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53rd EAEG Meeting
- Conference date: 26 May 1991 - 30 May 1991
- Location: Florence, Italy
- ISBN: 978-90-73781-03-0
- Published: 28 May 1991
101 - 150 of 315 results
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Anisotropic tomography: Part I, Background
Authors F. Muir, R. Michelena and J. HarrisHydrocarbon reservoirs may often be found in rocks which have quite variable degrees of velocity anisotropy. For example, marine shales may be much more anisotropic than the porous sands associated with them. It follows that anisotropic inversion methods present opportunities for adding useful information, and for preventing image mispositioning due to an overly simplified velocity model.
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A complete waveform inversion
Authors S. C. Singh, M. Dietrich and F. ChapelSeismic waveform inversion consists of minimizing misfit between observed and calculated wavefields. Since this misfit function could be highly non-linear, the only way to be sure of arriving at the global solution is to use a Monte-Carlo search. This is feasible if the number of unknown parameters is not too large. If it is large, as is the case with the seismic inverse problems, it is extremely expensive to use the Monte-Carlo search to optimize for a single misfit function over the whole model space. However, if one uses a number of misfit functions depending up on the sensitivity of the model parameters on the data, one can implement the Monte-Carlo method efficiently. Fortunately, this is possible as the different wavelengths of the model parameters influence the different parts of the data.
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Nonlinear wave form inversion: Application to real data
Authors N. Roxix and A. TarantolaIn principle, nonlinear inversion that finds the distribution of elastic parameters in the Earth whose synthetic data best matches the observed data is an ideal inversion. All seismic wave phenomena such as reflected waves, mode-conversions, refracted waves, transmitted waves, Rayleigh waves etc. are used to obtain the inversion result.
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Petrophysical characterisation of the tertiary for seismic AVO investigations, UK Central North Sea
By J. M. ReillyThe investigation of the variation in seismic Amplitude Versus Offset (AVO) is an increasingly important geophysical technique in the exploration for, and exploitation of, hydrocarbon bearing reservoirs in the Eocene of the U.K. North Sea.
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Simulated annealing based 2-D inversion of reflection seismic data from a carbonate evaporite sequence
Authors J. M. Pedersen, P. D. Vestergaard, K. G. Maver and J. J. MøllerA recently developed inversion method based on a global model optimization method called simulated annealing has been applied to seismic reflection data from a carbonate evaporite sequence onshore in Denmark. The inversion resulted in detailed information about the acoustic impedance profile of a target zone.
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Null spaces in AVO inversion of single interfaces
Authors A. Mazzotti and G. DrufacaThe AVO Inversion and Interpretation are research topics of great interest since they may yield precious information on the elastic parameters of sub-surface targets. This paper is focused on the problem of AVO Inversion of reflections from a single interface. A real data example shows that, even in the simple case of single-interface reflections, a non-unique estimate of the unknown parameters results from a limited-offset data set. The real data are reflections from a low-velocity gas-sand embedded in shales at about 0.7 s traveltime. They produce a classic bright spot that clearly stands out in the stack section.
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Statistical analysis on AVO data
Authors F. Hindlet, Y. Z. Ma and A. G. HaasAmplitude versus offset (avo) interpretations involve a large volume of data. In order to carry out lithologic predictions, the avo data is reduced and simplified by various methods: avo gradients, zero offset amplitudes, even common mid point (cmp) stacks. All these displays are simplifications of a data set that may be influenced by several amplitude factors, such as lithology, tuning effects, correlated noise etc.
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Transformations of volume reflectivity into seismic classifiers
Authors L. Sonneland, O. Barkved, M. Olsen and J. -H. NittebergThe conventional description of the seismic reflection process is an interaction between the incident wavefield. the reflected and transmitted wavefield at a surface boundary. The surface-boundary is defined by the discontinuity surface of some elastic parameter. Dependent on the wavefield and the contrast in elastic parameters a reflection coefficient can be associated with this discontinuity surface. We will refer to this description of the reflection process as "surface reflectivity".
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Evaluation of the ambiguities of seismic inversion
More LessThe problem of acoustic and elastic inversion has been studied by several authors; however, there is still the need to understand completely the ambiguities of the inversion, i.e. to determine the reliability of the solution. The wavefield obtained insonifying the medium that results from the inversion will match the data, but there is no guarantee that the solution proposed is the realone. Besides, another interesting problem, not yet completely solved, is the determination of the resolution of velocity analyses, in presence of an unknown AVO.
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A study of the orientational variation of induced polarization time domain data
Authors F. E. R. Almeida and M. J. S. MatiasThe Induced Polarization Exploration Method has been used intensively in areas of complex geology. In such areas pronounced orientational effects have been observed in resistivity measurements. However the orientational behaviour of induced polarization data has been overlooked.
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Two-modal cole-cole modelling of lP time domain relaxations
Authors R. di Maio and D. PatellaThe dominant method for detecting and delineating native pyrite mineralization is Induced Polarization (lP). In presence of hydrocarbon reservoirs the lP anomalies are thought to he caused by epigenetic pyritization located in a plume over oil fields in a geochemically active environment. In geothermal areas the observed lP anomalies can be associated with pyrite concentrations deposited where sulfur-rich thermal waters interrnix with meteoric waters.
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Transformation of transient decays to continuous apparent resistivity curves, a generalized apparent resistivity definition
By L. SöresIn the interpretation of electromagnetic methods a very simple way of getting rid of the geometric and primary field effects is transforming measured data to apparent resistivities. The main principle for this transformation is generally to determine the resistivity of the substituting homogeneous halfspace.
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Sampo, a new wide-band electromagnetic system
Authors H. Soininen and T. JokinenThe SAMPO(Gefinex 400 S) wide-band electromagnetic (EM) system was designed and constructed during 1986-1988 by Outokumpu Electronics in cooperation with the Geological Survey of Finland.
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Application of an electromagnetic borehole induction logger to groundwater contamination mapping
Authors J. D. McNeill and M. BosnarAlthough electromagnetic induction loggers have been used by the oil industry for many years their sondes are generally unsuitable for groundwater applications, for which the requirements are 1 . Slim probes (monitoring Wells are often only 5 cm in diameter) 2 . Good vertical resolution, so as to resolve thin contaminant plumes, combined with a moderate radial depth of investigation (of the order of 1m) 3 . Low noise and good stability so as to measure background conductivities as low as 1 mS/m (1000 ohmm ) 4 . Linear response with conductivity to about 3000 mS/m (0 .3 ohmm ) 5 . Modest depth of exploration, seldom in excess of 250 m, and lastly 6 . The overall system (including winch and console) must be compact, lightweight and relatively inexpensive .
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Geoelectrical methods in geological mapping - Case histories from the Balaton Highland, Hungary
Authors I. Szilagyi, B. Csatho, G. Csillag and L. KoloszarVarious geoelectrical measurements have been widely used for bauxite and coal prospecting in the Hungarian Transdanubian Central Range for decades. These mountain form a syncline structure, bauxite deposits can be found in their central part in tectonically preformed karstic depressions of resistive Mesozoic -mainly Upper Triassic- carbonates. Conductive Cenozoic formations including coal beds cover the bauxite lenses and the basement. This resistivity contrast and the approximately 1-D model allow to determine the depth to the basement and to distinguish the main structural units in the study area using geoelectrical methods.
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Application of a surface-to-borehole frequency EM method for the detection of deep conductive orebodies: A test study in the Iberian Pyrite belt
Authors B. Bourgeois and J. BernardThrough recent advances in instrumentation, procedures and interpretation, borehole electromagnetic (EM) methods have become of great interest in the exploration of conductive orebodies lying at several hundreds of meters below the surface. In particular, when a borehole has missed a suspected mineralised target, these methods can indicate whether or not the expected conductive body does in fact exist in the vicinity of the borehole, and in certain cases, in which direction it lies. Consequently, these techniques are valuable for mining companies, as they can save a great deal of expensive drilling.
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Fixed source EM two-dimensional modelling using finite elements with quadrature base functions
By P. VallaAlthough 2-D modelling has been widely applied to the magnetotelluric method, few results have been published for frequency EM controlled source methods, besides the work of J. Doherty (1988) using surface integral equations. Because it allows to deal with more complex modeis, the finite element techniques (J.H. Coggon, 1971, L. Rijo, 1977) is the most popular, but its application to controlled source EM requires specific improvements of the algorithm, as shown in the following.
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Two dimensional forward seismic modelling: A case study of lithology prediction of the Zechstein interval, Southern Jylland, Denmark
By K. G. MaverFrom a number of wells and a closely spaced grid of seismic sections, it is possible by two dimensional forward seismic modelling, to predict the lithological framework below what is normally thought of as the seismic resolution limit. It is thus possible to build a geological model with sequence thicknesses of for instance 5 meters at a depth of 1600 meters. The modelling is executed by generation of a synthetic section imaging the seismic section and results in a geological model with a high degree of detail.
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An integrated approach to characterization of Pennsylvanian carbonates
Authors B. J. Rafison and G. A. LivesayA multi-disciplinary integration of seismic techniques was used in this work to characterize carbonate mounds in the Midland Basin. Conventional seismic data and computed seismic attributes were studied for four lines from a 3D seismic survey. The analyses were carried out in six phases (Figure 1): I) Pre-stack AVO Analysis; 2) Geological Analysis ; 3) Petrophysical Analysis; 4) Post-stack Attribute Analysis; 5) Seismic Lithologic/Stratigraphic Modeling ; and 6) Interpretation and documentation of the results.
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Integrated study of an unconsolidated reservoir
Authors J. P. Blangy and S. StrandenesThe following two objectives were sought in order to improve volumetric analyses and to enhance the production of a field from the North Sea: map the gas/oil contact, and its evolution through time as the field is produced, and identify areas of high permeability. By integrating petrophysical data such as empirically derived porosity-permeability relationships for each facies, an attempt is made at characterizing the seismic response of high permeability sands and to identify them seismically.
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Minor fault geometries and their effect on seismic data in the West African Salt Basin
Authors P. M. Trayner, G. G. Grant and D. StaughtonSeismic data recently acquired by GECO in the offshore West Africa Salt Basin image numerous minor faults in the post-Miocene section. The faults have normal throw and the majority dip shoreward, ie opposite to the present bathymetric slope. This direction is contrary to that which would be expected in a model of gradual downslope creep and their consistency on dip lines has led to the images being dismissed as spurious features introduced during data processing.
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Improved reservoir description by use of seismic amplitude maps at Veslefrikk Field, North Sea
Authors L. Pedersen, S. Befrin, E. Berg and E. HegreThe Veslefrikk field was declared commercial based on observations from only two exploratlon wells and a 3-D seismic survey. The field has been in production for one year now.
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Reservoir characterization: A case history of the Sarir Field, Sirte Basin, Lybia
Authors R. O. Lindseth and N. A. BerruienThe elevation of the oil/water contact within the massive Sarir field, located in the Sirte basin of Libya, is relatively uniform, suggesting continuous communication of the reservoir over the entire field. Yet, preliminary injectivity tests and drilling of peripheral injectors suggested otherwise. In some cases injection of water was found to he poor and distribution of fluid did not appear uniform. Also, the location of some peripheral injectors was well within the productive limit because the water/oil contact was poorly defined.
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An integrated approach to reservoir petrophysical parameters evaluation
Authors E. Poggiagliolmi and D. LowdenPetrophysical parameters necessary for reservoir characterisation are normally derived from borehole data. Such information can be very accurate in the depth direction but has a small lateral penetration. Surface seismic, on the other hand, has low vertical resolution but is laterally continuous. Calibration of the seismic data to borehole information through integrated processing permits reservoir petrophysical parameters to be accurately mapped from seismic data. The relationship between seismic and petrophysical properties is addressed with reference to a reservoir evaluation study. The relationships are used to calibrate seismic data and to map heterogeneities in reservoir description parameters.
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G.I. Gun sea trials
More LessThe search continues for the ideal marine seismic source. Each of the currently available sources has its good and bad points. Air guns suffer from long-period bubble oscillation, and so have to be used in large arrays. Water guns have good short signatures, but these are non minimum phase. A 'bubble-free' airgun would be a very attractive source, and the G.I Gun is an attempt to attain this (Pascouet 1989). This paper presents results from trials of the G.I. gun, and a comparison between G.I. guns and water guns.
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Modelling of G.I. Gun signatures
By M. LandrøTwo years ago A. Pascouet (1989) presented a new airgun called the GI gun. The main characteristic of this gun is its ability to control (i.e. damp) its own bubble oscillation. The removal of the bubble osciallion is achieved through a tuning of air injection within the bubble. In order to achieve optimal bubble suppression the amount of injected air must be of the order of two times the original amount of air used to create the primary pressure pulse (see Pascouet, 1989). It has been shown however (SSI-brochure), that even if the volume ratio between injected air and original air is reduced to 1.0 (i.e. the gun is operated in the harmonic mode), farfield signatures with a very good primary to bubble ratio can be achieved.
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The low frequency response of high resolution airgun arrays
Authors D. J. Painter, R. H. Seymour and P. J. SmithDuring the past ten years the development and deployment of sleeve airguns and water guns have significantly improved the high frequency content on the final seismic section with a consequent gain in resolution. A critical issue is to what extent the industry's quest for improved high frequency has resulted in loss of low frequency energy and a reduction in penetration. This paper uses a simple theoretical model to examine the compromises, and illustrates the conclusion using results from seismic surveys.
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Modelling air gun array performance specifications
Authors W. R. Cotton and D. J. MonkAir gun arrays have been the preferred source for hydrocarbon exploration for nearly 25 years. One of the challenges over that period has been the computer simulation of the array signatures. The acoustic signal from an array of many air guns is sufficiently complex to thwart many early attempts at accurate modelling. As a result, it was not possible to predict the performance of an array under deteriorating conditions of operation such as the failure of specific guns. operating specifications were deduced from sparse information obtained from far field signature recordings and they carried the risk of being conservatively described without being comprehensive in coverage.
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Comparison of airgun clusters
Authors S. Strandenes, S. Vaage, G. Zaalberg-Metselaar and A. SodalLast year, Vaage, Strandenes & Metselaar [1] reported results from measurements of several symmetrical two gun clusters with varying separation distance, depth, firing pressure and source type. The source-types involved were Bolt 600 C airguns with volumes 10, 20 and 40 cu. inch, Sleeve airguns with volumes 10, 40, 70 and 150 cu. inch and Bolt Combo airguns with volumes 10, 40 and 90 cu. inch. It was found that the optimal gun separation in asymmetrical two gun cluster, based on this database, was 2.4 times the equilibrium radius, that the improvement in primary/bubble ratio on the average was a factor of 2.4 times the ratio for two corresponding non interacting guns and that the loss in primary peak amplitude at the optimal distance was 15 %.
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Signature measurements concerning the exploitation of interaction in the design of compact airgun arrays
Authors Mo. H. Safar, V. B. Hewett and P. HaskeyIn a paper presented at the 37th EAEG Annual Meeting held in Bergen, June 1975, Safar proposed a method (UK Patent No. 1542261) for efficient design of compact airgun array. The proposed method (Safar, 1976) involves the damping of the bubble pressure pulses by exploiting the interaction between a number of properly spaeed identical airguns.
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A New marine vibrator based on Terfenol-D
Authors R. Fritsvold, B. Ursin-Holm and R. TenghamnThe Vibroseis technique was introduced to the geophysical industry in the early 1960'5 and has been used successfully in land seismic acquisition world-wide. In the early 1980'5, steps were taken to convert the technology from land to the marine environment. The Hydraulic based Marine Vibrators developed 50 far, are mainly constructed as large and complex mechanical systems that are intricate to operate from a vessel.
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Synthetic seismograms from extended ray tracing
Authors A. Hanyga and H. B. HelleIn [1,2,3] a method of numerical computation of wave fields is developed. It is an extension of Asymptotic Ray Theory (ART) applicable in regions containing caustics. The essential features of the new method. called Extended Ray Tracing (ERT), consist in application of expressions which are well-defined at caustics in combination with complex ray tracing in caustic shadows.
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Extrapolation operators by beam tracing
Authors S. R. G. Kremer, J. T. Fokkema and C. P. A. WapenaarThe key process in seismic imaging is given by migration. The accuracy and efficiency of the migration process is directly determined by the involved downward extrapolation operators. Taking into account that a downward extrapolation operator equals the response at the surface due to a point source in a subsurface grid point of a macro model, the computation of point source responses in macro models is of vital importance for the seismic method.
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2D Modelling of thin layers
Authors G. Bernasconi and G. DrufacaForward modelling of seismic response of thin layers is not perforrned satisfactorily by conventional techniques. Finite-Difference methods stumble upon small grids, Ray-Tracing becomes cumbersome with conversions, multiples and post critical effects, and Reflectivity works only with horizontal layers. Hybrid schemes that join ray methods with reflectivity might offer a useful low-cost alternative [1,2]. Our scheme uses rays to transport the reflectivity of thin-layered small-scale discontinuities across large scale homogeneities. Conversely transmissivity - that takes into account interbed reverberation and conversions - correctly energizes transmitted rays, even in post critical situations.
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Reflectivity revisited
Authors A. J. Berkhout, C. P. A. Wapenaar and C. G. Mde BruinThe seismic method is based on the fundamental property that downward travelIing seismic source wave fields are returned to the surface by reflection (and/or refraction). Hence the reflectivity property of the subsurface plays a key role in seismic exploration. Structural information is gene rally derived from 'average' reflectivity. Lithologic information can be derived as weIl, provided angle-dependent reflectivity is taken into account.
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Generalized born scattering and Quasi-Shear ray coupling in anisotropic media
Authors C. H. Chapman and R. T. CoatesThe propagation of high-frequency seismic waves through inhomogeneous media can often be described well by asymptotic ray theory. Nevertheless, situations in which ray theory breaks down are widespread and of interest: rays may be focused at caustics causing amplitude singularities; wavefronts may contain amplitude discontinuities causing diffracted signals, e.g. at critical points or shadows; signals may be scattered by inhomogeneities causing low-frequency reflections; and rays may couple due to rapid variations in the ray solutions. In this paper, we concentrate on extensions of ray theory that solve the last two problems - scattering and coupling between ray solutions due to inhomogeneities in the model and ray solution.
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Computation of ray-born synthetic seismograms for anisotropic, inhomogeneous media
Authors R. L. Gibson and M. N. ToksözScattering of seismic waves by inhomogeneity in the earth leads to significant effects on observations of seismic energy. We apply an algorithm similar to that proposed by Beydoun and Mendes (1989) to model these scattered wavefields by combining the Born approximation and ray theory. Scattered displacements generated by a perturbation to a known background earth model are described by the Born approximation, whereby the inhomogeneity is treated as a secondary source radlating energy as it interacts with the incident waves from the true source. Variations in density act as single force sources, while perturbations to any of the 21 independent elastic constants lead to moment tensor secondary sources.
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Seismic traveltime equations for Azimuthally Anisotropic and Isotropic media
By A. G. SenaThe interpretation of traveltime curves over layered anisotropic media would give more physical insight if analytical (although approximate) formulas for such traveltime curves in terms of the subsurface anisotropy were available. In this paper, we derive the analytical expressions for traveltime-offset curves over multilayered weakly azimuthally anisotropic and isotropic media in terms of the elastic properties of each layer. This method is based upon an approximate skewed hyperbolic moveout formula involving three measurement bulk velocities for each reflector: the average vertical velocity and horizontal and skew moveout velocities. This technique allows for fast traveltime computation and extremely rapid estimation of the interval elastic parameters.
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Electrical conductivity of the earth crust in Europe
By L. VanyanFar from relatively narrow conducting anomalies (graphite shist belts, fracture zones, etc.) the background electrical resistivity of the upper part of crystaline Earth crost reaches 105 -106 Ohm.m. It coincides with laboratory measurements if taken into account porosity value and water in pores. One could expect an increase of the resistivity with depth due to closing of pores. But unexpectedly resistivity is decreasing at dep th of 10-20 km practically for all investigated areas of Europe. Magnetotelluric soundings of the last decade showed that the conductivity value of the lower crost is similar to that of the sediment cover. This fact is in a sharp disagreement with high resistivity of the dry lower crost rocks derived from laboratory measurements.
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Integrated gravity, seismic and geological modelling in the Rhine Graben
More LessA combined geophysical and geological interpretation of the Rhine Graben and vicinity in SW Germany is presented in the form of three 2-D, 250km profiles, starting from the S edge of the Rhenish shield and adjacent Lorraine and Saar-Nahe basins, crossing the Rhine Graben in three separate sections, and extending across the Mesozoic platform to the fore-alpine Molasse Basin.
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2D and 3D seismic modelling of crustal structural heterogeneities
Authors S. Hestholm, B. O. Rosland, E. S. Husebye and B. O. RuudSeismic surveys are based on analysis of complex short wavelength signaIs, while the resolved model elements are often simple and of much longer wavelength. Furthermore, attribute analysis of three component seismic records testifies towarels medium complexities not commonly incorporated in the structural modeIs. To provide better understanding of high frequency wave propagation within the heterogeneous crust, we use finite difference (FD) modeling in 2D and 3D in combination with more conventional analysis of seismological data.
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Shear-waves from 3-C ocean bottom seismographs indicative of anisotropy in the lower crust
Authors R. Mjelde, M. A. Sellevoll and E. W. BergThis refraction study was performed in August 1988 by the Institute of Solid Earth Physics, University of Bergen, Norway in cooperation with the Hokkaido and Tokyo Universities, Japan. The purpose of the experiment was to map the crustal structure off Lofoten, northern Norway, from the outer part of the continental shelf to the oceanic crust, and to make use of all three components of the Ocean Bottom Seismographs (OBS) in a detailed shear-wave study. Twenty one 3-C OBSs were used along 8 profiles in a 3D grid.
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Amplitude and time-frequency analysis of ecors deep reflection seismic data
Authors D. Rappin, J. M. Marthelot and E. de BazelaireThe discontinuous aspect of deep crustal reflections on stacked seismic sections has led us to a study of the original records, the true amplitude shot gathers. We look at the amplitudes, the lateral continuity of reflections and the frequency content of the signal in order to obtain more precise informations about the physical properties and the geometrical structures in the crust. These studies are done on ECORS deep reflection seismic profiles and can also be done on seismic exploration data.
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Geophysical study of the Ross Sea (Antarctica)
Authors M. Pipan, J. Finetti, A. D. Ben and R. GelettiThe interpretation of a large amount of multichannel seismic reflection sections recorded during the first Italian geophysical cruises to Antarctica (1978-88, 1988-89), performed by OGS-Trieste, has revealed new and interesting elements about the structure, the stratigraphy and the evolution of the Pacific sector of the Antarctic Platform.
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Statistical investigations of the density-velocity relation using the database DABACOS
More LessEmpirical correlations between seismic velocities and bulk densities of rocks are of particularly interest for practical purposes like combining results of seismic and gravity measurements. Relations like the Nafe-Drake-curve or the Gardner-formula are used to get a priori data for the estimation of a density model by seismic data. Beyond that, they are frequently employed for theoretical penetration studies of seismic waves and for the calculation of synthetical seismograms. Combined with deep drilling programs relations for crystalline rocks become even more important in the near future.
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Application of fuzzy pattern recognition to seismic stratigraphy
Authors B. Lashgari and R. E. EstillA new method for seismic stratigraphic analysis is proposed and its effectiveness on seismic data is discussed. The method utilizes seismic attributes and the concept of fuzzy pattern recognition to automatically track horizons and identify termination points. In sequence stratigraphy this is an effective approach in providing valuable information to interpreters in relation to sequence boundaries, seismic facies, and horizon mapping.
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Logical object model and derived exchange format for 3D subsurface model data
Authors I. L. Ritsema, S. Pen and Th. KemmeIn the Oil and Gas Exploration and Production Industry many data are being exchanged or traded. For many object classes commonly agreed data exchange formats exist (e.g. SEGY. LIS. UKOOA. OLG. etc.). An important object class without any standard exchange format is the class of 3D geological or geophysical data. In the Geoscience Research Programme funded in part by the EC (OG XII) a logical model has been developed for objects describing 3D subsurface modeis. From the logical object model three types of implementations and a exchange format can be derived.
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Interpretation and geomodelling of diapiric structures using the SlIS workstation
Authors D. Jackson, A. Carter and J. FarnsworthThe value of workstations for exploration and development has long been appreciated, but recently in addition to the interpretation and general mapping capabilities, interactive geomodelling techniques carried out wholly within the workstation environment are becoming available. using examples from recently drilled diapiric plays in the Central North Sea, we illustrate how interactive interpretation and geomodelling have been applied during a series of pre-drill/ post-drill phases.
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Practical use of advance software in an interactive stratigraphic and structural analysis of roar field: A case history
Authors I. Abatzis and J. D. KerrThe Roar structure is situated in the Danish Central Graben and is surrounded by the Bo, Boje, Adda, Tyra and Jens structures. It is a low relief porous chalk closure generated by structural inversion during the Late Cretaceous and Tertiary periods. In addition, the general increase in subsidense toward the center of the Central Graben in Tertiary times has also influenced the structural evolution.
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Visualization of map and seismic attributes
Authors H. R. Nelson Jr., S. Mastoris and C. HuxohlNew map and seismic attributes have been developed for use on interactive seismic workstations. These techniques were applied to the interpretation of both geologic structure and stratigraphy from 3d seismic surveys from Canada and the Gulf of Mexico. In both of these geological domains the new attributes provided new infonnation leading to a more complete and accurate interpretation. We will first describe the seismic attributes used to assist identifieation of reservoir reflectors, and then describe the map attributes and how they aided the interpretation. Specifically, we show how these map and seismic attributes explained why wells in one part of a project area were more productive than those in other places in the project, and how this interpretation fonnulated new leads for additional well locations.
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