the acquisition layouts is often intrinsically 3 D and renders difficult even 2 D approaches, especially in natural seismicity cases.
Thus, the solution relies on the use of a 3 D true non linear approach, which allows to explore the model space and to identify an optimal velocity image. The problem becomes then practical and its feasibility depends on the available computing resources memory and time.
In this presentation, we show that facing a 3 D traveltime tomography problem with an extensive non-linear approach combining fast travel time estimators based on level set methods and optimisation techniques such as multiscale strategy is feasible. Moreover, because management of inhomogeneous inversion parameters is more friendly in a non linear approach, we describe how to perform a jointly non-linear inversion for the seismic velocities and the sources locations.
Characteristics of spondylotic myelopathy on 3 D driven-equilibrium fast spin echo and 2 D fast spin echo magnetic resonance imaging: a retrospective cross-sectional study.
In patients with spinal stenosis, magnetic resonance imaging of the cervical spine can be improved by using 3 D driven-equilibrium fast spin echo sequences to provide a high-resolution assessment of osseous and ligamentous structures.
However, it is not yet clear whether 3 D driven-equilibrium fast spin echo sequences adequately evaluate the spinal cord itself. As a result, they are generally supplemented by additional 2 D fast spin echo sequences, adding time to the examination and potential discomfort to the patient.
Here we investigate the hypothesis that in patients with spinal stenosis and spondylotic myelopathy, 3 D driven-equilibrium fast spin echo sequences can characterize cord lesions equally well as 2 D fast spin echo sequences.
We performed a retrospective analysis of 30 adult patients with spondylotic myelopathy who had been examined with both 3 D driven-equilibrium fast spin echo sequences and 2 D fast spin echo sequences at the same scanning session.
The two sequences were inspected separately for each patient, and visible cord lesions were manually traced. We found no significant differences between 3 D driven-equilibrium fast spin echo and 2 D fast spin echo sequences in the mean number, mean area, or mean transverse dimensions of spondylotic cord lesions.
Nevertheless, the mean contrast-to-noise ratio of cord lesions was decreased on 3 D driven-equilibrium fast spin echo sequences compared to 2 D fast spin echo sequences. These findings suggest that 3 D driven-equilibrium fast spin echo sequences do not need supplemental 2 D fast spin echo sequences for the diagnosis of spondylotic myelopathy, but they may be less well suited for quantitative signal measurements in the spinal cord.
Structural and stratigraphic interpretation of 3 D seismic data for reservoir characterization in an area affected by dense faulting, such as the Niger Delta, is typically difficult and strongly model driven because of problems with imaging. In the Freeman field, located about km offshore southwestern Niger Delta at about m water depth, 3 D seismic attribute-based analogs, and structural and stratigraphic based geometric models are combined to help enhance and constrain the interpretation.
The objectives being to show how 3 D seismic attribute analysis enhances seismic interpretation, develop structural style and stratigraphic architecture models and identify trap mechanisms in the study area; with the main purpose of producing structural and stratigraphic framework analogs to aid exploration and production companies, as well as researchers in better understanding the structural style, stratigraphic framework and trap mechanism of the Miocene to Pliocene Agbada Formation reservoirs in the deep Offshore Niger Delta Basin.
A multidisciplinary approach which involved analyses of calculated variance-based coherence cube, spectral decomposition box probe and root-mean-square amplitude attributes, sequence stratigraphy based well correlation, and structural modeling; were undertaken to achieve these objectives.
Studies reveal a massive northwest-southeast trending shale cored detachment fold anticline, with associated normal faults; interpreted to have been folded and faulted by localized compression resulting from a combination of differential loading on the deep-seated overpressured-ductile-undercompacted-marine Akata shale, and gravitational collapse of the Niger delta continental slope due to influx of sediments.
Crestal extension resulting from this localized compression, is believed to have given rise to the synthetic, antithetic and newly observed crossing conjugate normal faults in the study area. This structure is unique to the existing types of principal. Reducing disk storage of full- 3 D seismic waveform tomography F 3 DT through lossy online compression. Full- 3 D seismic waveform tomography F 3 DT is the latest seismic tomography technique that can assimilate broadband, multi-component seismic waveform observations into high-resolution 3 D subsurface seismic structure models.
The strain tensor fields are needed for computing the data sensitivity kernels, which are used for constructing the Jacobian matrix in the Gauss-Newton optimization algorithm. In this study, we have successfully integrated a lossy compression algorithm into our F 3 DT-SI workflow to significantly reduce the disk space for storing the strain tensor fields. The compressor supports a user-specified tolerance for bounding the error, and can be integrated into our finite-difference wave-propagation simulation code used for computing the strain fields.
The decompressor can be integrated into the kernel calculation code that reads the strain fields from the disk and compute the data sensitivity kernels. During the wave-propagation simulations, we compress the strain fields before writing them to the disk. To compute the data sensitivity kernels, we read the compressed strain fields from the disk and decompress them before using them in kernel calculations. The integration of the lossy online compressor may potentially open up the possibilities of the wide adoption of F 3 DT-SI in routine seismic tomography practices in the near future.
In this study, we have successfully integrated a lossy compression algorithmmore » into our F 3 DT SI workflow to significantly reduce the disk space for storing the strain tensor fields. Environmental considerations for 3 D seismic in Louisianna wetlands. Louisiana swamps have been host to seismic crews for many years.
Results from recent 3 D surveys indicate that well planned and executed seismic operations have a minimal and short term impact in these environmentally sensitive wetlands. Pre-planning identifies challenges that require use of improved technology and work procedures. These include multi-channel radio telemetry recording systems, ramming of dynamite and hydrophones as opposed to drilling, DGPS positioning and coordinated use of Airboats, buggies and helicopters.
In addition to minimal environmental impact, increased data quality, reduced cost and shorter project duration have been achieved as a result of these efforts. Unlike 2Dmore » surveys, where profile positioning is flexible, 3 D surveys involve high density coverage over many square miles operated by numerous personnel. Survey design includes minimizing repeated traffic and crossing points.
Survey operations require environmental participation and commitment from every person involved in the project. This includes a thorough orientation and training program with strong emphasis on environmental sensitivity and awareness. Close co-ordination between regulatory agencies, clients and the contractor is a key factor in all aspects of the survey planning and operation. Benefits from these efforts are significant, measurable and continue to improve. Local seismic hazard assessment in explosive volcanic settings by 3 D numerical analyses.
This work deals with the assessment of local seismic response in the explosive volcanic settings by reconstructing the subsoil model of the Stracciacappa maar Sabatini Volcanic District, central Italy , whose pyroclastic succession records eruptive phases ended about 0. Heterogeneous characteristics of the Stracciacappa maar stratification, structural setting, lithotypes, and thickness variation of depositional units make it an ideal case history for understanding mechanisms and processes leading to modifications of amplitude-frequency-duration of seismic waves generated at earthquake sources and propagating through volcanic settings.
New geological map and cross sections, constrained with recently acquired geotechnical and geophysical data, illustrate the complex geometric relationships among different depositional units forming the maar. A composite interfingering between internal lacustrine sediments and epiclastic debris, sourced from the rim, fills the crater floor; a 45 meters thick continuous coring borehole was drilled in the maar with sampling of undisturbed samples.
Electrical Resistivity Tomography surveys and 2 D passive seismic arrays were also carried out for constraining the geological model and the velocity profile of the S-waves, respectively.
Single station noise measurements were collected in order to define natural amplification frequencies. Finally, the nonlinear cyclic soil behaviour was investigated through simple shear tests on the undisturbed samples.
Moreover, 1 D and 2 D numerical analyses were carried out for comparison purposes. Two different scenarios were selected as input motions: a moderate magnitude volcanic event and a high magnitude tectonic event. Both earthquake scenarios revealed significant ground motion amplification up to 15 in terms of spectral acceleration.
Kevitsa is a large disseminated sulphide Ni-Cu-PGE deposit hosted by the Kevitsa mafic-ultramafic intrusion in northern Finland and dated as about 2.
The Geological Survey of Finland first discovered the Kevitsa deposit in The final pit depth is planned to be m. The estimated ore reserves of the Kevitsa intrusion are about million tones using a nickel cut-off grade of 0. The expected life-of-mine is years. More than hundred holes have been drilled in the Kevitsa area, but most are concentrated close to the known deposit and do not provide a comprehensive understanding of the extent of the intrusion.
The basal contact of the intrusion is penetrated by only about 30 drill holes, most of which are shallow. A better knowledge of the geometry of the intrusion would provide a framework for near-mine and deep exploration in the area.
An exact knowledge on the basal contact of the intrusion would also provide an exploration target for the contact-type mineralization that is often more massive and richer in Ni-Cu. In December , a series of 2 D reflection seismic profiles was acquired in the Kevitsa area.
It consisted of four connected survey lines between 6 and 11 km long. The 3 D seismic survey is limited to the closer vicinity of the known deposit, while the 2 D seismic survey was designed to provide a more regional view of the Kevitsa intrusive complex. The main aims of the 2 D and 3 D seismic surveys were to delineate the shape and extent of the ore-bearing Kevitsa intrusion and the geometry of some of the host rock and surrounding units, and extract information about the larger-scale structures and structures important for mine-planning purposes.
The 2 D and 3 D seismic data were used to. SWTR is a new facility constructed specifically for the development and testing of futuristic intelligent battlefield sensor networks. In this paper, results are presented for an extensive high-resolution geophysical characterization study at the SWTR site along with validation using 3 - D modeling. In this study, several shallow seismic methods and novel processing techniques were used to generate a 3 - D grid of earth seismic properties, including compressional P and shear S body-wave speeds Vp and Vs , and their associated body-wave attenuation parameters Qp, and Qs.
These experiments covered a volume of earth measuring m by m by 25 m deep 11 million cubic meters , centered on the vehicle test track at the SWTR site. The study has resulted in detailed characterizations of key geophysical properties. To our knowledge, results of this kind have not been previously achieved, nor have the innovative methods developed for this effort been reported elsewhere. In addition to supporting materiel developers with important geophysical information at this test range, the data from this study will be used to validate sophisticated 3 - D seismic signature models for moving vehicles.
Plesa, A. The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport mission, to be launched in , will perform a comprehensive geophysical investigation of Mars in situ. The Seismic Experiment for Interior Structure package aims to detect global and regional seismic events and in turn offer constraints on core size, crustal thickness, and core, mantle, and crustal composition.
In this study, we estimate the present-day amount and distribution of seismicity using 3 - D numerical thermal evolution models of Mars, taking into account contributions from convective stresses as well as from stresses associated with cooling and planetary contraction.
Defining the seismogenic lithosphere by an isotherm and assuming two end-member cases of K and the K, we determine the seismogenic lithosphere thickness. Assuming a seismic efficiency between 0.
Interest in high-resolution 3 D seismic experiments for imaging shallow targets has increased over the past years. Many case studies presented, show that producing clear seismic images with this non-evasive method, is still a challenge. We use two test-sites where nearby outcrops are present so that an accurate geological model can be built and the seismic result validated.
The first so-called natural field laboratory is located in Boulonnais N. It is an upper Jurassic siliciclastic sequence; age equivalent of the source rock of N. The second one is located in Cap Blanc,to the southwest of the Mallorca island Spain ; depicting an excellent example of Miocene prograding reef platform Llucmajor Platform ; it is a textbook analog for carbonate reservoirs. In both cases, the multidisciplinary experiment included the use of multicomponent and quasi- or 3 D seismic recordings.
The target depth does not exceed m. Vertical and shear portable vibrators were used as source. In the center of the setups, boreholes were drilled and Vertical Seismic Profiles were shot, along with core and borehole measurements both in situ and in the laboratory. These two geologically different sites, with different seismic stratigraphy have provided us with exceptionally high resolution seismic images.
In general seismic data was processed more or less following standard procedures, a few innovative techniques on the Mallorca data, as rotation of horizontal components, 3 D F-K filter and addition of parallel profiles, have improved the seismic image.
In this paper we discuss the basic differences as seen on the seismic sections. The Boulonnais data present highly continuous reflection patterns of extremenly high resolution. This facilitated a high resolution stratigraphic description. Results from the VSP showed substantial wave energy attenuation.
However, the high-fold traces Mallorca seismic experiment returned a rather discontinuous pattern of possible reflectors. Method for identifying subsurface fluid migration and drainage pathways in and among oil and gas reservoirs using 3 - D and 4- D seismic imaging. The invention utilizes 3 - D and 4- D seismic surveys as a means of deriving information useful in petroleum exploration and reservoir management. The methods use both single seismic surveys 3 - D and multiple seismic surveys separated in time 4- D of a region of interest to determine large scale migration pathways within sedimentary basins, and fine scale drainage structure and oil-water-gas regions within individual petroleum producing reservoirs.
Such structure is identified using pattern recognition tools which define the regions of interest. The 4- D seismic data sets may be used for data completion for large scale structure where time intervals between surveys do not allow for dynamic evolution. The 4- D seismic data sets also may be used to find variations over time of small scale structure within individual reservoirs which may be used to identify petroleum drainage pathways, oil-water-gas regions and, hence, attractive drilling targets.
After spatial orientation, and amplitude and frequency matching of the multiple seismic data sets, High Amplitude Event HAE regions consistent with the presence of petroleum are identified using seismic attribute analysis. High Amplitude Regions are grown and interconnected to establish plumbing networks on the large scale and reservoir structure on the small scale.
Small scale variations over time between seismic surveys within individual reservoirs are identified and used to identify drainage patterns and bypassed petroleum to be recovered. The location of such drainage patterns and bypassed petroleum may be used to site wells. Overview of fast algorithm in 3 D dynamic holographic display. However, huge 3 D information and data should be preceded and be computed in real time for generating the hologram in 3 D dynamic holographic display, and it is a challenge even for the most advanced computer.
Many fast algorithms are proposed for speeding the calculation and reducing the memory usage, such as:look-up table LUT , compressed look-up table C-LUT , split look-up table S-LUT , and novel look-up table N-LUT based on the point-based method, and full analytical polygon-based methods, one-step polygon-based method based on the polygon-based method.
In this presentation, we overview various fast algorithms based on the point-based method and the polygon-based method, and focus on the fast algorithm with low memory usage, the C-LUT, and one-step polygon-based method by the 2 D Fourier analysis of the 3 D affine transformation. The numerical simulations and the optical experiments are presented, and several other algorithms are compared. The results show that the C-LUT algorithm and the one-step polygon-based method are efficient methods for saving calculation time.
It is believed that those methods could be used in the real-time 3 D holographic display in future. De-absorption pre-stack time migration QPSTM compensates for the absorption and dispersion of seismic waves by introducing an effective Q parameter, thereby making it an effective tool for 3 D , high-resolution imaging of seismic data. Although the optimal aperture obtained via stationary-phase migration reduces the computational cost of 3 D QPSTM and yields 3 D stationary-phase QPSTM, the associated computational efficiency is still the main problem in the processing of 3 D , high-resolution images for real large-scale seismic data.
In the current paper, we proposed a division method for large-scale, 3 D seismic data to optimize the performance of stationary-phase QPSTM on clusters of graphics processing units GPU. Then, we designed an imaging point parallel strategy to achieve an optimal parallel computing performance. Moreover, several key optimization strategies of computation and storage based on the compute unified device architecture CUDA were adopted to accelerate the 3 D stationary-phase QPSTM algorithm.
Compared with the initial GPU code, the implementation of the key optimization steps, including thread optimization, shared memory optimization, register optimization and special function units SFU , greatly improved the efficiency.
The presence of a gas hydrate petroleum system and seismic attributes derived from 3 D seismic data are used for the identification and characterization of gas hydrate deposits in the deepwater eastern Gulf of Mexico. In the central deepwater Gulf of Mexico GoM , logging while drilling LWD data provided insight to the amplitude response of gas hydrate saturation in sands, which could be used to characterize complex gas hydrate deposits in other sandy deposits.
In this study, a large 3 D seismic data set from equivalent and distal Plio-Pleistocene sandy channel deposits in the deepwater eastern Gulf of Mexico is screened formore » direct hydrocarbon indicators for gas hydrate saturated sands.
Transition zone structure beneath Ethiopia from 3 - D fast marching pseudo-migration stacking. Several models for the origin of the Afar hotspot have been put forth over the last decade, but much ambiguity remains as to whether the hotspot tectonism found there is due to a shallow or deeply seated feature.
Additionally, there has been much debate as to whether the hotspot owes its existence to a 'classic' mantle plume feature or if it is part of the African Superplume complex. To further understand the origin of the hotspot, we employ a new receiver function stacking method that incorporates a fast -marching three- dimensional ray tracing algorithm to improve upon existing studies of the mantle transition zone structure.
Using teleseismic data from the Ethiopia Broadband Seismic Experiment and the EAGLE Ethiopia Afar Grand Lithospheric Experiment experiment, we stack receiver functions using a three-dimensional pseudo- migration technique to examine topography on the and km discontinuities. Previous methods of receiver function pseudo-migration incorporated ray tracing methods that were not able to ray trace through highly complicated 3 - D structure, or the ray tracing techniques only produced 3 - D time perturbations associated 1- D rays in a 3 - D velocity medium.
These previous techniques yielded confusing and incomplete results for when applied to the exceedingly complicated mantle structure beneath Ethiopia. Indeed, comparisons of the 1- D versus 3 - D ray tracing techniques show that the 1- D technique mislocated structure laterally in the mantle by over km. Preliminary results using our new technique show a shallower then average km discontinuity and a deeper than average km discontinuity over much of the region, suggested that the hotspot has a deep seated origin.
Method for inverting reflection trace data from 3 - D and 4- D seismic surveys and identifying subsurface fluid and pathways in and among hydrocarbon reservoirs based on impedance models. A method is disclosed for inverting 3 - D seismic reflection data obtained from seismic surveys to derive impedance models for a subsurface region, and for inversion of multiple 3 - D seismic surveys i.
The method allows for the mapping and quantification of available hydrocarbons within a reservoir and is thus useful for hydrocarbon prospecting and reservoir management. The impedance values can be region grown to better isolate the low impedance hydrocarbon bearing regions. Impedance data derived from multiple 3 - D seismic surveys of the same volume can be compared to identify regions of dynamic evolution and bypassed pay.
Effective Oil Saturation or net oil thickness can also be derived from the impedance data and used for quantitative assessment of prospective drilling targets and reservoir management. Gas hydrate characterization from a 3 D seismic dataset in the deepwater eastern Gulf of Mexico. Principal component analysis of spectral decomposition results combined with amplitude and frequency seismic attributes derived from 3 D seismic data are used for the identification and characterization of gas hydrate deposits in the deepwater eastern Gulf of Mexico.
In this study, a large 3 D seismic data set from equivalent and distal Plio Pleistocene sandy channel deposits in the deepwater eastern Gulf ofmore » Mexico is screened for direct hydrocarbon indicators for gas hydrate saturated sands. Distribution of free gas and 3 D mirror image structures beneath Sevastopol mud volcano, Black sea, from 3 D high resolution wide-angle seismic data.
This study concentrates on a 3 D high resolution seismic grid 7 km x 2. The seismic profiles are typically longer than 6 km which results in large offsets for the reflections of the OBS.
This enables the study of the seismic velocities of the sub-seafloor sediments and additionally large offset incident analysis. The 3 D Kirchhoff mirror image time migration, applied to all OBS sections including all shots from all profiles, leads to a spatial image of the sub-seafloor. Here, the migration was applied with the velocity distribution of 1.
Acoustic blanking occurs beneath the south-easterly located OBS and is associated with the feeder channel of the mud volcano. There, gas from depth can vertically migrate to the seafloor and on its way to the surface horizontally distribute patchily within sediment layers. High amplitude reflections are not observed as continuous reflections, but in a patchy distribution. They are associated with accumulations of gas. Also structures exist within the feeder channel of the SMV.
Multi-azimuth MAZ 3 D seismic exploration is one of the most advanced seismic survey methods to improve illumination and multiple attenuation for better image of the subsurface structures. These two datasets were processed through the same processing workflow prior to velocity analysis and merged to one MAZ dataset. We performed velocity analysis on the MAZ dataset as well as two phases data individually and then stacked these three datasets separately.
We were able to pick more accurate velocities in the MAZ dataset compare to phase 1 and 2 data while velocity picking. Consequently, the MAZ seismic volume provide us better resolution and improved images since different shooting directions illuminate different parts of the structures and stratigraphic features.
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