Accurate wavelet estimation is critical to the success of any seismic inversion. A method of prestack time migration based on the principles of prestack kirchhoff time migration that can be applied to both 2d and 3d data. Prestack kirchhoff migration is based on the scatterpoint principle that assumes reflectors may be defined by scatterpoints, and that prestack seismic data becomes the superposition of the corresponding cheops pyramids. Case study data management highlevel seismic data flow and process. Statoil integrates pre and poststack seismic data prosource seismic improves data access, quality, and. Here you can access our latest news, download articles or technical papers from our library, or learn more about our upcoming conferences and events. Unprocessed shot records with geometry loaded in trace headers a time window of processed prestack gathers with moveout applied a final image vsp data well logs inversion results to download, see instructions below. The prestack seismic data is transformed to the angle domain before inversion. Bg group plc or any of its respective subsidiaries, affiliates and associated companies or by any of their respective officers, employees or agents makes no representation or warranty, express or implied, in respect to the quality, accuracy or usefulness of this repository. By joanne wang prestack seismic data is applied routinely in the process of quantitative seismic interpretation qsi to generate varieties of seismic attributes, in order to estimate reservoir. Direct reservoir property estimation based on prestack. Because diffraction energy is generally weak in seismic data and particularly in prestack data, noise attenuation and edge enhancement methods are applied on the instantaneous phase of the seismic. Jun 21, 2018 seismic inversion and well log data were integrated to image and characterize lithofacies at reservoir zones of interest.
An amplitudepreserving processing procedure is implemented for the seismic data. Other combinations of elastic parameters such as pimpedance, vpvs ratio and density are equally possible. We assume that wave mode conversions, interbed multiples, and anisotropy effects can be neglected after processing. The inversion is defined in a bayesian setting where the complete solution is the posterior model. Prestack migration reservoir characterization schlumberger. Prestack data are characterized by large data size and rich information. Prestacklinearmodelling operator is used for modelling of both 1d and 2d synthetic prestack seismic data using 1d profiles or 2d models of different subsurface elastic parameters pwave velocity, swave velocity, and density as input.
A tensor higherorder singular value decomposition for. Some techniques of using prestack seismic data, will first reduce. Open data on the seg wiki is a catalog of available open geophysical data online. Until the migration step, seismic data are merely recorded traces of echoes, waves that have been reflected from anomalies in the subsurface. The petrel prestack seismic interpretation plugin enables prestack seismic visualization, interpretation, and interactive processing to bridge the gap between prestack and poststack interpretation workflows. Clonal selection based intelligent parameter inversion. To understand the distinction between impedance and reflectivity, refer to figure 1, which shows the different ways in which geologists and geophysicists look at their data. While it is possible to estimate velocities from the conventional pwave seismic data, it is.
The success of a quantitative seismic interpretation project requires highquality prestack seismic data. Integrated prestack depth migration of vsp and surface seismic data in order to test the new, integrated prestack depth migration algorithm, a numerical model was developed based on the interpretation of the field data. Our paper is focused on kinematic or geometric aspects of time migration and demigration. Optionally opendtect can be extended with closed source commercial plugins. Based on logging and seismic data, we can perform a feasibility analysis of the proposed joint inversion technique for reservoir elastic and petrophysical parameters via prestack seismic faciescontrolled joint inversion for hydrocarbon sweet spot prediction. Segyio is a small lgpl licensed c library for easy interaction with segy and seismic unix formatted seismic data, with language bindings for python and matlab. Interpretation of prestack seismic data is still not widely used in the industry primarily because of the sheer size of the input data involved and a lack of efficient tools to make the data readily usable. Details of the model at the target level are shown in figure 3a. Estimating seismic dispersion from prestack data using. Comprehensive seismic data analysis and interpretation with. The imaging deficiencies of 2d seismic profiling were remedied by the implementation of 3d seismic data acquisition, which allows data processing to migrate reflections to their correct image coordinates in 3d space. However, due to the inclusion of ex cessive redundancy, effective feature extraction from prestack seismic data becomes critical.
Citeseerx document details isaac councill, lee giles, pradeep teregowda. The effects of seismic data conditioning on prestack. Introduction prestack depth migration algorithms are usually divided into two classes. Rich reservoir parameter information can be obtained through inversion of prestack data. Feb 07, 2016 the success of a quantitative seismic interpretation project requires highquality prestack seismic data.
The best approach to use varies depending on the goal model building, migration, avo and stacking all have different requirements for the input data. Opendtect is an open source seismic interpretation software system for processing, visualizing and interpreting multivolume seismic data, and for fasttrack development of innovative interpretation tools. We discuss how this model can be obtained at the very end of the methodology part, supported by two numerical examples. Using matlab beyond the geophysicists sandbox charles jones and james selvage, bg group within the seismic geophysics community, matlab is generally considered a useful tool for developing prototype algorithms, but not for scaling to production. Data provided by the new zealand crown minerals include a full angle stack, and near, mid, and far stacks. Accurate estimation of density from the inversion of. But what makes prestack seismic data particularly important is that they open our. However, since no bathymetric data was simultaneously collected with the seismic data we have no way of proving that the added 6 ms does exist for this data. Common scatter point csp gathers are created as an intermediate step for each output migrated trace.
Processed longoffset, broadband 2d seismic data prestack time migrated full offset stack and angle stacks for newly acquired regional. The interpretation of 3d prestack seismic data involves poststack and prestack seismic attribute. The readme file containing an explanation of the data including data formats, software that can be used, processing, and projection and datum used. Useful reservoir parameter information can be gained through inversion of seismic information to effectively carry out exploration work. The data has been collected for the period 19822014. Once data are spatially regularized so that the resulting prestack data have uniform fold of coverage and have been corrected for sourcereceiver azimuth, then, in principle, any of the three categories of migration algorithms kirchhoffsummation, finitedifference, or frequencywavenumber, can be used to perform 3d prestack depth migration. Westerngeco has an extensive range of prestack migration algorithms to handle all geological complexities and seismic acquisition environments and designs, including the latest fullazimuth surveys. To understand the distinction between impedance and reflectivity, refer to figure 1, which shows the different ways. Prestack seismic faciescontrolled joint inversion of. Prestack seismic data carries much useful information that can help us find more complex atypical reservoirs. In order to obtain maximum value from your recorded seismic, you need to condition it suitably. Kinematic time migration and demigration of reflections in.
Model velocities were assigned from sonic logs from the vsp well. A supervised modelbased simultaneous inversion of poisson impedance pi and crossplot was carried out on the prestack seismic data to understand the lithofacies classification and fluid types. Integrated prestack depth migration of vsp and surface. Seismic inversion and well log data were integrated to image and characterize lithofacies at reservoir zones of interest. Free software dgb earth sciences innovative seismic. The acquisition system used to collect the seismic data presented in this report, may have added 6 ms to the top of each seismic trace. Since the new mining act came into force in 2003, prestack data must also be. The prestack gathers are only about 6 gbytes, making it an excellent dataset for training and demonstrations. Vista desktop seismic data processing software provides data processing from earlystage acquisition qc to final processing and interpretation of 2d and 3d seismic data acquired on land or offshore or as a vertical seismic profile vsp, in all industry and manufacturer data formats. Mar 28, 2018 seismic exploration is an oil exploration method by utilizing seismic information. Typically, a reflection coefficient series from a well within the boundaries of the seismic survey is used to estimate the wavelet phase and frequency. Prestack inversion transforms seismic angle or offset data into pimpedance, simpedance and density volumes through integration of the seismic angleoffset gathers, well data and a basic stratigraphic interpretation. In prestack time migration, we discussed 2d prestack time migration as the rigorous solution to the problem of conflicting dips with different stacking velocities.
To download individual files click on view contents. The reliability of these estimated rock properties at the seismic scale was verified through comparisons between two sets of elastic properties. This is 2d and 3d seismic reflection data from utah forge phase 2c. The seismic data set chosen for this exand fartrace spectra to compensate for the loss of frequency ample is from the norwegian sea and has been reported onwith offset lazaratos and finn, 2004. Seismic exploration is an oil exploration method by utilizing seismic information. Opendtect project with 3d and 2d seismic data, 3d and 2d prestack data, stacking velocities, wells, markers, horizons. All data are final anisotropic, kirchhoff, prestack, time migrated. Conventional, proprietary, software for petrophysical data tends to be expensive to licence, restrictive, slow. All modern seismic inversion methods require seismic data and a wavelet estimated from the data. He has developed software for the seismic processing industry and has specialized in the areas of static analysis, velocity estimation, and seismic migration.
You can use the buttons on the results screen to download or order selected lines and. Prestack visualization and analysis for quantitative seismic. Segyio is an attempt to create an easytouse, embeddable, communityoriented library for. Request pdf a tensor higherorder singular value decomposition for prestack seismic data noise reduction and interpolation a patch of prestack data depends on four spatial dimensions x, y. Only the reprocessed 2d post stack segy and 3d data that forms part of the 2016 oga data can be viewed in iseisview. Estimation of density and other elastic parameters is important in characterizing conventional, unconventional and carbon dioxide co 2 sequestrated reservoirs. Application of crossplot and prestack seismicbased impedance.
Prestack event interpretation uses a true 4d tracker, seeded from gather picks and horizons. Results other researchers rely on a comparison between the near data conditioning. The importance of effective prestack data qc and evaluation cannot be overemphasized. Pdf prestack seismic data analysis with 3d visualization a. Citeseerx 2010, improved resolution in bayesian lithology. A library of matlab code for analysing postmigration prestack seismic data. He continues to develop a fast prestack migration for conventional and converted wave data, prestack migrated statics analysis, and prestack migration of vertical array data. In addition to the developments in all aspects of conventional processing, this twovolume set represents a comprehensive and complete coverage of the modern trends in the seismic industryfrom time to depth, from 3d to 4d, from 4d to 4c, and from isotropy to anisotropy.
In the coming months we will begin to populate this sourceforge project with pure java code for reading and writing prestack seismic data. Seismic facies recognition based on prestack data using deep. Totaldepth is an open source, cross platform, software collection that can process petrophysical data from the oil field such as wireline logs, seismic data and so on. Sparkbased intelligent parameter inversion method for. In recent decades, inversion on the basis of prestack seismic data has gradually become a popular topic in the domain of seismic exploration.
License key protected parts of opendtect opendtect pro and the commercial plugins can be used on this data set without license keys because the software does not check for license key when it runs on this data set. The added dimension of the sourcereceiver offset defines a prestack. All data published is freely available to download where practical from. Normal moveout nmo and stacking of csp gathers is performed to complete the prestack migration process. It is also available as a prestack seismic dataset from the same page 101 gb. Some techniques of using prestack seismic data, will first reduce or compress the size of the prestack seismic data file. Efficient management of prestack seismic data landmark solutions. The prestack seismic data contain a large amount of information, which can reflect the characteristics of the substructure. The readme file containing an explanation of the data including data formats, software that.
Bancroft published in the cseg recorder november 2001 abstract the kinematics of prestack data considers an arbitrary offset between the source and receiver. Tno houses the national geophysical database mainly seismic data. When the reflector geometries that give rise to this problem have a 3d behavior, it is necessary to image the subsurface using 3d prestack time migration. In the approaches to kinematic time migration and demigration presented below the timemigration velocity model is assumed known. Citeseerx prestack imaging of compressed seismic data. Real data are used to validate the application of the proposed inversion method. The focus of our study is lithologyfluid inversion with spatial coupling from prestack seismic amplitude variation with offset avo data and well observations. Therefore, we are increasingly inclined to use prestack seismic data for seis mic facies recognition. An example 3d plot of a subset of these data and inline and xline displays are below. Of the many processes applied to seismic data, seismic migration is the one most directly associated with the notion of imaging.
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