Seismic migration is the process by which seismic events are geometrically relocated in either space or time to the location the event occurred in the subsurface rather than the location that it was recorded at the surface, thereby creating a more accurate image of the subsurface. Models the kinematic solutions used in seismic migration are relatively straightforward to derive or estimate, and are independent of the type of models used. A simplified conceptual basis is 1 the superposition principle, 2 pythagoras theorem, and 3 a subtle and amazing analogy called the exploding reflector concept. Seismic unix su is a public domain seismic processing software package written and maintained by the center for wave phenomena at the colorado school. In seismic imaging, kirchhoff migration has been practised for decades and has an edge due to its adaptability and relative computational speed. This process is necessary to overcome the limitations of geophysical methods imposed by areas of. Kirchhoff migration migration is the basic image making process in reflection seismology. These imaging methods discussed are all applicable to large 3d seismic marine.
Seismic unix, java language, interactive processing, data. Rock properties inversion with kirchhoff ava migration inversion jiang feng and m. A reader with the necessary computer equipment a powerful unix workstation. It is based on diffraction summation approach, which can efficiently handle irregularities in the data in comparison to other wave equation based migrations schneider, 1978. These unique algorithms will be compared to the seismic unix processing methods for both quality and runtime using 2d data. Next, open a terminal window and type the following dialog.
The survey was acquired using a variabledepth towedstreamer. Complete listing of cwp free program selfdocumentations. It is particularly attractive due to its speed and targetoriented capability, which enable efficient velocity model building and updating. This page is intended to be a generic workflow for how to manually install seismic unix from source on windows using cygiwn. Lowrank seismic wave extrapolation on a staggered grid fang, fomel, du, and hu xjtuprimer.
It allows time and depth migration methods to be incorporated within a single basic program, facilitates targetoriented migration, and enables straightforward migration velocity analysis. This book rests on a foundation of science and software provided by many talented re. Parallel 3d prestack depth migration using recursive. Seismic unix has programs for performing many of the operations of geophysical signal processing. Diffraction stacking or kirchhoff migration produces one migrated sample at a time by. Additionally, the method constitutes an essential procedural step for migration velocity analysis as described in migration velocity analysis. Applications of singleiteration kirchhoff leastsquares migration offshore gabon data example we demonstrate the singleiteration leastsquares migration scheme on a 3d marine seismic data set acquired in the deepwater part of the south gabon basin. The first command produces the kirchhoff migration shown in figure 14 and the second command produces the phase shift migration which is not shown. Beammigration methods efficiently extend the benefits of kirchhoff migration and. Kirchhoff depth migration of 3d poststackprestack data sukdsyn2d kirchhoff depth synthesis of 2d seismic data from a. The kinematics of 3d prestack time migration can be formulated as an extension of the kinematics of 2d prestack time migration migration velocity analysis and e. Applications of singleiteration kirchhoff leastsquares. Migration and inversion inversion here means amplitude preserving migration post stack migration f,k stolt vt migration sustolt stolt migration for stacked data or commonoffset gathers gazdag, phase shift gazdag with q sugazmig su version of jeno gazdags phaseshift migration for zerooffset data, with attenuation q. We combine the lbfgs method with leastsquares prestack kirchhoff depth migration.
It allows time and depth migration methods to be incorporated within a single basic program, facilitates targetoriented migration, and enables straightforward migration. Kirchhoff prestack depth migration is one of the most commonly used tools for processing seismic data. Wave equation versus kirchho prestack depth migration of obc data b. Kirchhoff migration, demigration and seismic modeling by demigration. For example vertical or steeply dipping interfaces as well as lower parts of a tendon duct are normally not visible in saft images figure 1.
Todays seismic processing centers need a broad portfolio. Time migration seimax technologies brings a wide range of expertise, technology and innovation to provide the best available time migration services in the industry. Kirchhoff depth migration of 2d poststackprestack data sukdmig2d infile outfile parameters sukdsyn2d kirchhoff depth synthesis of 2d seismic data from a migrated seismic section sukdsyn2d infile outfile parameters sumigps migration by phase shift with. One is by kirchhoff s migration using geometrical approach and other one is fk migration algorithms with fourier transform. 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. Kirchhoff migrations fast, accurate subsurface imaging and efficient velocity model building.
X windows display of encapsulated postscript as a single bitmap. This notion abstract migration of seismic data is the process that attempts to build an image of the earths interior from recorded field data, by. The society of exploration geophysicists the gas research institute. A visual relationship between kirchhoff migration and. A numerical tour of wave propagation yang moved rsfuspdata to datafreeuspland and added elevation. Sacchi, university of alberta, edmonton, canada abstract this paper proposes a strategy to perform amplitude versus angle ava and rock properties inversion simultaneously by applying. Source code for this algorithm is taken form seismic unix su. There are more than 100 modules allowing all usual steps of seismic.
To address this issue, anisotropic pre stack depth migration using kirchhoff method. The kirchhoff migration is the most commonly used migration for depth and time imaging. Examples presented in course materials use seismic unix, madagascar, and trip soft. Downloads are available as either unix gzipped tar files or windows zip files. Introduction kirchhoff migration has been the workhorse of prestack seismic imaging for over a decade. The kirchhoff migration, the most commonly used migration for depth processing, is particularly attractive due to its. Matlab seismic toolbox, seismic unix, usp, and promax. It estimates travel times from a velocity model using ray tracing method, so velocity model is required with this method. The results show that the introduced method can effectively obtain reflectivity model and has a faster convergence rate with two comparison gradient methods.
Center for wave phenomena colorado school of mines golden, co 80401, usa past support was received from. Kirchhoff migration, demigration and seismic modeling by demigration matthias riede on. Kirchhoff migration maximizes efficiency and flexibility. Multifold seismic reflection data from the dixie valley geothermal field in nevada were reprocessed using a nonlinear optimization scheme called simulated annealing to model subsurface acoustic velocities, followed by a prestack kirchhoff migration to produce accurate and detailed depthmigrated images of subsurface structure. The resulting kirchhoff migration algorithms will be applied to model data sets to validate the migration quality and computational effort. The seismic data was reprocessed for pre stack time migration, to get a realistic sub surface picture of the area but the pseudo structures, caused by velocity anomalies, could not be resolved. My confusion, is rtm and kirchoffs prestack time migration are both same how many types of rtm algorithms are available. The seismic unix project is partially funded by the society of exploration geophysicists seg, and by the center for. Seismic migration based on ray methods such as kirchhoff gray and may,1994 1, bevc, 1997 2 and gaussian beam method gray, 2005 3 is a popular imaging method corresponding author. This research uses marmousi data set to determine the most appropriate method of migration. Recent developments of the saft technique as phase evaluation have resulted in improved.
After we see this analogy well look at the most basic migration method, the kirchhoff. Kirchhoff wavefront migration for efficient and accurate imaging 3d prestack depth migrations support multiple imaging. Nevertheless, stolts method can be used efficiently to perform a constantvelocity migration as the first step in a residual migration scheme frequencywavenumber migration in practice. Kirchhoff migration, demigration and seismic modeling by. Participants used their own laptops and software to create a tutorial during the workshop. Here are the guidelines for geophysical software and algorithms papers. The kirchhoff data used the final stacking velocity. Professional individual with highlevel knowledge of mathematics, physics, geophysics, and computer science.
Kirchhoff and fk migration to focus ground penetrating. In addition, we plan to run the migration algorithm in a standard seismic processing environment such as seismic unix, usp or promax. Complete listing of cwp free program selfdocumentations generated by gendocs, a shell script by john stockwell. The seismic unix project is partially funded by the society of exploration geophysicists seg, and by the center for wave phenomena cwp, department of geophysical engineering, colorado school of mines. This paper aims at getting better resolution by applying two migration algorithms. It is efficient to image steep dips with turning waves. Ground penetrating radar gpr based land mine detection has a main challenge of having an accurate image analysis method that is capable of reducing false alarms. However this image analysis depends on having sufficient spatial resolution in the backscattered signal. It is possible to use it to manipulate and create your own seismograms, and also to convert them between the su standard file and the industry standard seg y. Sign in sign up instantly share code, notes, and snippets. Tsunami 2d3d kirchhoff migrations taking your seismic. This is a list of free and opensource software for geophysical data processing and interpretation. Anisotropic kirchhoffs prestack depth migration a case. In prestack time migration, we discussed 2d prestack time migration as the rigorous solution to the problem of conflicting dips with different stacking velocities.
Seismic unix has programs for performing many of the operations of. Here you can find a list of the programs that the su package has, with a brief description and a link to its help page. Imagine that you have a seismic survey which corresponds to the geometry and prop. To facilitate this, an application framework was developed consisting of a. Need help on reverse time migration geophysics forum. I am currently looking into open source project seismic unix, let me know what is the binary for rtm in seismic unix to run some samples. Our amplitude and frequency preserving kirchhoff prestack time migration operates quickly and efficiently to provide superior imaging capabilities in various geological settings. Herman jaramillos personal website, powered by workfolio. Rock properties inversion with kirchhoff ava migration. Wave equation versus kirchhoff prestack depth migration of. Demigration is a seismic forward modeling scheme based on seismic imaging. However, kirchhoff migration is also able to handle the amplituderelated aspects of wave propagation, thus allowing to assign physically sound amplitude values to reflector images. These steps, however, should be improved because some mistakes on details may be present. Demigration itself can be defined as the inverse of true amplitude migration.
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