ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1981.tb00701.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractFor years, reflection coefficients have been the main aim of traditional deconvolution methods for their significant informational content.A method to estimate seismic reflection coefficients has been derived by searching for their amplitude and their time positions without any other limitating assumption. The input data have to satisfy certain quality constraints like amplitude and almost zero phase noise—ghosts, reverberations, long period multiples, and diffracted waves should be rejected by traditional processing. The proposed algorithm minimizes a functional of the difference between the spectra of trace and reflectivity in the frequency domain. The estimation of reflection coefficients together with the consistent “wavelet’ is reached iteratively with a multidimensional Newton‐Raphson technique. The residual error trace shows the behavior of the process. Several advantages are then obtainable from these reflection coefficients, like conversion to interval velocities with an optimum calibration either to the well logs or to the velocity analysis curves. The procedure can be applied for detailed stratigraphic interpretations or to improve the resolution of a conventional velocity a

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1981.tb00702.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe determination of the nature of reservoirs containing hydrocarbons is approached via a pattern‐recognition method with prior learning. This method consists of comparing the nature of a reservoir that has been drilled into with an unknown reservoir. The known reservoir plays the part of a monitor for the learning process. To this end an algorithm is compiled using the Burg method of the features represented by different portions of traces contained in the reservoirs. An analysis of the dots representing these different features serves as a criterion for deciding whether the two reservoirs have identical or different nature

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1981.tb00703.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractOptimum multichannel filters can be designed to process seismic events falling on hyperbolic moveout curves using the conventional least‐squares method. Contrary to the linear moveout filters, autocorrelation and crosscorrelation functions inherent in the normal equations have to be computed numerically. However, computation times of filter coefficients are comparable to linear moveout operators.For a given source‐receiver geometry and assuming straight ray‐path, relative moveout of a seismic reflection event is dependent on the two way arrival time and rms velocity. Consequently, to avoid overlapping of pass and reject moveout windows, hyperbolic moveout filters have to be designed over time gates rather than for the whole record lengths. Hyperbolic and hyperbolic‐linear moveout filters applied to synthetic and field seismic reflection traces show good signal‐to‐noise (S/N) ratio improvements. Results of some combined synthetic and field data examples ar

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1981.tb00704.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractLarge gravity platforms are often used as alternatives to the more conventional pilesupported structures in hydrocarbon exploitation. A gravity structure, as opposed to the piled structure, is sitting on the sea floor by virtue of its weight and base width; as such it poses considerable problems for the site investigation engineer. One such problem is the calculation of the settlement of the structure and its time history; these depend upon the permeability and compressibility of the soil and its drainage conditions. The required data are usually obtained by sampling for subsequent laboratory testing. The collection of an undisturbed sample is beset by problems so that the consolidation behavior of the foundation material can only be inadequately assessed by laboratory testing. However, a series of laboratory consolidation experiments during which seismic velocities have been measured on the sample as consolidation proceeds shows that it is possible to reconstruct the stress‐strain and time‐dependent curves from the seismic data, once the initial void ratio and permeability of the soil are known. This leads the way to anin situtechnique for predicting settlement using a combination of geophysical techniques (electrical resistivity and seismic velocities) to obtain the required engineering propert

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1981.tb00705.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe design of a standard hydrophone with a maximally flat (Butterworth) response in the frequency range 8.0 Hz‐1.0 kHz is described. The standard hydrophone has been developed primarily for calibrating line hydrophone arrays (seismic streamers) and marine seismic sources.The standard hydrophone has been used successfully during the past eight years for monitoring the output of a single air gun. It can be used for the calibration of a marine seismic streame

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1981.tb00706.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThis tutorial paper presents a time‐domain derivation of the Normal equations which are associated with the normal‐incidence inverse problem. Connections are made between our time‐domain derivation and the more familiarz‐transform transfer function der

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1981.tb00707.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractA simple theory is presented to derive explicit recursive migration schemes in three dimensions which are suitable for situations with lateral velocity variations. The proposed schemes can be realized by one‐dimensional convolutions along thex‐axis andy‐axis. An investigation is made on the errors of each scheme. For each frequency component the amplitude error and the phase error are computed as a function of the immergence angle (dip). Based on the error analysis a critical discussion is given on the stability of explicit sc

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1981.tb00708.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

ResumeLes différentes sources d'erreurs de la mesure gravimétrique sont examinées. Leur connaissance a une importance particulière dans les prospections de surface, dites “microgravimétriques”.Les auteurs démontrent, expériences à l'appui, que toutes précautions prises, la source la plus fréquente d'erreurs de mesure en microgravimétrie est une mauvaise estimation de la dérive.Les auteurs exposent alors un processus de mesure et d'interprétation dont le but est une meilleure estimation de la dérive. La justification théorique et expérimentale du processus est donnée. La méthode implique une prise de mesure suivant une répartition spatiale aléatoire ou semi‐aléatoi

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1981.tb00709.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractA method has been developed for computation of the electrical DC potential of an arbitrary three‐dimensional resistivity structure using a finite difference method. The threedimensionality is necessary for interpretation of geoelectrical soundings with controlled point sources over a laterally inhomogeneous medium. Lateral inhomogeneities should be considered in resistivity soundings with large layouts. The results obtained with the described method permit a more realistic representation of geological features.The resolution of the method is determined by the number of elements in the resistivity network. The problem of core memory space has been resolved by using random access disc files. The results computed using a Fortranprogram are in good agreement with analytically obtained solution

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1981.tb00710.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY