Ray tracing software seismic wave

The traditional way of showing seismic wave propagation, by geometrically tracing waves through the earth. A wide range of free software and commercial software is available for producing these images. The method used for modeling is the ray tracing to wave front construction. Accompanied by a package called zplot for interactive plotting and picking of 2d and 3d wideangle seismic. For complex geology or caving environments, 3d raytracing using a. Surface wave ray tracing and azimuthal anisotropy 571 if the tensors. Various areas of application have been established and new ones are under development.

Refraction waves forward modeling and inversion in arbitrary layered medium, 3. A practical introduction to ray tracing 3d graphics for readers not familiar with graphics by paul rademacher although threedimensional computer graphics have been around for many decades, there has been a surge of general interest towards the field in the last couple of years. Ray tracing is a technique that can generate near photorealistic computer images. Gathering only the feasible rays within the seismic box, the resulting ray tracing is presented in fig. Improved applicability of ray tracing in seismic acquisition. If an interface is located within an anisotropic media, then up to three reflected. To verify the robustness of the presented algorithm, we apply our ray tracing method to model real wideangle p wave reflection data collected from an area located at the zagros thrust belt zone in the southwest part of iran. Ray trace modeling for survey designing, seismic imaging. One section represents a synthetic stacked seismic section created using normal incidence ray tracing, while the second represents a synthetic migrated section created using image ray tracing. Ray tracing modeling and inversion of light intensity. Seismic ray tracing is often used to get information about the earths interior. Ludek klimes, michal kvasnicka, 3d network ray tracing, geophysical journal international, volume 116, issue 3. The 3d ray tracing tool is multithreaded allowing for more rapid calculation of 3d paths and travel times by spreading the job across all available computer processors. Ray tracing of turning wave in elliptically anisotropic media.

Seismic modeling software available at cgiss the follow table lists the available software for modeling seismic data. Ray tracing of a beam of light passing through a medium with changing refractive index. Advanced analysis modules in the software enable you to examine geometry effects, analyze geometry artifacts, generate synthetics, and build. Improved applicability of ray tracing in seismic acquisition, imaging, and interpretation. Traveltimes and raypaths of first arrival seismic waves. An efficient sequential algorithm for ray tracing is being developed by the research group of dr. This method has the advantage of directly showing the paths of individual parts of the wave front, but the disadvantage of not showing the amplitudes or what the wave would actually look like at any given time. Trusted to solve the industrys most complex challenges, the delfi environment is supported by the collective knowledge of the worlds largest body of. In seismology, geophysicists use ray tracing to aid in earthquake location and tomographic reconstruction of the earths interior. The results are iteratively updated to reduce the discrepancies between the observed and calculated reflection times. Ray tracing equations in transversely isotropic media with. For the love of physics walter lewin may 16, 2011 duration. Ray tracing in practice introduction although 1d whole earth models are an acceptable approximation in some applications, lateral heterogeneity is signi.

The list is split into broad categories, depending on the intended use of the software and its scope of functions. The two ray equations are equivalent to the two hamilton equations. Is there any software or codes for modeling the seismic wave. Ray tracing algorithm for oneway traveltime calculation in passive seismic or microseismic applications.

Swag,seismic wave analysis group,swag at kaust university,academic. At its heart, the delfi environment utilizes powerful software built on deep science to automate and accelerate complex functions such as modeling, simulation, analysis, and forecasting. Numerical ray tracing is a procedure that makes use of these equations in order to advance the wave along the ray by an incremented. In physics, ray tracing is a method for calculating the path of waves or particles through a system with regions of varying propagation velocity, absorption characteristics, and reflecting surfaces. Much software is in seisunx from the center for wave phenomena at colorado shool of mines. It contains 16 standalone applications handling the full range of seismic exploration methods from reflection, refraction, and surface wave to borehole seismic. Considerable attention is devoted to ray tracing and dynamic ray tracing of s waves in heterogeneous anisotropic media, to the coupling ray theory for s waves in such media, to the summation of gaussian beams and packets, and to the selection of models suitable for ray. Software for 3d seismic data processing and inversion. Seismic waves and snells law a wave front is a surface connecting all points of equal travel time from the source. Many of these applications require a modelling system with flexible, robust and efficient modelling algorithms in the core.

Omni 3d software delivers fully optimized designs for land, marine, transition zone, vertical seismic profile vsp, and multicomponent surveys. An overview of depth imaging in exploration geophysics john etgen1, samuel h. The tomography must then iterate to converge to the best estimate of the true model by minimizing the differences between the observed and predicted traveltimes. You will find it helpful to use subroutine layerxt provided in fortran in appendix d and in the supplemental web material as a matlab script, which gives dx and dt as. The objective of modeling is to determine if there is a noticeable difference between the seismic signature of the tight carbonate and that of the.

While the mathematical description of the wavefronts is rather complex, that of the rays is simple. Ray tracing physics project gutenberg selfpublishing. Elastic wave equation modeling, however, accounts for direct waves, primary and multiplereflection waves, converted waves, head waves, as well as diffraction waves. Raytracing algorithm for oneway traveltime calculation in passive seismic or microseismic applications. If all ray tracing steps are done fully in a 3d sense, then a very reliable velocity model is obtained.

Application of turning ray tomography to hussar 2d seismic line from central alberta algorithm traces rays through a starting model and computes predicted traveltimes using 1. This is due to the fact that one of the main problems in. Ray trace modeling for survey designing, seismic imaging and. Opensource software seismic wave analysis group swag. An overview of depth imaging in exploration geophysics. We use helmholtz theorem in order to represent u in terms of a curlfree scalar potential. Visualizing seismic waves for teaching and research. Notice that free and opensource requires that the source code is available. The equation gp,x 1 will give us the magnitude of the phase velocity v as a function of the vti medium parameters v0. Maswremi surface waves data processing and interpretation, 2. Zondst3d is designed for threedimensional interpretation of seismic tomography data on refracted waves land, crossborehole and water variants in geophysics, the term seismic tomography is known for a long time. The simplest one is the 1d model with a vertical sequence of constant material properties separated by plane, horizontal layers.

Quadraticlinear travel time interpolation of seismic raytracing. Sh and sv seismic waves together with polarities of p waves into the mechanism. Ray tracing solves the problem by repeatedly advancing idealized narrow beams called. The student should be familiar with the key concepts of seismic survey design, acquisition, and processing. This method has the advantage of directly showing the paths of individual parts of the wave front, but the disadvantage of not showing the amplitudes or what the wave. Avo modeling in seismic processing and interpretation ii.

The method is normally used to map bedrock topography, delineate seismic velocities of subsuface materials and to assess rock rippability. Spectra of seismic waves can be analysed to detect noise and adaptively remove it. Aug 11, 2012 seismic ray tracing software post by mohamed sat aug 11, 2012 9. Seismic ray tracing and wavefront tracking in laterally. Omni 3d seismic survey design software helps you create optimal 2d and 3d designs for land, marine, oceanbottom cable obc, transition zone, vertical seismic profile vsp, and multicomponent surveys. First arrival time of p wave is analysed to define seismic velocity distribution. When integrated with the ims visualisation software, 3d visualisation options become. Nov 16, 2017 seismic ray tracing in anisotropic media with irregular surface is crucial for the exploration of the fine crustal structure. Refraction timedistance plots the ray tracing algorithm in surface seismic surveys the point source is located on the surface and detectors of the resulting seismic waves are located on the surface. Solution of forward problem basis on special ray tracing algorithm of graph theory shortest. Different model representations have been developed for seismic ray tracing.

We have verified our methods traveltimes and amplitudes against the norsar ray tracing software. Its objective is to build a global seismic wave velocity model of the earth interior. Seismic ray tracing and wavefront tracking in laterally heterogeneous media n. Software products the core applications for norsar seismic modelling packages are 2d and 3d seismic ray modelling, survey planning, time lapse studies, reservoir analysis, and greens functions for psdm. It is shown that the general effect of deformational mean flow over long time periods is to shorten the wavelength, the effect being most pronounced for waves of modest spatial scale. Sambridge research school of earth sciences, australian national university, canberra act 0200, australia 1 introduction 1. Light propagation is similar in both nature and theory to seismic wave propagation in the subsurface. An alternative approach to ray tracing, which makes use of the eikonal equation, leads to two ray equations. Dynamic ray tracing and its application in triangulated media. Throughout the last twenty years, 3d seismic ray modelling has developed from a research tool to a more operational tool that has gained growing interest in the petroleum industry. Usually, this medium can be described by only the vertical phase velocity and the horizontal phase velocity for seismic wave propagation.

Ray tracing in laterally heterogeneous media is nontrivial. The ray is advanced by a small amount, and then the direction is recalculated. This is a sister package providing same functions with the python3 package psraytrace shooting the core function of raytracing algorithm, actually a 2d algorithm. There are also utilities for vibroseis correlation and wavefield modeling. Norsar 3d is a software for seismic modeling in three dimensions. Accompanied by a package called zplot for interactive plotting and picking of 2d and 3d wideangle seismic data. Seismic ray article about seismic ray by the free dictionary.

In order to improve the accuracy of existing methods, huge quantities of information must be computed. Dynamic ray tracing and traveltime corrections for global. Introduction one of the main domains in geophysics concerns seismic tomography. Write a computer program to trace rays through this model and produce a p wave tx curve, using 100 values of the ray parameter p equally spaced between 0. The seisunx software is easy to use within their system. To model the seismic wave propagation in random media, what software or. In addition, ray tracing can test the effects of variation in critical survey parameters on subsurface imaging.

Seismic survey design software robust survey design and analysis software omni 3d seismic survey design software is the industry standard for seismic survey acquisition design, modeling, and analysis. The shortest path method for seismic ray tracing in complicated media, phd thesis, institute of geophys. Studies of wave propagation in plasmas using ray tracing method can be found in. Ray tracing of seismic waves through the mesh of triangles is then particularly efficient because ray paths know which triangle they are entering when they leave a previous one,more. Application of turningray tomography to hussar 2d seismic. Contribute to shuleyuseismic raytracing development by creating an account on github.

Ray tracing and amplitude calculation in anisotropic. Iterative updating of the model is needed to refine the velocity distribution. It overcomes the shortcomings of the ray tracing approach that breaks down in many cases such as at the edges where the calculated amplitude is infinite or in the shadow zones. Elliptically anisotropic medium is the type of anisotropic media with only four independent elastic parameters. Software to download institute of geophysics of the cas, v. Gray2, and yu zhang3 abstract prestack depth migration is the most glamorous step of seismic processing because it transforms mere data into an image, and that image is considered to be an accurate structuraldescriptionoftheearth. Zondst2d is designed for twodimensional interpretation of seismic tomography data on refracted and reflected waves land, crossborehole and water variants. Rays are the normals to the wavefronts, and they point in the direction of the wave propagation. The intent is that users of the code will provide extra programming for features such as distributed ray tracing, path tracing, photon mapping, radiosity, etc. This is a list of free and opensource software for geophysical data processing and interpretation. In spite of this drawback the ray tracing migration processing does improve the quality and interpretability of the seismic data considerably. This ray tracing method is the only migration technique to give. Ray tracing through a 1d velocity model institute of. The latter one is implemented according to the simplex raytracing technique.

It has its applications in a number of areas in geosciences including oil exploration and quake fault analysis. It is not surprising to see a large number of common problems. Ray tracing and amplitude calculation in anisotropic layered. New seismic modelling facilities in matlab crewes research report s volume 12 2000. We present in this paper the design of a software program implementing a fast seismic raytracing in an earth mesh. Ray tracing migration uses a model of the subsurface to carry out the ray tracing exercise. Ray tracing modeling and inversion of light intensity under a water surface abdullah al theyab. Besides improving the applicability of standard ray tracing, the purpose is effective software design. Seismic ray tracing using evolutionary programming. Seismic wave velocity varies within and beneath earths crust, causing these waves to bend and reflect.

Ray tracing equations in transversely isotropic media cosmin. Seismic raytracing and earth mesh modeling on various. Gibson of the department geology and geophysics at. Rayinvr, package that does 2d ray tracing, traveltime inversion, amplitude. The advantage with ray tracing is that it is less time consuming flexible and relatively less expensive technology compared to full wave equation modeling. Ray tracing equations in transversely isotropic media. Ray tracing works by assuming that the particle or wave can be modeled as a large number of very narrow beams rays, and that there exists some distance, possibly very small. Using the same source point and changing the ray code through the command line echo 7 2 2 2 2 2 1 0 path. General relativity edit in general relativity, where gravitational lensing can occur, the geodesics of the light rays receiving at the observer are integrated backwards in time until they hit the region of interest.

In modern theoretical seismology, there is a need to compute seismic wave fields in. Accurate ray tracing using real earth model properties rather than effective parameters is a key requirement for achieving accuracy over the wide angles. In other words, the provided ray tracing software is not a complete finished product, but rather is a set of lowlevel tools. Ray tracing may be used to compute paths through a geophysical model, following them back to their source, such as an earthquake, or deducing the. We calculate the ray path and traveltimes of seismic wave with vector ray tracing, and develop a method to reconstruct the velocity image of acoustic media from direct traveltimes of crosshole data. Review of ray theory applications in modelling and imaging. The technique performs a direct nonlinear inversion of p wave reflection travel times in layered vti media to produce interval shortspread moveout velocity vpn and horizontal velocity vpx. An improved raytracing method called quadraticlinear travel time interpolation qlti was developed based on the linear travel time interpolation lti method given by asakawa to increase seismic travel time measurement accuracy. The code can compute 3d ray paths and multipaths in complex media for a variety of common p and s wave phases p, pg, pn, pcp, pp, pp, pmp, s, ss, scs, sks, ss, etc.