Strange but true stories of synthetic seismograms cseg. Crains petrophysical handbook synthetic seismograms. Users manual for ray84r83plt interactive twodimensional. Metasim generate synthetic reads collections, help you generate collections of synthetic reads that reflect the diverse taxonomical composition of typical metagenome data sets. A synthetic seismogram is the fundamental link between well data and seismic data, and it is the main tool along with a vertical seismic profile vsp, if available that allows geological picks to be associated with reflections in the seismic data. Global synthetic seismograms using a 2d finitedifference. Download the latest version of adobe reader, free of charge. Tyler schwenk, richard miller, julian ivanov, kansas geological survey, the university of kansas. In this article, we address an important question about correlation of synthetic seismograms with converted wave ps seismic data. Manage account manage email alerts help get adobe reader. An artificial seismic reflection record manufactured by assuming that a particular waveform travels through an assumed model.
Synthetic seismogram calculation using the reflectivity. This feature is removed nicely by performing the convolution operation, which results in the point source waveform shapes. Redcolored traces are synthetic displacements using the wholespace solution multiplied by 2 to account for the freesurface e. Synthetic seismograms and seismic waveform modeling. This example was created from digitized log data in synth and is displayed using one of the many available display templates. The exact formulation of generalized ray theory computations of synthetic seismograms for realistic earth models is relatively complex and expensive. Global synthetic seismograms using a 2d finitedifference method. Rapid processing of synthetic seismograms using windows azure.
Geotools synthetic seismogram, software, geophysical. Quick and easy generation of synthetic seismograms. Synthetic seismogram an overview sciencedirect topics. A synthetic seismogram is the result of forward modelling the seismic response of an input earth model, which is defined in terms of 1d, 2d or 3d variations in physical properties. Keywords reciprocity synthetic seismogram cloud computing windows azure 1 introduction seismic waves generated by natural andor manmade seismic sources propagate through the interior of the earth and cause motions of the ground. A cloudbased synthetic seismogram generator implemented. Droxler3 abstract onedimensional synthetic seismograms are constructed from velocity and density measurements taken during ocean drilling program odp leg 165 at sites 998, and 1001. The production process of synthetic seismogram is a complicated, multiple factors should be considered to make high quality synthetic seismogram, because these factors are intertwined, some even contain each other, restrict the synthetic. Synthetic seismograms and seismic waveform modeling lupei zhu saint louis university 2011. Below is a 2d plot of the 11layer halfspace model used to generate the synthetic seismogram.
Synthetic seismograms were also created using this second velocity profile as well. Generates a synthetic seismogram for a simple 1d layered. Synthetic seismogram modeling contact ihrdc sales for corporate purchases add to cart price. The use of edited or modeled log data as input is highly recommended. Synthetic seismogram computation by expansion in generalized rays ralph a. A ps synthetic elastic gather generated from the pvelocity, svelocity and density curves is shown in d.
In order to study seismic wave propagation through laterally varying sea floor structures, a software package has been created to generate synthetic seismograms by finite differences. The result of one of many forms of forward modeling to predict the seismic response of the earth. How could i generate synthetic seismograms of surface waves. The computation of theoretical seismograms for models in which the elastic parameters and density vary only with depth in a plane, cylindrical or sph. Synthetic seismic model zaid almusallam sage 2004 outline objective definition reflection data synthetic model comparison conclusion objective determine the thickness of the basalt layer synthetic seismograms defn an artificial seismic reflection record manufactured by assuming that a particular waveform travels through an assumed model a 1d sythetic seismogram is. A synthetic seismogram is created to simulate seismic data acquisition in your computer. Synthetic seismic model zaid almusallam sage 2004 outline objective definition reflection data synthetic model comparison conclusion objective determine the thickness of the basalt layer synthetic seismograms defn an artificial seismic reflection record manufactured by assuming that a particular waveform travels through an assumed model a 1d sythetic seismogram is formed by. You have to define all the steps you want first, irrespective of what language you code it in and that is well outside of the scope of a matlab forum if you havent done it already. Synthetic seismogram of well os1 track 1 is the gamma ray lithology log, track 2 represents the standard synthetic seismogram while track 3 shows the combined spliced pseudo synthetic seismogram all the reservoirs delineated in well os2 were oil saturated. Synthetic seismic profile plot the kansas geological survey. As seen in figure 10, a fairer general correlation was observed in these zones. For more details regarding how to download the synthetics from iris, visit the shakemovie synthetics detail page links to tarballs with the 1d and 3d synthetics in their native sac format from the shakemovie website are given. After integration of the raw 2d synthetic velocity seismogram, we obtain the displacement seismogram, which contains longperiod tails associated with its line source nature.
Synthetic seismogram computation by expansion in generalized. In hydrocarbon exploration this is used to provide a tie between changes in rock properties in a borehole and seismic reflection data at the same location. Our product is widely used in the exploration community in support of prospect development and evaluation. Synthetic seismogram studies have spanned many decades from the earlier days of 1d modeling as described by robinson and treitel 1980 to the more recent descriptions of finitedifference anisotropic viscoelastic modeling as described by carcione 2007. Because simple synthetic seismograms assume vertical incidence, zerooffset, avo effects are not considered. This trace closely approximates a trace from a seismic line that passes close to the well in which the logs were. A cloudbased synthetic seismogram generator implemented using windows azure article pdf available in earthquake science 265. Rapid processing of synthetic seismograms using windows azure cloud.
The unknown physical properties of the earth beneath a seismic survey are known properties at a wellbore pwave acoustic velocity and bulk density. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. This feature allows you to import other plots or company logos into your synthetic seismogram plot. Flow chart for calculating seismograms starting from the frequency domain formulation of a seismogram u w,p,zsummary of synthetic seismogram methods. Version 11 is very similar to version 10 with enhancements to work with the miniseis iii. To cite the source or reference the use of a particular synthetic seismogram. Generating pseudosynthetic seismogram with resistivity. Flow chart for calculating seismograms starting from the frequency domain formulation of a seismogram u w,p,z. Velocity data from the sonic log and the density log, if available are used to create a synthetic seismic trace. The output is a synthetic seismogram that contains the reflectivity function filtered by the. A typical synthetic seismogram is given below as well as a geologic cross section from logs.
This course introduces the techniques used in forward modeling the acoustic properties of the earth to predict the seismic response of the earth. The reflection coefficients for the trace were simply computed with the recursion. Generating a synthetic seismogram can be a very complicated process. Compute complete synthetic seismograms based on the following required elements. Computation of rays, travel times, ray amplitudes and ray synthetic seismograms in 3d laterally varying structures with isotropic andor generally anisotropic layers. As discussed, if a vsp is available for a particular well, a synthetic is not needed. For more details regarding how to download the synthetics from iris, visit the shakemovie synthetics detail pagelinks to tarballs with the 1d and 3d synthetics in their native sac format from the shakemovie website are given. Modal surface wave and finite difference and finite element methods not included basic equation for a synthetic seismogram ut, x 1, x 2. This second synthetic seismogram did not tie well with the scs profile at site 1001, and resulted in synthetic horizons that appear significantly shallower in the synthetic than in the seismic data.
A linear filter model of the complicated seismic process can be formulated by assuming that 1 the layering of the earth is described by the continuous velocity log, 2 the shot pulse is timeinvariant and propagates as a plane wave with normal incidence, and 3 all multiples, ghosts, and other noise are negligible. Over the last few years, several articles on multicomponent seismic data have appeared in geophysical corner describing various aspects of processing and interpretation of such data. Synthetic seismogram service reference materials sac output file names ax2d. The synthetic seismogram is generated by convolving the reflectivity. A real seismic gather at the location of the well is shown in e. The iris dmc archives and distributes synthetic seismograms from the the global shakemovie project. Synthetic seismograms and multichannel analysis of surface. Strange but true stories of synthetic seismograms cseg recorder. This web application is a well profile presentation of the well data plotted against acoustic travel time in millisec with synthetic seismic plot tracks.
Synthetic seismogram calculation using the reflectivity method. Steve sloan, jason mckenna us army corps of engineers. Computer programs in seismology overview model96 gprep96 genray96 gpulse96 generalized ray hprep96 hspec96 hpulse96 file96 wa v enumber integration hprep96p hspec96p hpulse96 pt cprep96 cseis96 cpulse96 asymptotic ray theory ray sprep96 sdisp96 slegn96 sregn96 spulse96 modal summation fig. As ps reflectivity is a function of the angle of incidence, and the amplitude information on the nearoffset traces is not optimum, in practice ps synthetic seismograms are computed over a range of angles usually 10 to 25 degrees, with each correlated with the ps stack data.
This example was created from digitized log data in synth and is displayed using one of. Dispersion interpretation from synthetic seismograms and multichannel analysis of surface waves masw j. Based on a database of given genomes, the software allows the user to. Users manual for ray84r83plt interactive twodimensional raytracingsynthetic seismogram package. The results of pp and ps correlation for the well x are shown in fig 9 and fig 10 respectively. The elastic wave equation can be solved in two dimensions either for point sources in cylindrical coordinates or for line sources in rectangular coordinates.
The synthetic seismogram is generated by convolving the reflectivity derived from digitized acoustic and density logs with the wavelet. Synthetic seismogram from the sonic log, assuming constant density, normal incidence, no multiples or reverberations and no absorption, a synthetic seismic trace was created. Research to improve the quality of synthetic seismogram. Three different synthetic seismograms created with identical well logs and wavelets figure 6 should theoretically be identical, however we observe that the first two traces are reasonably similar but the third trace, the one that uses flow b, is quite different. The synthetic seismogram often called simply the synthetic is the.
Create synthetic seismograms for a 1d layered model. I made synthetic of surface wave by herrmann package but could not get desired answer. Generates a synthetic seismogram for a simple 1d layered model. A more narrow definition used by seismic interpreters is that a synthetic seismogram, commonly called a synthetic, is a direct onedimensional model of acoustic energy traveling through the layers of the earth. The seismic model, synthetic section, and real seismic section follows. Synthetic seismograms, synthetic sonic logs and synthetic. Synthetic seismogram free synthetic seismogram software.
This web application requires sonic log curve data. The ps synthetic seismogram blue generated from the svelocity and the pseudo density curves is shown in b and with ps seismic data in c. The basement high and surrounding basal sand are the key elements in this model. Rapid processing of synthetic seismograms using windows. Also, there is usually a considerable difference between the synthetic and the real data due to sampling area. The wellbased data will sample a cylinder less than a meter in radius from the. Software to download institute of geophysics of the cas, v. Dispersion interpretation from synthetic seismograms and. This program will read a model, the distance file, and get source and receiver depth. The synthetic seismogram is a seismic trace that has been contructed from well log data. The expense can be reduced considerably by a proper organization of the computational procedures. Synthetic seismograms are the main tools in modelling the complexities in the seismic body. Synthetic seismograms are then computed by the modal summation technique for sites placed at the nodes of a grid with a step of 0.
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