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63rd EAGE Conference & Exhibition
- Conference date: 11 Jun 2001 - 15 Jun 2001
- Location: Amsterdam, Netherlands
- Published: 11 June 2001
1 - 20 of 516 results
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Processing and Analysis of PS-Wave Data from a 3D/3C Land Survey for Fracture Characterization
Authors R.R. Van Dok, J.E. Gaiser and J.E. MarkertP117 PROCESSING AND ANALYSIS OF PS-WAVE DATA FROM A 3-D/3-C LAND SURVEY FOR FRACTURE CHARACTERIZATION Summary 1 The investigation of S-wave birefringence (splitting) using 3-D converted P to S-waves (PS-waves) is an important tool for characterizing reservoir fractures. In azimuthally anisotropic media fracture intensities are directly related to traveltime differences between the fast and slow S-waves and fracture orientations are related to the polarization direction of the fast S-wave. These effects are accurately analyzed in a 3-D/3-C survey from the Green River basin in Wyoming to preserve meaningful azimuthal variation in amplitude and traveltime. Estimates of the principal PSwave fast
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Anisotropic Prestack Depth Migration and Model Building
Authors R. Bloor, P. Whitfield and K. FiskA-01 ANISOTROPIC PRESTACK DEPTH MIGRATION AND MODEL BUILDING R. BLOOR P. WHITFIELD and K. FISK WesternGeco 10001 Richmond Avenue Houston TX 77042 USA Summary 1 The majority of the subsurface is anisotropic to some extent but in most cases the processing of seismic data ignores anisotropy. Ignoring anisotropy can result in significant mispositioning of events due to biased velocity values and in prestack space difficulty in aligning events at different offsets. Well mis-ties and vertical seismic profile (VSP) data can help constrain the nature and quantity of anisotropy. Incorporating anisotropy in depth imaging can result in more accurate seismic images.
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Anisotropic Beam-Stack Kirchhoff vs Wave Equation Imaging on PC Clusters
Authors J.B. Bednar and C.J. BednarA-02 ANISOTROPIC BEAM-STACK KIRCHHOFF VS WAVE EQUATION IMAGING ON PC CLUSTERS Abstract 1 This paper discusses advanced imaging in acoustic elastic and anisotropic 3D media on large massively-parallel personal computer clusters. The focus is on parameter estimation methods and the technology pertinent to image data recorded over such models. Both synthetic and real data sets are used to demonstrate that existing technology though computationally intensive is eminently feasible on very attractively priced hardware. While the beam-stack approach to Kirchhoff migration has significant speed advantages full wave-equation methodologies are shown to provide superior accuracy and images. Introduction The recent advent of
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Addressing Anisotropy in Prestack Depth Migration - a Southern North Sea Case Study
Authors K. Hawkins, H. Kat, R. Leggott and G. WilliamsA-03 ADDRESSING ANISOTROPY IN PRESTACK DEPTH MIGRATION – A SOUTHERN NORTH SEA CASE STUDY K. HAWKINS 1 H. KAT 2 R. LEGGOTT 1 and G. WILLIAMS 1 Abstract 1 In order to optimise gas production from Rotliegend reservoirs located offshore Holland it is crucial to obtain both accurate imaging and depth control of seismic data. Prestack depth migration is essential to achieve accurate imaging in this demanding geological environment. However isotropic imaging velocities differ from vertical well velocities due to transverse isotropy. Use of a prestack depth migration algorithm that comprehends anisotropy has the advantage of providing greater imaging accuracy
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Technology Offers New Insight in a Mature Area - a 3D PreSDM Case Study from the Dutch N Sea
Authors F.J. Dewey, P. Whitfield and M. KingA-04 TECHNOLOGY OFFERS NEW INSIGHT IN A MATURE AREA – A 3D PRESDM CASE STUDY FROM THE DUTCH N SEA F. DEWEY 1 P. WHITFIELD 2 and M. KING 3 Introduction 1 Exploration in Blocks K10 and K13 in the Broad Fourteens Basin of the Dutch offshore started in 1968 and over 30 exploration wells have since been drilled resulting in 7 producing fields. As these fields enter their final years of production new technology has been deployed to identify additional reserves and extend the producing life of this mature area. Imaging problems The area is structurally complex with large
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Imaging the Unimaginable
Authors S.J. Kapoor, C. Liu and S. TraresA-05 IMAGING THE UNIMAGINABLE S.J. KAPOOR C. LIU and S. TRARES WesternGeco 10001 Richmond Avenue Houston TX 77042 USA 1 Summary 3-D prestack depth imaging will become the standard seismic exploration tool used by oil and gas companies exploring for hydrocarbons. Recent successes such as the Crazy Horse and Mad Dog prospects in the deepwater Gulf of Mexico are increasing exploration activity. The complex geological structures the presence of allochthonous salt and wells costing 50 million dollars or more are common. Balancing exploration potential risk and return is key to a successful exploration program in the deepwater. Risk can be
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T Migration and Velocity Analysis - Application to Real Data from the Red Sea
More LessA-06 W-MIGRATION AND VELOCITY ANALYSIS – APPLICATION TO REAL DATA FROM THE RED SEA TARIQ A ALKHALIFAH 1 Institute for Astronomy and Geophysical Research KACST PO Box 6086 11442 Riyadh Saudi Arabia SUMMARY Imaging the pre-alt reflections for data acquired from the coastal region of the Red Sea is a task that requires prestack migration velocity analysis. Conventional poststack time processing lacks the lateralinhomogeneity capability needed for such a problem. Prestack migration velocity analysis in the vertical time domain reduces the velocity-depth ambiguity usually hampering the performance of prestack depthmigration velocity analysis. In prestack τ migration velocity analysis we keep
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Comparison of Kinematic and Preserved Amplitude PsDM for AVO Analysis
Authors P. Thierry, L. Lenain, R.M. Baina, V. Devaux and H. CalandraA-007 COMPARISON OF KINEMATIC AND PRESERVED AMPLITUDE PSDM FOR AVO ANALYSIS. L. LENAIN 1 R. M. BAINA 2 P. THIERRY 3 V. DEVAUX 4 and H. CALANDRA 4 1 TotalFinaElf now at University of DELAWARE NEWARK USA 2 Ipedex detached to École des Mines de Paris 3 École des Mines de Paris 35 rue Saint Honoré F- 77 305 Fontainebleau 4 TotalFinaElf av. Larribau F-64018 Pau Summary. In AVO inversion after prestack depth migration the question of amplitude preservation remains open. It is often tackled by correcting for amplitude decay in the traces at the pre-processing stage followed by “kinematic”
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Regional Velocity Models of the Netherlands Territory
More LessA-08 REGIONAL VELOCITY MODELS OF THE NETHERLANDS TERRITORY J.C. DOORNENBAL 1 TNO-NITG Netherlands Institute of Applied Geoscience-National Geological Survey Department of Geo-Energy PO Box 80015 3508 TA Utrecht The Netherlands Introduction The regional subsurface onshore mapping project of the "Geological Atlas of the subsurface of the Netherlands" was started in 1985 at the former Geological Survey of the Netherlands. This project is carried out with seismic and well data. It is now in its final stage. For this project regional depth and isopach maps are created (scale 1:250.000). The mapped intervals comprise eight major lithostratigraphic units in the range of
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Suppression of Power Line Interference in Seismic Records
More LessA-09 SUPPRESSION OF POWER LINE INTERFERENCE IN SEISMIC RECORDS F. KIRCHHEIMER WesternGeco P.O. Box 510530 Buchholzer Str. 100 30655 Hannover Germany Abstract 1 Seismic records often contain electromagnetic noise from nearby power lines. An efficient procedure to remove this type of interference is therefore desirable. For everyday use in the preprocessing stage such a process should have no impact on uncontaminated data should not affect the spectra of contaminated data more than necessary and should be able to work with minimal a priori knowledge of the characteristics of the noise. A method is presented that largely meets these requirements. It
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Detection of Ground Roll for Multicomponent Point-Receiver Data
More LessA-10 DETECTION OF GROUND ROLL FOR MULTICOMPONENT POINT-RECEIVER DATA Abstract 1 A method for the detection and filtering of ground roll is introduced which is suitable for the application on point-receiver data. The detection method utilizes the polarization properties of ground roll and additionally takes into account the relatively high amplitudes of ground roll compared to other parts of the seismic section. The filtering is performed via an adaptive signal processing technique especially designed for point receiver data. It attenuates dispersive nonstationary coherent noise by using reference traces in the vicinity of the trace to be filtered as a reference
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Multi-Directional 3D Acquisition and Processing for Subsalt Imaging
Authors B. VerWest, R.S. Hobbs and J. YoungA-11 MULTI-DIRECTIONAL 3D ACQUISITION AND PROCESSING FOR SUBSALT IMAGING Abstract 1 B.VER WEST R. S. HOBBS and J. YOUNG Veritas DGC Inc. 10300 Town Park Houston TX 77072 USA 3D Pre-stack depth migration (PSDM) is commonly used for improving image quality adjacent and under complex salt bodies in the Gulf of Mexico. A study has been conducted within a mini-basin of the Garden Banks area of the Gulf of Mexico to examine the benefits of combining multi-directional datasets together through depth processing to yield the most optimum near-salt and sub-salt image. Two 3D volumes of differing vintages but similar acquisition
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Over/Under Acquisition - Breaking the Resolution Limits
More LessA-12 OVER/UNDER ACQUISITION – BREAKING THE RESOLUTION LIMITS S. GRION J. HOBRO J. BARSCH and S. RONEN Summary 1 Seismic resolution is limited by source and receiver ghosts. In marine acquisitions shallow source and receivers increase high frequency content but attenuate the low frequencies fundamental for stratigraphic and structural inversion. On the other hand deep source and receivers enhance the low frequencies at the expense of the high. The combination of data acquired with different cable depths is a solution to this problem and is usually referred to as over/under combination. Over/under can combine in a single image the high-frequency
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Seismic Crew Interference and Prestack Random Noise Attenuation on 3D Marine Seismic Data
Authors N. Gülünay and D. PattbergA-13 SEISMIC CREW INTERFERENCE AND PRESTACK RANDOM NOISE ATTENUATION ON 3-D MARINE SEISMIC DATA N. GÜLÜNAY and D. PATTBERG WesternGeco 10001 Richmond Avenue Houston TX 77042 USA Abstract This paper presents a method of removing strong seismic interference noise as well as random noise from shots acquired in 3-D marine surveys. This process will allow boats to reduce down time when other crews are operating in the same area. The method is applied to each frequency slice of the frequency-source-receiver volume obtained by time only Fourier transform of a small time-space (source and receiver) volume of data. These volumes overlap
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Decimating Acquisition Using 3D SCO
Authors N. Bienati, E. Loinger, P. Mazzucchelli and U. SpagnoliniA-14 DECIMATING ACQUISITION USING 3D SCO Summary 1 Pre-stack data interpolation is always an attractive issue for the potential related acquisition cost reductions. Once designed on the base of an acceptable cost-quality trade-off a field layout can be adequately decimated thus leaving only those shotpoints that are strictly necessary to recover the final image quality by shot-infilling. This decimated layout is called minimal acquisition (MA) layout. Of course the MA layout depends on the geophysical targets and the data quality which are given as well on the interpolation method and strategy which therefore must be carefully selected. In this paper
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Regularising 3D Data Using Fourier Reconstruction and Sparse Inversion
Authors P.M. Zwartjes and C.O.H. HindriksA-015 REGULARISING 3D DATA USING FOURIER RECONSTRUCTION AND SPARSE INVERSION P. M. ZWARTJES and C. O. H. HINDRIKS Delft University of Technology Lab. of Acoustic Imaging and Sound Control PO Box 5046 2600 GA Delft The Netherlands Abstract Fourier reconstruction yields a better regularisation than can be obtained by a simple binning procedure. The method consists of estimating the Fourier coefficients by least-squares inversion with a priori information. The sparse distribution of energy over the Fourier coefficients can be used as a priori information. Resulting algorithms perform significantly better in a 3D synthetic experiment than conventional Fourier reconstruction with a
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Analysis of 3D Acquisition Geometries with Focal Beams
Authors A.W.F. Volker, G. Blacquière and A.J. BerkhoutA-16 ANALYSIS OF 3-D ACQUISITION GEOMETRIES WITH FOCAL BEAMS A.W.F. VOLKER G. BLACQUIÈRE and A.J. BERKHOUT Abstract 1 The amplitude accuracy of a seismic acquisition geometry is strongly dependent on the source and detector configuration. The concept of focal beam analysis is an ideal starting point to understand the relation between the source-detector geometry and the amplitude accuracy observed in a 3-D image. In this paper the emphasis is on the study of the dependency of the focal beams on the subsurface location. The continuity of the target point ‘illumination’ plays a vital role in achieving a small acquisition footprint.
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Stacking - and the Importance of Offset (x)
By I. GauslandA-17 STACKING – AND THE IMPORTANCE OF OFFSET (x) INGEBRET GAUSLAND Introduction 1 Offset (x) is an important parameter in processing of seismic data but surprisingly little is documented on the impact of offset on stacking. I have in previous presentations stated that stacking is indeed a beamforming process and in this presentation I will give a more fundamental background for my earlier statements. Most geophysicists will know that mis-stacking the data by choosing a slightly higher than optimum stacking velocity will achieve additional multiple attenuation. This is due to the “beamforming” type stack response. Therefore it should be obvious
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Removing NMO Stretch Using the Radon and Fourier-Radon Transforms
By G.J. HicksA-18 REMOVING NMO STRETCH USING THE RADON AND FOURIER-RADON TRANSFORMS GRAHAM J HICKS Introduction 1 Department of Geological Sciences and Geological Engineering Queen’s University Kingston K7L 3N6 Canada Fundamental to the creation of the traditional Common Midpoint (CMP) stack is a normal-moveout (NMO) correction. It has long been known that NMO stretch distorts the recorded wavelet limiting the offset range that can be successfully stacked without reducing the resolution of the stack. I describe a method for removing NMO stretch during stacking that uses the parabolic Radon transform (PRT). I also introduce a new transform that is a combination of
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An Efficient Method for Sorting Large-Volume Seismic Data
Authors M.H. Huwaidi, Y. Luo and K. GunaratnamA-19 AN EFFICIENT METHOD FOR SORTING LARGE-VOLUME SEISMIC DATA Abstract 1 The channel count in our 3D seismic crews is increasing very rapidly. At Saudi Aramco the last count as of writing this paper has reached 3840 channels/VP. Many seismic processing algorithms require data to be sorted in special orders such as common mid-point and common receiver gathers. For very large [1 tera (10 12 ) bytes or larger] data sets sorting the data efficiently with limited computer resources is a non-trivial task. In this paper we introduce a new and efficient sorting method. We will refer to it as
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