Download or read book A Comparison of Seismic Processing Techniques on High resolution Multi channel Data in Deep and Shallow Water Conditions in the Solent U K written by Mark Edward Hewton Purtle and published by . This book was released on 2019 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Comparison of High resolution Seismic Methods for Determining Seabed Velocities in Shallow Water written by Thomas M. Brocher and published by . This book was released on 1985 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Comparison of Shallow Seismic Data Processing Using the Common Midpoint Stack and Plane Wave Synthesis at Hollywood Quarry Arkansas written by Nicholas Mason Prudot Gregg and published by . This book was released on 2006 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Processing of Multichannel Seismic Data from Shallow water Areas of Solomon Islands and Vanuatu written by Susan Cook and published by . This book was released on 1993 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Determination of the Most Efficient Processing Workflow to Enhance the Interpretability of Shallow Water 2D Marine Seismic Sections with and Without Shallow Gas in the Solent UK written by Sebastian D. Rosales Starchevich and published by . This book was released on 2019 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Processing of Multichannel Seismic Data from Shallow water Areas of Solomon Islands and Vanuatu written by W. Barclay and published by . This book was released on 1993 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Multi Component Seismic Data in the Shallow Water Environment of the Arabian Gulf written by Zhao Zhang and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The quality of the seismic data is essential to quantitative reservoir characterization of rock properties and geological structure interpretation. Although marine multi-component seismic data hold a wealth of information about both compressional and shear velocities, the acquisition suffers from high levels of noise, which make the processing a challenging task and drastically decreases optimal value extraction. This dissertation employs a four component (4C) processing workflow via advanced time-frequency-wavenumber filtering and polarization methods to improve data quality for further interpretation and reservoir characterization. The proposed workflow is used to enhance seismic reflected energy and explore the shear wave information in the horizontal components. This study makes use of one 2D seismic line and well log dataset from one offshore in the southern Arabian Gulf (Abu Dhabi, United Arab Emirates). A combination of strong lateral seafloor heterogeneities, shallow water depths (~10m), and hard sea bottom results in highly interfering and complex wave-fields and seemingly noisy seismic data acquired in this shallow water environment. Meanwhile, we expect converted wave modes (PS-S waves) due to the strong reflector at hard sea bottom. In this work, we first propose sophisticated filtering algorithms to attenuate surface waves, and then designed advanced processing sequence combined with existing techniques for converted waves detection. Compared to body waves, surface waves are characterized by low velocity, low frequency and high polarization. First, we utilize the variable factor S transform to transform the seismic data from time domain to time-frequency-wavenumber(TFK) domain. This designed transform provides better resolution control on both time and frequency by adjusting the shape of Gaussian window function through additional parameters. Second, we estimate the impacts of residual surface waves on rotation and suppress those waves using TFK dependent polarization analysis. Polarization attributes, ellipticity and rise angle, are calculated through a developed 3D covariance matrix analysis that exploits the joint relationship of wavenumber, time, frequency and polarization. Those computed attributes are used for attenuating the surface waves and determining radial and transverse components. Third, we introduce the new 4C ocean bottom cable (OBC) processing strategy using both compressional and shear waves to recover the image of the subsurface from noisy seismic data. Comparing the time slices and gathers before and after using the strategy, it is observed that the method, described here, attenuates surface waves and remnant surface waves effectively and improves the signal to noise ratio without weakening the desired reflected signals. The results from this dissertation will find application in reservoir characterization from shear wave and converted wave analysis. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155180
Download or read book High resolution Seismic Profiling written by Jan Brouwer and published by . This book was released on 1988 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Resolution Analysis of Shallow Seismic Data written by Jeffrey L. Hoffman and published by . This book was released on 1986 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Marine Survey System for Real time Multi channel Acquisition and Processing of High Resolution Seismic Profiler Data written by A. Settery and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reprocessing of High Resolution Beaufort Sea Seismic Data written by Petty-Ray Geophysical Inc and published by . This book was released on 1978 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Earlier this year line 76013 from the 1976 Kenting High Resolution survey was subjected to reassessment via reprocessing. Fairfield Industries, Digitech and Petty Ray were each presented with the same line and asked to reprocess the data. The most successful and least expensive reprocessing was done by Petty Ray in London, England. The success of the reprocessing together with drilling problems encountered in the top 2000 feet of section prompted further reprocessing to be carried out in lesser quality data areas. Petty Ray was chosen to reprocess lines 76020 (Nektoralik to Kopanoar tie line), 76021 (Kaglulik A-75), and line 22 from the 1977 Fairfield Sparker data through Kaglulik. Our centre at Geodigit reprocessed line 76005 (Nerlerk). A short discussion on the reprocessing of line 76005 has been presented separately [described by ASTIS record 42727]. Line 76020 runs from Nektoralik, intersecting with line 76013 where data quality is known to be good and through to Kopanoar where further well control is available. On the included section it has been possible to correlate a high amplitude event at 800 msec (2500 feet) with a series of gas-bearing sand layers. Also, at about 400 msecs (1300 feet), an event has been outlined coincident with base of permafrost. This is seen to disappear somewhere west of Kopanoar. The exact location of the disappearance is not clear but it may be in the vicinity of SP 1360 where an abrupt change is data quality can be seen. The change in data quality is, however, more likely to be a field problem rather than the limit of permafrost. The possibility, however, should not be discounted. Sonic Log/Seismic comparison has already been successful at Nektoralik. Comparison between 76020 and line D-28A shows that greater continuity and definition of events below 0.5 seconds could be achieved by expanding the conventional seismic data than has been achieved from the 1976 H.R. airgun survey. Some H.R. data from the 1978 survey is coincident with exploration lines and a similar comparison should be done to determine the value of the latest H.R. data. The reprocessing of line 76021 was less successful. Three layers have been indicated on the included section of correlation with known permafrost lenses at the well location. The validity and extrapolation of the layers, however, is rather dubious. An event is seen at 550 msecs coincident with a mudstone to sand and siltstone interface and associated water kick. A possible unconformity is indicated. The event, however, appears more continuous and better defined on line HRD-78-3, acquired and processed this year (not included in this discussion). Line K-22 is a sparker line through Kaglulik A-75, acquired during the 1977 site investigations. Severe energy penetration limitations are still the main problem although substantial improvement in the shallow data has been achieved by the reprocessing. In comparison to airgun line 76201, it is seen to be a much higher frequency section although reverberation and interbed multiples are proportionally higher. (Au)."--ASTIS online database.
Download or read book Improving Accuracy and Efficiency of Seismic Data Analysis Using Deep Learning written by Harpreet Kaur (Ph. D.) and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ultimate goal of seismic data analysis is to retrieve high-resolution information about the subsurface structures. It comprises different steps such as data processing, model building, wave propagation, and imaging, etc. Increasing the resolution and fidelity of the different seismic data analysis tasks eventually leads to an improved understanding of fine-scale structural features. Conventional implementation of these techniques is computationally intensive and expensive, especially with large data sets. Recent advances in neural networks have provided an ability to produce a reasonable result to computationally intensive and time-consuming problems. Deep neural networks are capable of extracting complex nonlinear relationships among variables and have shown efficacy as compared to conventional statistical methods in different areas. A major bottleneck for seismic data analysis is the tradeoff between resolution and efficiency. I address some of these challenges by implementing neural network based frameworks. First, I implement a neural network based workflow for stable and efficient wave extrapolation. Conventionally, it is implemented by finite differences (FD), which have a low computational cost but for larger time-steps may suffer from dispersion artifacts and instabilities. On the other hand, recursive integral time extrapolation (RITE) methods, especially the low-rank extrapolation, which are mixed-domain space-wavenumber operators are designed to make time extrapolation stable and dispersion free in heterogeneous media for large time steps, even beyond the Nyquist limit. They have high spectral accuracy; however, they are expensive as compared to finite-difference extrapolation. The proposed framework overcomes the numerical dispersion of finite-difference wave extrapolation for larger time steps and provides stable and efficient wave extrapolation results equivalent to low-rank wave extrapolation at a significantly reduced cost. Second, I address wave-mode separation and wave-vector decomposition problem to separate a full elastic wavefield into different wavefields corresponding to their respective wave mode. Conventionally, wave mode separation in heterogeneous anisotropic media is done by solving the Christoffel equation in all phase directions for a given set of stiffness-tensor coefficients at each spatial location of the medium, which is a computationally expensive process. I circumvent the need to solve the Christoffel equation at each spatial location by implementing a deep neural network based framework. The proposed approach has high accuracy and efficiency for decoupling the elastic waves, which has been demonstrated using different models of increasing complexity. Third, I propose a hyper-parameter optimization (HPO) workflow for a deep learning framework to simulate boundary conditions for acoustic and elastic wave propagation. The conventional low-order implementation of ABCs and PMLs is challenging for strong anisotropic media. In the tilted transverse isotropic (TTI) case, instabilities may appear in layers with PMLs owing to exponentially increasing modes, which eventually degrades the reverse time migration output. The proposed approach is stable and simulates the effect of higher-order absorbing boundary conditions in strongly anisotropic media, especially TTI media, thus having a great potential for application in reverse time migration. Fourth, I implement a coherent noise attenuation framework, especially for ground-roll noise attenuation using deep learning. Accounting for non-stationary properties of seismic data and associated ground-roll noise, I create training labels using local-time frequency transform (LTF) and regularized non-stationary regression (RNR). The proposed approach automates the ground-roll attenuation process without requiring any manual input in picking the parameters for each shot gather other than in the training data. Lastly, I address the limitation of the iterative methods with conventional implementation for true amplitude imaging. I implement a workflow to correct migration amplitudes by estimating the inverse Hessian operator weights using a neural network based framework. To incorporate non-stationarity in the framework, I condition the input migrated image with different conditioners like the velocity model and source illumination. To correct for the remnant artifacts in the deep neural network (DNN) output, I perform iterative least-squares migration using neural network output as an initial model. The network output is close to the true model and therefore, with fewer iterations, a true-amplitude image with the improved resolution is obtained. The proposed method is robust in areas with poor illumination and can easily be generalized to more-complex cases such as viscoacoustic, elastic, and others. The proposed frameworks are numerically stable with high accuracy and efficiency and are, therefore, desirable for different seismic data analysis tasks. I use synthetic and field data examples of varying complexities in both 2D and 3D to test the practical application and accuracy of the proposed approaches
Download or read book Full Seismic Waveform Modelling and Inversion written by Andreas Fichtner and published by Springer Science & Business Media. This book was released on 2010-11-16 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent progress in numerical methods and computer science allows us today to simulate the propagation of seismic waves through realistically heterogeneous Earth models with unprecedented accuracy. Full waveform tomography is a tomographic technique that takes advantage of numerical solutions of the elastic wave equation. The accuracy of the numerical solutions and the exploitation of complete waveform information result in tomographic images that are both more realistic and better resolved. This book develops and describes state of the art methodologies covering all aspects of full waveform tomography including methods for the numerical solution of the elastic wave equation, the adjoint method, the design of objective functionals and optimisation schemes. It provides a variety of case studies on all scales from local to global based on a large number of examples involving real data. It is a comprehensive reference on full waveform tomography for advanced students, researchers and professionals.
Download or read book Europe s Lost World written by Vincent L. Gaffney and published by Council for British Archaeology. This book was released on 2009 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: This excellent book, which deserves a wide readership, reports on the work of the North Sea Palaeolandscapes Project, which has been researching the fascinating lost landscape of Doggerland which until the end of the last Ice Age connected Britain to the continent in the North Sea area. It aims to make the findings available to a general readership, and show just how impressive they have been, with nearly 23,000km2 mapped. The techniques used to reconstruct the landscape are explained, and conclusions and speculation about the climate and vegetation of the area in the Mesolithic offered. It also tells the story of the rediscovery of Doggerland, and the Mesolithic landscape more generally, from the pioneering work of Clement Reid in the nineteenth century, to the research of Grahame Clark and Bryony Coles in the twentieth. It's also worth pointing out just how well produced and illustrated the book is, and one can only hope that it can spark public interest in a comparatively little known phase of our prehistory.
Download or read book Mapping Doggerland written by Vincent L. Gaffney and published by Archaeopress. This book was released on 2007 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mapping Doggerland documents the methodology and results of an innovative project to investigate a large area of the Southern North Sea, submerged during the last Glacial Maximum between 10,000 and 7500 bp.
Download or read book Encyclopedia of Coastal Science written by M. Schwartz and published by Springer Science & Business Media. This book was released on 2006-11-08 with total page 1243 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new Encyclopedia of Coastal Science stands as the latest authoritative source in the field of coastal studies, making it the standard reference work for specialists and the interested lay person. Unique in its interdisciplinary approach. This Encyclopedia features contributions by 245 well-known international specialists in their respective fields and is abundantly illustrated with line-drawings and photographs. Not only does this volume offer an extensive number of entries, it also includes various appendices, an illustrated glossary of coastal morphology and extensive bibliographic listings.
Download or read book Conference on Inverse Scattering Theory and Application written by J. Bee Bednar and published by SIAM. This book was released on 1983-01-01 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
