- Home
- Conferences
- Conference Proceedings
- Conferences
63rd EAGE Conference & Exhibition
- Conference date: 11 Jun 2001 - 15 Jun 2001
- Location: Amsterdam, Netherlands
- Published: 11 June 2001
21 - 40 of 516 results
-
-
High Resolution Time Delay Estimation Based on Third-Order Statistics Domain
Authors V.D. Vrabie and J.I. MarsA-20 HIGH RESOLUTION TIME DELAY ESTIMATION BASED ON THIRD-ORDER STATISTICS DOMAIN V.D. VRABIE and J.I. MARS Abstract 1 The seismic prospecting aim is to obtain structural and geological information. The time delay evaluation is an essential operation often necessary in the multidimensional signals treatments. Into seismic processing this operation is carried out in a systematic way before using the waves separation procedure and velocities evaluation. All these operations and especially the waves separation tools are very sensitive to a good waves alignment. Classical time delay estimation relying the cross-correlation (second order statistics) is often used. But in case of correlated
-
-
-
Compression Denoising - Using Seismic Compression for Uncoherent Noise Removal
Authors L.C. Duval and V. Bui TranA021 COMPRESSION DENOISING: USING SEISMIC COMPRESSION FOR UNCOHERENT NOISE REMOVAL L. C. DUVAL and V. BUI TRAN IFP Technology Department 1 et 4 avenue de Bois-Préau 95852 Rueil-Malmaison Cedex France E-mail: [email protected] Summary Wavelet related techniques have been proved successful in many seismic processing applications such as filtering or compression. While seismic data compression is not yet widely accepted we propose a compression based on filter banks as a means to remove uncoherent noise from seismic data and thus improve the SNR. Results are demonstrated on synthetic data. Introduction and overview of time-frequency techniques If we let data analysis aside
-
-
-
Rough Seas and Statistical Deconvolution
More LessA-22 ROUGH SEAS AND STATISTICAL DECONVOLUTION E. KRAGH and R. LAWS 1 Schlumberger Cambridge Research High Cross Madingley Road Cambridge CB3 OEL UK Summary: The rough sea ghost response varies along the streamer from shot to shot and with time along the seismic trace. In this paper we examine the application of statistical deconvolution to reduce the rough sea error. Although this conventional method incorrectly assumes wavelet stationarity a partial correction can be achieved provided some modification of the standard application is carried out; the design window should be no longer than 1 s and the application window should lie
-
-
-
Mixed Phase Surface Consistent Deconvolution without Phase Unwrapping
Authors C. Perkins and R. Calvert3 signal event is far more aligned after deconvolution has been applied demonstrating that the phase spectrum of the surface consistent distortions have been correctly estimated. msec Figure(1a) CDP gather displaying surface consistent phase rotations and time shifts with added noise Figure(1b) synthetic CDP gather from figure (1a) after surface consistent deconvolution The second example shows the effectiveness of the algorithm when applied to a real land vibroseis data set. Prior to deconvolution inverse Q-filtering deterministic zero phasing refraction statics surface consistent residual statics NMO and a sliding gate amplitude equalization had been applied to the data. The deterministic zero
-
-
-
Simultaneous Least Squares Deconvolution and Kriging Using Conjugate Gradients
Authors J. Kane, W. Rodi and M.N. ToksözA-024 SIMULTANEOUS LEAST SQUARES DECONVOLUTION AND KRIGING USING CONJUGATE GRADIENTS JONATHAN KANE WILLIAM RODI and M. NAFI TOKSÖZ Earth Resources Laboratory Massachusetts Institute of Technology 42 Carleton St. Cambridge Ma. 02142 Summary Least squares deconvolution is a method used to sharpen tomographic images of the earth by undoing the bandlimiting effects imposed by a seismic wavelet. Kriging is a method used by geoscientists to extrapolate and interpolate sparse data sets. These two methodologies have traditionally been kept separate and viewed as unrelated fields of research. We demonstrate the connection between these methods by deriving them both as examples of linear
-
-
-
Efficient Amplitude-Preserved Prestack Depth Migration
Authors F. Audebert, C. Hanitzsch, S. Jin and A. TuraA-25 EFFICIENT AMPLITUDE-PRESERVED PRESTACK DEPTH MIGRATION Abstract 1 An efficient approximation to amplitude-preserved prestack depth migration is presented. The patented strategy can reduce the computational cost to little more than the cost of standard PreSDM. The technique splits the process into two steps: a standard PreSDM (that also keeps the prestack migrated data) followed by a second separate process that accurately recovers postmigration amplitudes and reflection angles. Important practical advantages can result from this split. An application to data from the North Sea is presented. Introduction CHRISTIAN HANITZSCH 1 2 SIDE JIN 1 3 ALI TURA 1 4 and FRANCOIS
-
-
-
Monte Carlo Wavefield Imaging of 3D Prestack Data
Authors L. Cazzola, E. Bonomi, L.M. Brieger and F. ZanolettiA-26 MONTE CARLO WAVEFIELD IMAGING OF 3D PRESTACK DATA L. CAZZOLA 1 E. BONOMI 2 L. M. BRIEGER 2 and F. ZANOLETTI 1 Abstract 1 We present a new imaging methodology based on the depth extrapolation of a single dataset obtained by randomly compressing sources and shot-gathers. In this work a Monte Carlo imaging condition was implemented with a Phase Shift Plus Interpolation (PSPI) extrapolating kernel and tested on the SEG- EAGE salt model. This study demonstrates that wavefield 3D prestack depth migration is possible for industrial applications providing high quality results in reasonable computational times. Introduction Prestack depth migration
-
-
-
Cross-Spread Imaging in the Wavenumber Domain
Authors P. Mazzucchelli and F. Rocca���� ��������������������������� ����������������� ��������������� � ���������� � �������� � ��������������������������������������������������������������������������������� ��� �������� ��������������������������������������������������������������������������������������������������� ����������������������������������������������������������������������������������������������� ������������������������������������������������������������������������������������������������� ��������������������������������������������������������������������������������������������� ��������� ��� ����� ����������� ������������ �������� ����� ������������ ���� ��������������� ��� ���� ��������� ������������ �� �������� ������������ ������� ���� ����� ��� ���� ��� ���� ����������� ���������� �� ����� ������� �� ������������������������������������������������������������������������������������������������ ���� ������� ����� ��� �������� ��� ���� ��� ���������� �������� ������ ������� ����������� ���������� ������������ ����������� ��� ���� ��� �� ��� �������� ��������� ��� ���� ��� �������� ���������� ������� ����������� �������������������������������������������� ���� ��������������� ���� ������������� ��� ����������������������������������� ��� ���� ��������� ����� ������� ������� ��� ������� ��������� �������� ������� ����������� ������ �������� ������������ ���
-
-
-
Determining the Optimum Migration Aperture from Traveltimes
Authors C. Vanelle and D. GajewskiA-028 DETERMINING THE OPTIMUM MIGRATION APERTURE FROM TRAVELTIMES C. VANELLE and D. GAJEWSKI Institute of Geophysics University of Hamburg Bundesstr. 55 20146 Hamburg Germany Summary True amplitude migration is a task of high computational costs. These can be significantly reduced if the involved summation is carried out only over traces which really contribute to the stack result i.e. a limited aperture instead of the whole aperture of the expriment. We introduce a method to determine an optimum migration aperture that needs only traveltime tables as input information. These are also used for the computation of the true amplitude weight functions.
-
-
-
3D FD Prestack Depth Migration Using Cylindrical Wave Data
Authors B. Duquet, P. Lailly and A. Ehinger¡ £ ¥ § ¨ � ¨ � � � � � � � ¨ � � � � � � � � � � � � � � � � � � � � � � � � � � � � � ¨ � � � � � � � ¨ � � � � � � � � � � � � � �� �� � � � � � � � �� � � � � � ���� � � ��� � � � �� � � � �
-
-
-
AVA Analysis and Compensation on Common Image Gathers in the Angle Domain
Authors S. Brandsberg-Dahl, M.V. de Hoop and B. Ursin�� are the normalized polarization vectors receiver � at the source and is two-way traveltime is the is the gradient of two-way traveltime is the ray amplitude. The describes where� and� the contrast source radiation pattern at the image point. The combination of sources and receivers will dictate �� and� matrix� data � the maximum possible coverage �� in migration dip and hence the is also data dependent. The complete image is constructed by an additional stack over scattering angle and azimuth. support� The ‘measure’ in equation (1) � is modified by introducing the conical in migration dip and the
-
-
-
A Causality Based Imaging Method
Authors H. Poot, J.T. Fokkema and C.P.A. WapenaarA-031 A CAUSALITY BASED IMAGING METHOD Summary H. POOT J.T. FOKKEMA and C.P.A WAPENAAR Delft University of Technology Subfaculty of Applied Earth Sciences Mijnbouwstraat 120 2628 RX Delft An imaging condition is derived based on the causality principle. This condition determines directly the velocity contrast over an interface using the wavefields measured at this interface. We assume the velocity below the interface is constant in vertical (but not necessarily in lateral) direction for a thin layer. Using the reciprocity theorem we can now calculate the wavefield below this thin layer in the case it was removed and replaced by a
-
-
-
Theory of Daylight/Interferometric Imaging - Tutorial
More LessA-032 Abstract THEORY OF DAYLIGHT/INTERFEROMETRIC IMAGING: TUTORIAL GERARD T. SCHUSTER University of Utah Salt Lake City Utah 84112 U.S.A I present the general theory of interferometric imaging (II). Interferometric imaging is any algorithm that inverts crosscorrelated data for the reflectivity or source distribution. As examples I show that II can be used to image arbitrary reflectivity distributions by migrating ghost reflections in passive seismic data and II generalizes the receiver-function imaging method used by seismologists II can be used to migrate freesurface and peg-leg multiples in CDP data. I also show how source distributions can be imaged from passive seismic
-
-
-
2D Elastic Model for Wavefield Investigations of Subsalt Objectives, Deep Water Gulf of Mexico
Authors D. Stoughton, J. Stefani and S. MichellA-33 2D ELASTIC MODEL FOR WAVEFIELD INVESTIGATIONS OF SUBSALT OBJECTIVES DEEP WATER GULF OF MEXICO SUMMARY 1 A full elastic 2D synthetic model has been generated by the SMAART* Joint Venture Consortium to simulate the primary signal and noise characteristics of sub-salt objectives associated with the deep-water environment of the Gulf of Mexico. A very detailed geologic model has been derived based on real exploration data and has served as input to a finite difference shot computation process. The data has been rigorously computed with many offsets and can be decimated to mimic shot geometries of long offset streamer data.
-
-
-
Surface Related Multiple Suppression and Imaging of SMAART JV Pluto 1.5 Dataset
Authors B. VerWest, M. Karazincir and N. CooperA-34 SURFACE RELATED MULTIPLE SUPPRESSION AND IMAGING OF SMAART JV PLUTO 1.5 DATASET B. VER WEST 1 M. KARAZINCIR 1 and N. COOPER 2 Abstract 1 The removal of multiple energy from deep water subsalt data is a major challenge facing exploration geophysics. The strong velocity contrasts at the water bottom and salt interfaces generate strong multiples which frequently obscure the relatively weak signals from the subsalt targets. In addition the multiples are frequently non-hyperbolic because of the complex structure of the salt and this makes them difficult to remove with parabolic Radon transform techniques. Finally the deep water sediments
-
-
-
Turning-Ray Tomography for Statics Solution
Authors J. Criss, D. Epili and D. CunninghamA-35 TURNING-RAY TOMOGRAPHY FOR STATICS SOLUTION D. EPILI J. CRISS and D. CUNNINGHAM Green Mountain Geophysics An Input/Output Inc. Company 361 Centennial Parkway Suite 200 Louisville CO 80027 USA 1 Summary A tomographic imaging technique combined with delay time analysis is proposed for constructing near surface velocity structure from first arrivals. Analysis on a 2-D data set from Eastern Colorado and a 3-D data set from Western Canada indicated that traditional refraction techniques provide a better short period statics solution in presence of a layered model of varying velocity and thickness whereas turning ray tomography provide a better solution in
-
-
-
First-Arrival Tomography for Near-Surface Model Building
Authors S. Cheadle, T. Zhu, A. Petrella and S. GrayA-36 FIRST-ARRIVAL TOMOGRAPHY FOR NEAR- SURFACE MODEL BUILDING Summary 1 A new method has been developed for tomographic determination of the near-surface velocity structure from first arrivals. It treats the first arrivals as direct body waves propagating along turning rays and represents the velocity structure with a grid model. Estimation of the grid’s node velocities is formulated as an iterative regularized linear least-squares problem. The traveltimes and raypaths required for the inversion are calculated by a highly efficient grid raytracing technique. Experiments with both synthetic and real data show that the new tomographic method is accurate and capable of recovering
-
-
-
Incorporating Head Waves and Diving Waves in Refraction Tomography
Authors K. Osypov, J. Green, O. Zdraveva and M. RhodesA-37 INCORPORATING HEAD WAVES AND DIVING WAVES IN REFRACTION TOMOGRAPHY Summary 1 Refraction methods are usually divided into two categories: head-wave and diving-wave based. By choosing one of these methods one assumes first arrivals to be the onset of a certain wave type. However the decision on which assumption is better for a particular survey is seldom obvious as it implies the knowledge of a model type. This dilemma may be resolved by tau-p refraction tomography which is an emerging technology that complements other well-known methods for modeling the near surface. This method builds the near-surface model from the tau-p
-
-
-
Processing with Offset-Vector-Tile Gathers
More LessA-38 Processing with offset-vector-tile gathers Abstract Conventional prestack processing suffers from the absence of proper common-offset gathers in the crossed-array geometries. This requires an approach to prestack processing that recognizes the particular requirements of those geometries. This paper provides a strategy for prestack processing based on the construction of pseudo-minimal data sets (pMDSs) i.e. data sets which are as nearly as possible MDSs yet extend across the whole survey area. The strategy assumes 3D symmetric sampling of the input data. The most suitable pMDS in orthogonal geometry is a collection of offset-vector tiles (OVT gathers). Each OVT contains data with
-
-
-
The Use of 4D Seismic in Reservoir Management
Authors J.M. Marsh, G. Bagley, A. Lewis, J. McGarrity, T. Nash, R. Parr, I. Saxby and D. WhitcombeF-01 THE USE OF 4D SEISMIC IN RESERVOIR MANAGEMENT J MARCUS MARSH GRAEME BAGLEY ANDREW LEWIS JOHN MCGARRITY 1 Summary In mid 1999 BP acquired a 3-D survey over the West of Shetland area specifically for time-lapse interpretation of the reservoir dynamic behavior over the component fields. This was described at the EAGE meeting last year i . This formed a turning point in BP’s use of 4-D from experimentation to commercial use. The results were very useful in field management and well planning. Before that it had acquired a number of repeat 3-D seismic surveys which in addition to
-