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Y2   @` @ ` @ @@@`@@@@@` `@``````` @` @` @` @`@ @@@`@@@@@ @ @@ @` @ @ @ @ @@@ @@@`@@@@@@@@@@`@ `@@`@``@`@`@`@`@@ @@@`@@@@@@ @@@`@@@@@@ @@@`@@@@@@ @@@`@@@@@ @` @ ` @ @@@`@@@@@` `@``````` @` @`ࠀ @` @` @` @ ` @ @@@`@@@@@` `@```````׀ @` @` @` @`452C ( ]]]]9ShSh BhBzBzBzzhzzzzh9 zzzSzzzhhS99  Szz'9 z'zhz Sz'z 9']]]]]4+lpaT  n   @` @ ` @ @@@`@@@@@` `@``````` @` @` @` @`@ @@@`@@@@@ @ @@ @` @ @ @ @ @@@ @@@`@@@@@@@@@@`@ `@@`@``@`@`@`@`@@ @@@`@@@@@@ @@@`@@@@@@ @@@`@@@@@@ @@@`@@@@@ @` @ ` @ @@@`@@@@@` `@``````` @` @`ࠀ @` @` @` @ ` @ @@@`@@@@@` `@```````׀ @` @` @` @`45nC (WWWW0ShSh9h9z9z9zzhzz zz h9 zz z Szz z hhS 99 Szz*9 z* zhz Sz* z 9*WWW4+lpaT  n   @` @ ` @ @@@`@@@@@` `@``````` @` @` @` @`@ @@@`@@@@@ @ @@ @` @ @ @ @ @@@ @@@`@@@@@@@@@@`@ `@@`@``@`@`@`@`@@ @@@`@@@@@@ @@@`@@@@@@ @@@`@@@@@@ @@@`@@@@@ @` @ ` @ @@@`@@@@@` `@``````` @` @`ࠀ @` @` @` @ ` @ @@@`@@@@@` `@```````׀ @` @` @` @`45nC (WWWW0ShSh9h9z9z9zzhzz zz h9 zz z Szz z hhS 99 Szz*9 z* zhz Sz* z 9*WWW$l!XGRayfract online helpN 'lCopyright Intelligent Resources Inc. 1996-2007. All rights reserved. See rayfract.com for tutorials etc.BrowseButtons()ZmainRayfract online helpZspreadsRayfract receiver spreadsHaZasciformASCII format dialogaZprocessRayfract processing sequenceaZfctkeysRayfract keyboard mappingaZcntxthlpRayfract help)  RAYFRACT.CNT ,F= = I1 f-I{zIntroduction2 {# IntroductionvI4C TRAYFRACT is a Windows 32-bit software package, suited for processing of seismic profiles with low, medium or high coverage. We support the interpretation of both P-wave and S-wave seismic refraction surveys. First breaks are imported via ASCII, or picked semi-automatically or interactively. Traveltimes may be mapped to refractors manually or semi-automatically, based on apparent (instantaneous) CMP velocities measured and typical refractor velocity intervals, as specified by the interpreter. Finally, traveltime data is processed on a per refractor basis, according to three different interpretation methods: CMP intercept time refraction (Gebrande and Miller 1985; Rhl 1995), Plus-Minus (Hagedoorn 1959) and Wavefront (Brckl 1987; Jones and Jovanovich 1985). Plus-Minus and Wavefront are based on traveltime field regression (Brckl 1987). Wavefront considers local emerging wavefront angles. A critically refracted ray is represented by first break and emergence angle at a receiver. Each reverse ray is combined with a matching forward ray, such that both rays surface from an approximated common refractor location. {1 0cYou may consider our Wavefront method as an optimized version of the GRM (Generalized Reciprocal Method) algorithm as described by Palmer (Palmer, 1980). Instead of assuming a user-specified constant receiver separation ("XY distance", "Optimum XY value") all along the profile, the Wavefront method automatically estimates the local receiver separation at each receiver station, from local forward and reverse wavefront emergence angles. So the receiver separation obtained may vary laterally along the profile considerably. This means that the Wavefront method optimally images refractors with high relief (i.e. strongly undulating refractors, with pronounced troughs and humps).V4l[ ]zOTStarting with version 1.30, as released in December 1998, our software now also implements the Delta-t-V method as described by (Gebrande and Miller 1985). This pseudo-2D turning ray inversion method delivers continuous 1D depth vs. velocity profiles for all profile stations. The profiles are written to an ASCII file which may be processed conveniently with Golden Software's Surfer etc., to produce station nr. vs. depth velocity maps / contour plots with velocity isolines. The method handles real life geological settings such as vertical velocity gradients inside layers / linear increasing of velocity with depth / velocity inversions / pinchouts and outcrops / faults and local velocity anomalies, without requiring user-specified a priori model constraints. Especially, it does not require the user to map traveltimes to refractors at all. Importing seismic data and complementing it with geometry information / traveltime picks is all that is needed. Delta-t-V models show you the relative velocity distribution in the subsurface. Systematic velocity increases (at the top of the basement) and strong velocity anomalies such as low velocity zones, faults etc. will be visible in many situations. The absolute velocity values obtained may have an error of up to about 15 or 20 percent or more, however. Especially, the absolute values, signatures and locations obtained for strong but narrow velocity anomalies may be distorted and should be taken with a grain of salt. Pseudo-2D Delta-t-V generates systematic imaging artefacts in case of strong lateral velocity variation in the near-surface overburden. Use our Smooth inversion method to virtually eliminate these artefacts in the initial model, and to obtain more reliable absolute velocity estimates.ODU x Vs.FStarting with version 2.01, as released in October 2000, RAYFlD RACT now supports improved quality control of depth-velocity models as obtained with our Delta-t-V method by forward modeling of wave propagation through these models. The forward modeling algorithm implemented for modeling of first breaks is the first-order Eikonal solver as described by Podvin/Lecomte (Lecomte 2000). It handles any geological setting such as vertical or lateral velocity gradients, sharp velocity changes (i.e. discontinuous velocity distribution, systematic changes at unit boundaries), strong velocity contrasts (of local velocity anomalies) and velocity inversions and runs very fast. Thanks to this powerful new quality control tool our Delta-t-V method does not require core drilling data any longer. Just check and if necessary tune the Delta-t-V parameters by comparing synthetic i.e. modeled traveltimes with traveltimes as measured and picked (as shown in the Shot breaks display). According to raytracing results from about 20 sample profiles, Delta-t-V does work for low coverage surveys (just 5 or 7 shots per receiver spread) as well. Default values for the Delta-t-V parameters as proposed by the software automatically will give good results in most cases. lG= HH>Starting with version 2.11, as released in February 2001, RAYFRACT now also supports the iterative refining of Delta-t-V output (or of Surfer .GRD velocity models as obtained with third party methods) with our new WET Wavepath Eikonal Traveltime tomography processing. See (Schuster 1993; Watanabe 1999). This highly sophisticated method supports extreme topography. Wave propagation is modeled in a physically meaningful way with wavepaths i.e. Fresnel volumes (also known as "fat rays"), based on our advanced first-order Eikonal solver as mentioned above. As a consequence velocity anomalies such as low velocity zones and faults may be imaged with higher contrast than with conventional ray tomography.BD[JE Xw Starting with version 2.34 as released in March 2002, WET processing allows the integration of uphole picks for seismic traces recorded by surface receivers for shots positioned at the bottom of deep shot holes (e.g. recorded by same receiver spreads as used for surface based shots).Starting with version 2.43 as released in April 2003, RAYFRACT now supports the fully automatic interpretation of 2D profiles with our Delta-t-V and WET inversion methods, including automated gridding, imaging and contouring of resulting tomograms with Golden Software Surfer.GkM1 0TStarting with version 2.51 as released in March 2004, RAYFRACT now implements a fail-safe "Smooth inversion" option, for fully automated determination of a 1D gradient initial model and subsequent refinement with WET tomography processing. A smooth initial 1D gradient model is determined automatically directly from the traveltime data, by averaging Delta-t-V method 1D velocity-depth profiles along the seismic line. This procedure delivers reliable smoothed models even in case of velocity inversions. The 1D initial model guarantees that Delta-t-V artefacts (occurring e.g. in situations of strong refractor curvature / strong lateral velocity variation) are virtually eliminated from the interpretation at an early stage.[JSG \+H3۲For detailed and up-to-date information about features of version 2.61 and later versions of our software seehttp://rayfract.com/help/release_notes.pdf. Version 2.62 of our RAYFRACT software, as released in August 2005, features improved Delta-t-V internal static corrections. During a second pass of statics computation, ray emergence angles are now regarded. See the German language thesis of Roland A. Winkelmann, as available at amazon.de, ISBN 3932965043 , chapter 3.3. Also, we now offer an additional Delta-t-V setting Suppress velocity artefacts to suppress the genekMS ration of processing artefacts, i.e. unrealistic velocity variation.kMq1 0XbVersion 2.71 of our RAYFRACT software, as released in December 2006, now supports modeling of constant-velocity layers in addition to constant velocity-gradient layers, with the XTV inversion method. This method has been published by Roland A. Winkelmann in his 1998 Ph.D. thesis (Winkelmann 1998), as done with Professor Helmut Gebrande in Munich. Professor Gebrande has described the foundations of CMP refraction theory, in (Gebrande and Miller, 1985) and (Gebrande 1986). See alsoXS3 4http://edoc.ub.uni-muenchen.de/archive/00000222/01/Gawlas_Peter.pdf . Describes XTV inversion in chapter 3.2.2.4, page 43 ff.Version 2.73 of our RAYFRACT software as released in May 2007 has been adapted to work under Microsoft Windows Vista, in addition to 98 SE, NT, 2K and XP. Also, we now allow import of OPTIM LLC SeisOpt data files, with first breaks and source/receiver geometry. When importing Interpex GREMIX or OPTIM LLC SeisOpt files, dead traces missing from these files will be regenerated automatically when located in the active part of the specified receiver spread type.qA P㦍AVersion 3.01 of our RAYFRACT software as released in September 2007 now supports crosshole survey interpretation, with our Smooth inversion method and a constant velocity initial model. Data needs to be formatted as Daryl Tweeton GeoTomCG input files. For instructions showing processing of a crosshole data set seehttp://rayfract.com/tutorials/igta13.pdf. Also, we now support import of Geometrics/OYO SeisImager PickWin and PlotRefa .VS formatted files.-B= H]8Version 3.05 released in January 2008 implements an optimized WET inversion algorithm. The wavepath width is determined for each trace individually, as a linear function of the picked traveltime. Uncheck WET Tomo|Adjust wavepath width to use the same wavepath width for all traces. Also, we now use the undifferentiated Ricker wavelet for wavepath modeling and weighting per default, instead of its derivative. You can edit WET parameters with WET Tomo|Interactive WET tomography... .F ڀ RQW1 _جƔu|s.F]|ATVersion 3.06 released in February 2008 scales WET smoothing filter height with depth below topography. This ensures better vertical resolution of the weathering layer. Also, the misfit between modeled and picked first breaks decreases faster during WET inversion (with fewer iterations). Disable this feature by unchecking Smooth invert|Scale WET filter height.Please note that the conventional CMP intercept time refraction method (Ruehl 1995) is not suited for obtaining reliable refractor velocities and depths with highly undulating refractors. The CMP sorted trace display (Midpoint breaks display) is suited for semi-automatically mapping first breaks to refractors even in case of strong refractor relief, however. Advantages of carrying out this semi-automatic mapping over the conventional manual branch points picking in the Shot breaks display are repeatability, consistency, speed. Once this mapping has been carried out, you may process the mapped first breaks with Wavefront and Plus-Minus methods. Especially the Wavefront method delivers reliable results even at the locations of steep refractor synclines and anticlines. For true 2D WET tomography processing of such profiles with strong basement undulations, we recommend to use our Smooth inversion method, based on a 1D gradient initial model.VBM hs.Fu|CIf you prefer to carry out the mapping of first breaks to refractors in a more conventional way, you may do so in the Shot breaks display. This display support s the interactive positioning of branch points on shot sorted traveltime curves. For low coverage data, this is the only option available for mapping first breaks to refractors. Always record your traces with overlapping receiver spreads, optimally by as much as half the spread length. If the basement coverage with first breaks is too discontinuous, traveltime field regression may not converge towards a stable solution.O  / ,AThe Surfer Kriging gridding method sometimes generates artefacts, such as false high velocity anomalies directly below the topography. If you want to experiment with different algorithms than the default Kriging method, please download archivehttp://rayfract.com/common/scripts.zipto a temporary directory e.g. C:\TEMP. Now unzip the archive in C:\TEMP and proceed as described in the included README.TXT. We offer scripts for gridding methods "Natural Neighbor", "Nearest Neighbor", "Delauney Triangulation" and "Minimum Curvature". u  Documentation conventionsThe shorthand notation "Select File|Open" is used for the action of moving the cursor to the File menu, opening it by pressing your left mouse button on it, and finally selecting menu item Open by dragging your mouse down until that item is highlighted, and then releasing your left mouse key. User interface items such as menu items (including above shorthand notation), dialog box titles and section display window types are italicized. Seismic refraction methodology and practical recording / interpretation terms are underlined when referred to in context sensitive help pop up dialogs, as displayed when tabbing to a dialog control and pressing F1. You may search for definitions of these terms in the online help index. Select Help|Search for Help On in order to do so. The RETURN key is used to signify both the ENTER key and the equivalent RETURN key. Hard-disk volume is used interchangeably with hard-disk partition. Expressions receiver spread type, spread type, receiver layout type and layout type are used interchangeably as well. Important statements and terms are printed in bold typeface.O 7 >System requirementsTo use Rayfract, you will need the following :  S tyP:H""""A 386 (or better) PC running Windows 98 (Second Edition recommended), Windows NT 4.0 (with Service Pack 4 or higher applied), Windows 2000, Windows XP or Windows VistaVGA monitor or betterAt least 256 MBytes of RAM. For high coverage / long profiles and efficient WET tomography processing, 1'024 MB or more are recommended.At least 100 MBytes of available hard-disk space for the program files, including two sample profiles.T v=P:H"""Enough hard disk space for your profiles. One profile typically consumes about 20 MBytes of space, depending on data density, profile length and the amount of data generated by our tomography processing and Surfer gridding, smoothing, imaging and contouring of results.Surfer version 8 for automatic plotting of tomograms. You may download a free print-disabled demo from http://www.golden.com. Enter e.g. state CA .After installation of the free Surfer 8 demo, start it up once interactively via the Start menu. Then click on the splash screen. If you omit this step, Rayfract is not able to automatically call Surfer, and will just hang instead.,( P:H5 ) "HSupport*' P:HBd2 2!HIf you have any questions regarding our Rayfract software and processing of your data sets, please contact us via e-mail at sales@rayfract.com. Also, check out our web site at httd p://rayfract.com for tutorials, application samples, links to theoretical papers etc.(% Hp;d5 8wHTutorials as available for download on our web site http://rayfract.com cover our Smooth inversion method and our older Delta-t-V method and following WET tomographic inversion only. While we do offer more conventional time-to-depth conversion methods (such as our Wavefront method) which require the user to assign refractors to segments of shot sorted or CMP (Common MidPoint) sorted and stacked traveltime curves, we really do not believe in the unqualified importance and usefulness of the theoretical concept of a "refractor" (i.e. a layer with no vertical velocity variation inside it) any longer. Once you assign first breaks to refractors you just force a model on the data at a very early processing stage and get relatively large errors (regarding refractor depths and velocities) in many situations later on.($% Hf2 2HThe identification of geological units / stratigraphic layers should be done once you have obtained the final tomogram only. The interpreter needs to realize that the tomogram shows the "in situ" subsurface seismic velocity. I.e. not just the material velocity component but also the stress field induced component : increasing overburden pressure with burial depth results in smaller sediment pores and less fractured rock. Stress magnitude variation at folds and faults may have similar local effects i.e. cause a systematic variation of seismic velocity (R. J. Twiss and E. M. Moores 1992 : pp. 429-431).($% H`p, &HAlso, mechanical and chemical weathering cause the rock quality and seismic velocity to decrease the closer the rock or sediment unit is to the surface. In other words, rock quality and seismic velocity tend to increase with increasing burial depth. See B. Murck 2001 : chapter 6 Weathering and Erosion : joints, exfoliation and frost wedging etc.(% H9p & 'HFor identification of stratigraphic units this stress and weathering induced velocity component needs to be "subtracted" from the subsurface velocity distribution as imaged. You then obtain the estimated material velocity component and may correlate that velocity with geological units as known to exist in the area i.e. from a geological map or core drilling. Of course it is very difficult to mathematically formalize this "subtraction" i.e. separation of the velocity components. It needs to be done mentally by the observer.( % H( ! % H( I % H4! } % HBibliography(I  % H} U ) HM. Ali Ak 1990. An analytical raypath approach to the refraction wavefront method. Geophysical Prospecting, volume 38, pp. 971-982.( } % HU K / ,?HBarton P. and Barker N. 2003. Velocity imaging by tau-p transformation of refracted seismic traveltimes. Geophysical Prospecting, volume 51, pp. 195-203.(} s % HK #) HE. Brueckl 1987. The Interpretation of Traveltime Fields in Refraction Seismology. Geophysical Prospecting, volume 35, pp. 973-992.(s K% H#) ?HJ. B. Diebold and P. L. Stoffa 1981. The traveltime equation, tau-p mapping, and inversion of common midpoint data. SEG Geophysics, volume 46, pp. 238-254.(K;% H @) 3HW. Frei 1995. Refined field static corrections in near-surface reflection profiling across rugged terrain. The Leading Edge, April 1995, pp. 259-262.; @ (;4@% H= @qA) )HGawlas, Peter Florian 2001 Ph. D. Thesis. Mglichkeiten eines DMO-Prozesses in der CMP-Refraktionsseismik. LMU Munich: Faculty of Geosciences. See http://edoc.ub.uni-muenchen.de/archive/00000222/01/Gawlas_Peter.pdf . Describes XTV inversion in chapter 3.2.2.4, page 43 ff.(4@A% HqAB, &HH. Gebrande 1986. CMP-Refraktionsseismik. Paper presented (in German) at MintropSeminar / Uni-Kontakt Ruhr-Universitaet Bochum, Expanded abstract "Seismik auf neuen Wegen", pp. 191-205.(AB% HBC, &sHH. Gebrande and H. Miller 1985. Refraktionsseismik (in German). In: F. Bender (Editor), Angewandte Geowissenschaften II. Ferdinand Enke, Stuttgart; pp. 226-260. ISBN 3-432-91021-5.(BC% HCD) HBruce S. Gibson, Mark E. Odegard and George H. Sutton 1979. Nonlinear least-squares inversion of traveltime data for a linear velocity-depth relationship. Geophysics, volume 44, pp. 185-194.(CD% HDE) HJ. G. Hagedoorn 1959. The Plus-Minus Method of Interpreting Seismic Refraction Sections. Geophysical Prospecting, volume 7, pp. 158-182.(DE% HETF) HGlyn M. Jones and D. B. Jovanovich 1985. A ray inversion method for refraction analysis. Geophysics, volume 50, pp. 1701-1720.(E|F% HTFoG) HI. Lecomte, H. Gjoystdal, A. Dahle and O.C. Pedersen 2000. Improving modeling and inversion in refraction seismics with a first-order Eikonal solver. Geophysical Prospecting, volume 48, pp. 437-454.(|FG% HroG1H( HTak Ming Leung 1995. Examination of the optimum XY value by ray tracing. Geophysics, volume 60, pp. 1151-1156.(GYH% H1HI) HTak Ming Leung 2003. Controls of traveltime data and problems of the generalized reciprocal method. Geophysics, volume 68, pp. 1626-1632.(YH7I% HiII( HB. Murck 2001. Geology. A Self-Teaching Guide. John Wiley & Sons, Inc., New York. ISBN 0-471-38590-5.(7II% HIJ) 9HD. Palmer 1980. The Generalized Reciprocal Method Of Seismic Refraction Interpretation. Society of Exploration Geophysicists, Tulsa. ISBN 0-931830-14-1.(IJ% HJK) HPascal Podvin and Isabelle Lecomte 1991. Finite difference computation of traveltimes in very contrasted velocity models: a massively parallel approach and its associated tools. Geophysical Journal International volume 105, pp. 271-284.(JL% HKL, &WHWilliam H. Press, Brian P. Flannery, Saul A. Teukolsky and William T. Vetterling 1986. Numerical Recipes. Cambridge University Press, Cambridge. ISBN 0-521-30811-9.(LM% HLM) HT. Ruehl 1995. Determination of shallow refractor properties by 3D-CMP refraction seismic techniques. First Break, volume 13, pp. 69-77.(MM% HMN) HGerard T. Schuster and Aksel Quintus-Bosz 1993. Wavepath eikonal traveltime inversion : Theory. Geophysics, volume 58, pp. 1314-1323.(MN% HT+N4) WHSheehan J.R., Doll W.E. and Mandell W.A. 2005a. An Evaluation of Methods and Available Software for Seismic Refraction Tomography. Journal of Environmental and Engineering Geophysics, volume 10, pp. 21-34. ISSN 1083-1363, Environmental and Engineering GeophN4 ysical Society. JEEG March 2005 issue.(N\% H4G) HSheehan J.R., Doll W.E., Watson D.B and Mandell W.A. 2005b. Application of Seismic Refraction Tomography to Karst Cavities. U.S. Geological Survey Scientific Investigations Report 2005-5160.(\o% HiG( HRobert J. Twiss and Eldridge M. Moores 1992. Structural Geology. W. H. Freeman and Company, New York.(o(% H݂) HToshiki Watanabe et al. 1999. Seismic traveltime tomography using Fresnel volume approach. SEG Houston 1999 Meeting, Expanded Abstracts.((% Hq݂( HD. J. White 1989. Two-dimensional seismic refraction tomography. Geophysical Journal, volume 97, pp. 223-245.(ƃ% HĄ) HRoland A. Winkelmann 1998 Ph. D. Thesis. Entwicklung und Anwendung eines Wellenfeldverfahrens zur Auswertung von CMP-sortierten Refraktionseinsaetzen. Akademischer Verlag Muenchen, Munich. ISBN 3-932965-04-3.(ƃ% H(Ą% H(<% H>z& 1HCopyright 1996-2008 Intelligent Resources Inc. All rights reserved. Rayfract is a registered trademark of Intelligent Resources Inc. in Canada and in Switzerland. All other product names as mentioned above are trademarks or registered trademarks of their respective holders.K<ņ1MņInstallation and licensing@z# :Installation and licensingQ&ņV+ $MTo install the Rayfract trial, please proceed as described below :For installation under Windows NT/2000/XP/VISTA please login as a user with "Administrator" rights.Download the installable archive file RAYTRIAL.EXE from our web site http://rayfract.com, link "Trial" or directly from the associated URL address http://rayfract.com/trial/RAYTRIAL.EXE. Start up your web browser such as Mozilla Firefox or Microsoft Internet Explorer. Then specify one of these addresses in the URL address field on top of the browser window and hit Enter.U-( [Once you have downloaded RAYTRIAL.EXE, copy it into a temporary directory on the target hardware, e.g., C:\TEMP or C:\TMP.To start up the self-installing archive, run ...\RAYTRIAL.EXE from DOS or from Windows. Please substitute drive name and directory path into which you copied installation file RAYTRIAL.EXE for ... . Click on the Start button, and then select menu item Run, at the bottom of the menu. In the Run dialog that now appears, key in above command line, with correct drive and directory path (e.g. command line "C:\TEMP\RAYTRIAL.EXE").~WV)' Alternatively, specify the command line by clicking on your Browse/Search button, displayed at the bottom of the Run dialog. In the following, first navigate to the hard disk partition and directory containing your archive file RAYTRIAL.EXE. Then select this file by clicking on it. To execute the command line, press the ENTER/RETURN key, or click on the OK button.When the installation program displays the "Select Destination Directory" dialog, please change the drive or partition part of the directory only and leave the rest as \RAY32 root level directory as per default (e.g. D:\RAY32).T(, &QTo verify the positive outcome of above installation, please test starting up the Rayfract trial, as described below :To start up Rayfract, proceed as follows : Under Windows 98 or NT/XP/VISTA click on the Start button. Open the "Programs" folder with a click on the left mouse key. Then click on folder "Rayfract" and the Rayfract icon contained in that folder, also with your left mouse key.The Rayfract trial li)zcense will expire after 50 runs, or 30 days after having been run for the first time. It will run without the need for any )( initial registration. When you start up the trial, the licensing dialog will display. Just hit RETURN or click on the "Continue" button to continue.Once the license has expired on a given hardware, the free trial will not run any longer run on that hardware, even if you reinstall it as described above. You do have the option to rent or purchase a full functionality license : 4 month rental or unlimited license. For details see our web site http://rayfract.com/pricing.htm #- (. You are welcome to pass on the trial installation file RAYTRIAL.EXE and this file TRIAL.TXT to any interested third party by any means as long as you do not charge them for the free trial and correctly display our Rayfract registered trademark.Here some more information concerning usage and functionality restrictions of your free trial Rayfract software :For a .PDF version of our Windows help file, please see http://rayfract.com/help/rayfract.pdf . This may be easier for viewing. &% Now you are ready to work with your license. You may first want to open the existing sample profiles LINE14 and PALMFIG4. Select the SEIS32.DBD in these subdirectories, to open the profile database. See "Starting up Rayfract and profile management" and later topics of the online help for details. You may start up the online help by selecting menu items in the rightmost Help menu. Be sure to read topic "System limitations" as well. There you will find a complete list of restrictions related to your trial( license.We recommend to get acquainted with the processing capabilities of our Rayfract software by working through the introductory "Tutorial" chapter of our manual as available at http://rayfract.com/help/manual.pdf . Or work through some of the tutorials at http://rayfract.com/tutorials/TUTORIAL.ZIP. The original data sets are available for download. Just click on the corresponding link in the tutorial.Please be aware that your trial license will handle up to ten shots per profile only ! We recommend to renumber the shots to 0 to 9 during import. Just edit the "Shot Number" field value in the "Import Shot" dialog. See the online help / topic "System limitations" for Rayfract versions with extended capabilities.' To obtain more information on an edit field in a dialog, please click on that field with your left mouse key and then press function key F1. This will cause a help popup window to be displayed.To automatically grid and plot/display Delta-t-V method output, you need to install Golden Software's Surfer version 8. You may download a free demo version at http://www.golden.com. Enter e.g. state CA for registration. You need to start up the free demo Surfer interactively via Start menu after (re)installing it. Then click on the splash screen, which covers the Surfer window. If you skip this step, Rayfract is not able to call Surfer automatically for plotting. For the full version, please startup Surfer and enter your license number first. + $The WIBU-KEY copy protection device help file WkUseUS.CHM is available athttp://rayfract.com/help/wkuseus.chmIf your Rayfract license comes with a WIBU license management hardware device, please proceed as follows :,Y aP:H"".Z""Connect this device to your PC's parallel port (in between the port and the printer cable) or an USB port, as appropriate.Try to start up your Rayfract software (installed as described above). See topic Starting up Rayfract and profile management.If the Rayfract main menu is displayed without any preceding message box, please skip the following instructions, since your license has been activated alzready.If the software displays a message box mentioning the WIBU key copy protection device, please complete the following instructions.&Y UP:H""""In order to activate/update/upgrade your license, you need to generate a context file for your WIBU-KEY, as lined out in the following steps.Select menu item "Settings" in your Windows 95/NT4.0 Start menu.Select submenu item "Control Panel".Double click / open the WIBU-KEY icon_5 :PHl"Left-click on small icon to left of dialog title bar, select "Advanced Mode" if availableIT vP:H""""Click on tab "WIBU-BOX Context" of the WIBU control applet now displayed.Click on text field "Remote Programming Context File".Enter an output context file name, e.g. "C:\TEMP\PROGRAM.RTC" into that field.Press the "apply" button.'- (HOnce you have produced the context file, please e-mail it to us (as binary e-mail attachment) so that we can activate/update your Rayfract license electronically. We will send you a license update file in order to do so, along with instructions on how to process the update file. If your rental license has expired and you wish to purchase a refill or unlimited license, we will require you to transfer the corresponding funds at such a time, or fax us your credit card charge authorization details.C_1_System limitations8# *System limitations_, &Your full functionality Rayfract license is a Windows 32-bit application (compiled with Microsoft Visual C++ 2005) and has the following inherent limitations regarding size of data sets etc. :H  qP:H""""""handles processing of seismic lines with up to 1000 shots per profilesupports reading in of shots recorded with from 12 to 360 traces per shot recordsupports processing of seismic lines with up to 360'000 traces per profileminimum / maximum sample rate is one microsecond / one secondmaximum of 10,000 samples per tracesupports raytracing through Surfer grid files with up to 640'000 nodes per grid > JP:H""assumes that trace data in .ASC ASCII files is sorted by increasing shot nr. and increasing receiver station (for same shot)all traces keyed to the same shot must be listed in the same .ASC ASCII file.S 6W |HƔ牀áܯ;To check whether you recorded enough shots for your profile, please review the Midpoint breaks display, by selecting Refractor|Midpoint breaks. Now map traces to refractors. If at a significant number of CMP's the traveltime curves start at an offset larger than 1 (i.e. are not connected to the top horizontal axis), subsequent inversion with Delta-t-V will become unstable because the weathering layer velocity is not constrained sufficiently with direct wave first breaks. You may improve the situation somewhat by increasing the CMP stack width (display and Delta-t-V) parameter. This amounts to widening the running average filter, for smoothing and interpolation of the weathering velocity. Velocities as determined below the shot points will be propagated to CMP's between the shot points, where no weathering velocity can be determined directly. But this may not help in all cases, especially if the weathering velocity varies laterally to a substantial degree (which may often be the case).  WAU xH]zOH>COur Delta-t-V and WET tomography inversion methods require a shot spacing of 6 receiver stations or smaller. 6WAOptimally shot points will be positioned at each 3rd receiver station or closer. Also, please use a receiver spacing of 10 metres or less. Finally, we recommend to employ multiple overlapping receiver spreads with at least 24 channels per spread, per Rayfract profile. Please record 10 or more shots per receiver spread.\/6D- (_H"Conventional" time-to-depth inversion methods (Wavefront, Plus-Minus, CMP Intercept-Time Refraction) will generally deliver more shallow refractor interpretations than the Delta-t-V method. This is because while the Delta-t-V method optimally models gradual velocity increase with depth inside one layer, these conventional methods assume that velocity inside one layer remains constant with increasing depth (below top surface of layer). As a consequence, raypath segments within one layer will be modeled as straight lines. Corresponding raypath segments within layers as modeled with the Delta-t-V method are arcs of a circle, determined by the vertical velocity gradient as modeled for each layer. These diving wave paths penetrate deeper into the subsurface than the conventional straight segment paths.BWA@GK dHH>]zOPlease note that we strongly recommend to refine subsurface velocity models as obtained with our Delta-t-V method with our new Wavepath Eikonal Traveltime WET tomography algorithm. This makes sense especially in situations of extreme topography (with absolute line elevation deviation from a horizontal or inclined flat plane along one receiver spread about equaling or exceeding the target depth being imaged). Please check topic Delta-t-V Inversion for more details on data acquisition requirements, such as coverage of profile receivers with first breaks etc.(DhG% H@G}H4 6HThe free limited functionality Rayfract trial license is a Windows 32-bit application as well (compiled with Microsoft Visual C++ 6.0 SP 5) and has these time and run limitations, as well as functional limitations :|hGI` ?P:H"""will expire after 30 days or after 50 runs, whichever happens firstsupports up to 10 shots per profile only. You will need to renumber your shots as shot number 0 to shot number 9.supports raytracing through Surfer grid files with up to 100'000 nodes per grid only}HJS tPHl""does not support topography specificationdoes not support Crosshole survey Smooth inversion, with WET tomographyYI[K7 >P:H"does not support interactive Wavepath Eikonal Traveltime WET tomography processingIJK8 @PHl"does not support interactive pseudo-2D Delta-t-V and XTV inversion[KL= HIP:H""does not offer time-to-depth inversion methods Wavefront and CMP intercept-time refractiondoes not offer Midpoint breaks display and Offset breaks display~IK9M5 :PHl"Trace|Midpoint gather and Trace|Offset gather displays are disabledLKOY {P:H""""does not support importing or specifying shot and receiver station coordinates. Assumes a straight line recorded on a flat topography.does not support importing or specifying lateral shot position offsets and shot hole depthsdoes not offer semi-automatic first break picking for shot sorted trace gathers, in the Shot breaks displaydoes not support printing of trace gathers/time sections/depth sections and velocity sectionsA9M> J P:H""when importing or updating first breaks e.g. from Interpex Gremix .GRM files and OYO SEISREFA .ODT files, receiver eKOlevations and shot hole depths will not be updateddoes not support exporting station and shot point coordinates to .COR and .SHO filesL%KO' KHThe trial license will expire whenever either it has been run 50 times, or after 30 days have passed. You may then purchase a 4 month rental or unlimited license. See our web site at http://rayfract.com/pricing.htm . Please contact us for further details, by e-mail to sales@rayfract.com .*' P:HKY1YStrong refractor curvatureB% :HStrong refractor curvature(YÂ% H2 2HTFor true 2D WET tomography processing of profiles with strong basement undulations, we recommend to use our Smooth inversion method, based on a 1D gradient initial model. See e.g. our tutorials(Â% HU0:% `Hhttp://rayfract.com/tutorials/broadepi.pdf ,V1% bHhttp://rayfract.com/tutorials/depress.pdf andU0:% `Hhttp://rayfract.com/tutorials/palmfig3.pdf .( % H(5% H , & HAs shown in the last tutorial, to prevent velocity artefacts in the imaged basement, your profile (overlapping receiver spreads) should extend over the edges of a basement depression (e.g. a steep valley). You may need to limit the maximum imaged basement velocity during inversion to a value estimated e.g. with our Wavefront method; see http://rayfract.com/tutorials/palmfig3.pdf .(5 % H(5% H( ]% H(5% HR]0Y H]|A Ɣ{s.FFor conventional refraction interpretation of strong basement topography undulations, we recommend to prefer Wavefront and Plus-Minus interpretation results over CMP intercept time refraction interpretation. These interpretations may be based on semi-automatically mapping the first breaks to refractors in the Midpoint breaks display. Alternatively, you may want to manually map the first breaks to refractors for each shot sorted traveltime curve, in the Shot breaks display. For low coverage data, this is the only option available for mapping first breaks to refractors.(X% H(0% HX8 >H ĝ؉Conventional CMP intercept time refraction fails to deliver accurate refractor depths and velocities at locations of strong refractor curvature, such as at the top of steep/narrow anticlines and at the bottom of steep/narrow synclines. In case of constantly dipping refractors, sorting the traces by Common Mid Point (CMP) basically eliminates intercept time and slope errors caused by refractor dip. This automatic error correction does not work in situations of strong refractor curvature, however. The two delays (relative to the horizontal layering case) of raypath segments traveling down to the refractor and coming up from the refractor null out each other symmetrically to the CMP for each ray mapped to the same CMP in case of constantly dipping refractors. This is not true with strong refractor curvature. In such situations, delays along the down going and the emerging raypath segments of each ray add to each other, instead, with increasing offset from the CMP.(% Hrn8 >HƔAs a consequence, expect apparent CMP velocities at the vertex of steep/narrow anticlines (refractor humps) to be too low by about ten to twenty percent. In analogy, expect apparent CMP velocities at the bottom of steep/narrow synclines (refractor troughs) to be too highn by about the same percentage. Please note that semi-automatically mapping first breaks to refractors in the Midpoint breaks display will work even in such situations of strongly undulating refractors, however. I.e. laterally varying crossover distances can be determined reliably even in case of slightly wrong apparent CMP refractor velocities.(% H`4n, &iHIf CMP basement velocities and CMP basement depth show a strong correlation for certain station numbers, there is a high chance that refractor synclines/anticlines are located below these station numbers. This location information may be useful when interpreting Wavefront and Plus-Minus depth sections.D:1~:swOptimize Windows XP9s# ,Optimize Windows XP:h2 2Windows XP's default configuration is far from optimized. See e.g. PC Today August 2004 issue, page 70 and following pages for more details. Here we first focus on optimization of disk access :The Indexing Service in Windows XP indexes your files presumably to shorten the time needed to search your hard drive if you are looking for a specific file or part of a phrase inside a file. However, the constant indexing of files actually slows down system performance considerably. Specifically, the hard disk is accessed almost all the time. You may witness this by observing the constant flashing of the hard disk drive diode or similar.To disable the Indexing Service permanently, click Start and Run. In the Run dialog box, type services.msc and press ENTER or click OK. In the Service window, scroll down and right-click the Indexing Service entry. Select Properties from the pop-up menu. Click Disabled from the Startup Type drop-down and click OK.s. *Furthermore, we recommend to disable file search indexing for Microsoft Office. Click Start and Control Panel. Now double-click the icon with the binocular and yellow flash graphics. Then select menu item "Stop indexing" or similar, in menu "Index".The startup time for Windows XP is acceptable if you use the Suspend / Resume mode, e.g. on a Toshiba portable. XP suspends when you close the lid and resumes when you reopen the lid of your portable. On a desktop PC, click Start and Turn Off Computer. Once the Turn off computer dialog appears, press down and hold the SHIFT key. Now click on the yellow "Hibernate" button. When you restart your PC, Windows XP will be restored almost instantly to the state it was before you turned it off.zh.3 4If you note that Windows XP is running slower and slower, please shutdown XP via the Start menu "Turn Off Computer" item. Then start up XP again. If program execution under Windows XP is still slow and you are using the ZoneAlarm Internet Security Suite, please disable the ZoneAlarm OSFirewall component. Go into the main tab of "Program Control". Now click on the "Custom" button in the "Program Control" area. Uncheck "Enable OSFirewall" and click on "OK". If program execution and disk access is still too slow, you may want to stop a currently running ZoneAlarm virus scan, or shut down and uninstall/reinstall ZoneAlarm., &+We recommend to shut down all other non-essential applications before starting inversion with our WET method. Also, you may want to upgrade the amount of RAM installed in your work station or notebook computer, to the maximum amount allowed by your Windows version. Under Windows XP 32-bit, the maximum supported RAM amounts to 4 GBytes. For Microsoft Windows versions supporting more RAM, please seerL.a& http://www.microsoft.com/whdc/system/platform/server/PAE/PAEmem.mspx .$7 <To delete temporary Internet files and cookies, we recommend a file-cleaning program such as R-Wipe &a Clean. Seehttp://www.r-tt.com . Run it about once a week. Select Tools|Settings... and select Wiping Algorithm Pseudo-random for acceptable performance. To streamline and clean up your Windows Registry on a weekly basis or so, we recommend CleanMyPC. Seehttp://www.registry-cleaner.net . Be sure to first make a backup of the registry, when starting up CleanMyPC.a= HTo archive Rayfract profile database files seis32.* and WET tomography output files *.GRD etc. as written to profile subdirectories GRADTOMO (Smooth inversion) and TOMO (Automatic Delta-t-V and WET inversion), we recommend WinRAR. Seehttp://www.rarlab.com .For safe Internet access, we recommend to stop using Microsoft Internet Explorer and use e.g. the free Mozilla Firefox browser instead. For details seehttp://www.mozilla.org/products/firefox .45 8Also, we recommend to stop using the Microsoft Outlook Express e-mail client and use a more secure alternative such as Eudora, with automatic HTML display disabled. Even better, always check your incoming e-mail in your webmail account and delete any spam. Only then download the relevant messages to your PC, with your local e-mail client.For more tips on securing your PC, we recommend the book "Computer Security for the Home and Small Office" Copyright 2004 Thomas C. Greene, ISBN 1-59059-316-2.xw' For tips on administering Windows Operating Systems in general, please see e.g.http://www.petri.co.il/index.htm .S"1@-IStarting up and profile managementR/w# ^Starting up Rayfract and profile management  ΀D-To startup Rayfract, proceed as follows : Under Windows 95 or 98 and NT 4.0, click the Start button. Then select menu item Rayfract and the Rayfract icon contained in that folder.Opening a profileIn order to open a profile, please select File|Open Profile. Now a file open dialog appears, prompting you to select a seis32.dbd database schema. All profile header, shot header, trace header, binary trace data and resulting model data related to one profile is stored in one Rayfract profile database, defined by a seis32.dbd database schema. Exactly one database is stored per file system subdirectory. The sample profiles are located in directories \RAY32\LINE14 and \RAY32\PALMER. If you want to open a profile which you created earlier on, please select the directory you specified when you created it via New Profile. You may change the current profile database with File|Open Profile at any time. The current profile's directory path is displayed in the application's title bar.@F Zg Defining a new profileTo initialize a new profile, select File|New Profile. Next, the Create New Profile dialog is displayed. Either accept the default new profile subdirectory proposed or enter a unique new profile name (whole directory path or just subdirectory name, up to 8 characters) in edit field file name. Please note that long format directory names (containing spaces or longer than 8 characters) are not allowed. Select the drive to contain the new profile with the drop down list at the bottom of the dialog. Specify the directory to contain the new profile (i.e. its parent directory) via the directory list control in the center of the dialog. Navigate to that parent directory by consecutively double clicking directory levels, starting at the root \RAY32 directory of the drive selected. We recommend to have a directory \RAY32 in the root directory of your hard-disk volume (does not have to be drive chosen at installation time), and then create subdirectories in that root level directory, one for each profile to be pr @wocessed. Once you have specified above information, click OK in order to generate the new profile database and to open it as the current database.  EA P Now a new empty Rayfract profile database will be generated, in the subdirectory as specified above. The database component files are named seis32.d?? and seis32.k??. The database will be filled in once you import seismic data files; see below.Once you have generated the profile as just described, select Header|Profile and fill out at least edit fields Line ID, Job ID, Instrument, and Station spacing (in meters).Then hit RETURN.Please note that creating a new profile may fail in certain rare circumstances. These typically are low disk space situations. The software will display an error message indicating the problem and how to proceed. It will shut down once you accept the dialog (with RETURN or by clicking on the OK button). We recommend to reboot your PC in such a situation, and to make sure that there is ample disk space on both your C: drive, the drive/partition onto which you installed Rayfract, and on the partition on which you tried to create the new profile database. 400 MBytes of free disk space on each of these drives/partitions should be safe. Then delete the invalid profile subdirectory within Windows Explorer (see below) and re-create it with Rayfract (File|New Profile...).@IQ paValidating a profile databaseYou may check the consistency of the profile database currently opened by selecting File|Check Profile at any time. The resulting message "0 errors were encountered in 0 records/nodes" signals that your profile database is in a consistent state.Renaming and deleting Rayfract profilesTo rename and delete Rayfract profile subdirectories, start up your Windows Explorer. E.g. select Start|Run..., enter command line "Explorer" and hit ENTER. Now navigate to the drive containing your \RAY32 data root level directory. Click on the \RAY32 directory with your left mouse key. Then click on the targeted subdirectory label. Now click your right mouse key and select menu item Rename or Delete. If your selected Rename, now enter the new subdirectory name (i.e. profile name) and then hit RETURN. If you selected Delete, confirm the following prompt to delete the subdirectory and its content.(EI$ U$I(J1 (JrJvDialog box control and function keysJ'IrJ# NDialog box control and function keys2(JMp eUse the TAB key in order to cycle through the control fields, i.e. to change the input focus. Use the RETURN key in order to confirm the dialog box changes just made. Alternatively, click the OK, Read, Accept or equivalent button (if existing). Use the ESC key in order to cancel changes to the dialog box / not to carry out the transaction configured by the dialog box. Alternatively, click the CANCEL or equivalent button (if existing). Press F1 to obtain online dialog help on the dialog control currently holding the input focus.rJN& If you try to enter a new numerical parameter value with more digits than the current value (e.g. increase of WET iteration count, from 20 to 200) and our software does not allow you to enter the last / additional digit :(MOW |WPl"""move the "blinking I" cursor to the right end of the control field with END keypress the BACK SPACE key (bold left arrow symbol; located one or two rows above ENTER key) repeatedly to delete ALL current digitsonce the control field is empty, enter the new numerical value e.g. 200)NO% l O؀> Jl  O؀IIn the following, displays generated by selecting menu items in menu Trace are called Gather displays. Displays generated by selecting menu items in menu Refractor are called Breaks displays.(O% lzL؀z. ,l Here are the most important function keys for working with Rayfract :(% lCz7R#t+#S""8Function key combinationMeaning assigned to key combinationXX#+#S".  2F1Context sensitive online help in dialogs. Zoom time scale (Gather displays)..7gR#t\+#S"" F2Unzoom time scale (Gather displays).>}#Ȁ+#S"vu|s.FƔCTRL-F1Zoom traces, in amplitude coordinate (Gather displays). Pick Branch point 1, in Shot breaks display. Zoom CMP curves (reduced time axes) in Midpoint breaks display.GgPd#+#S"Fu|s.FDEL-CTRL-F1Delete Branch point 1, in Shot breaks display.B}#Ȁ+#S"vu|s.FƔCTRL-F2Unzoom traces, in amplitude coordinate (Gather displays). Pick Branch point 2, in Shot breaks display. Unzoom CMP curves (reduced time axes) in Midpoint breaks display.GP=d#+#S"Fu|s.FDEL-CTRL-F2Delete Branch point 2, in Shot breaks display.>͇R#t|+#S""CTRL-F3Toggle trace display modes, in Gather displays.g=X#+#S". F7Page backward (header data dialog boxes, gathers, traveltime curves in Shot breaks display)f͇JX#+#S". F8Page forward (header data dialog boxes, gathers,traveltime curves in Shot breaks display).TR#t+#S""PAGE DOWNPage downwards (increasing time) along time axis (Gather displays).PJR#t+#S""PAGE UPPage upwards (decreasing time) along time axis (Gather displays).Y=R#t+#S""CTRL-HOMEPage to up most time section (minimum recording time) (Gather displays).[R#t+#S""CTRL-ENDPage to bottom most time section(maximum recording time) (Gather displays).l =VL#h@+#S""ALT-PAGE DOWNSee F8 above.jL#h<+#S"ALT-PAGE UPSee F7 above.NV`R#t+#S""ALT-HOMEPage to first record (dialog box / gather / traveltime curve).LR#t+#S""ALT-ENDPage to last record (dialog box / gather / traveltime curve).P`R#t+#S""SHIFT-F1Zoom station number axis (horizontal axis), for Gather displays.RDR#t+#S""SHIFT-F2Unzoom station number axis (horizontal axis), for Gather displays.a R#t+#S""&SHIFT-PAGE DOWNPage to the right by one profile section / pan right, for Gather displays.D I]DR#t+#S"""SHIFT-PAGE UPPage to the left by one profile section / pan left, for Gather displays.H UR#t+#S""SHIFT-HOMEPage to leftmost profile section, for Gather displays.HR#t+#S""SHIFT-ENDPage to rightmost profile section, for Gather displays.lU[k#+#S"RƔALT-MDisplay Model parameter dialog, for Midpoint breaks (Trace to refractor mapping parameters), CMP intercept time refraction, Plus-Minus and Wavefront menu items/displays. Display Trace processing parameter dialog for Shot gather display.lR#t+#S""ALT-PDisplay Display parameter dialog, for Gather and Breaks displays / Depth and Velocity sections.p[R#t+#S""ALT-ADisplay Annotations parameter dialog, for Gather and Breaks displays / Depth and Velocity sections.DqR#t+#S""6Left button Mouse clickPick first break, in Gather displays.LR#t+#S""BSHIFT-Left button Mouse clickDelete first break, in Gather displays.q_#+#S":ƔARROW DOWNMove trace cursor down trace in Gather displays. Move CMP curve cursor to next larger offset in Midpoint breaks display._#+#S":ƔARROW UPMove trace cursor up trace in Gather displays. Move CMP curve cursor to next smaller offset in Midpoint breaks display.3k#+#S"RƔs.FARROW LEFTMove trace cursor one trace left in Gather displays. Move CMP curve cursor one CMP left in Midpoint breaks display. Move branch point pick cursor left in Shot breaks display.7Pk#+#S"RƔs.FARROW RIGHTMove trace cursor one trace right in Gather displays. Move CMP curve cursor one CMP right in Midpoint breaks display. Move branch point pick cursor right in Shot breaks display.&v# R!P1RData processing sequence overviewG$v# HData processing sequence overviewUds Ts.FƔC]Proceed by selecting menus / menu items from left to right : import data, edit header data (station spacing !) and pick first breaks semi-automatically or interactively. Now either process your profile automatically with Smooth inversion|WET with gradient initial model, or assign traces to refractors (manually in Shot breaks display, semi-automatically in Midpoint breaks display). Before starting to assign traces to refractors, decide if you want to model your data as a 2-layer case (1 refractor) or as a 3-layer case (2 refractors). When mapping traces to refractors in your Midpoint breaks display, set parameter Refractor count in Midpoint breaks display / Model parameter dialog (ALT-M) accordingly.I `Please note that whenever you repick first breaks, edit coordinates or delay times, or (re)import shots, first breaks or geometry, previous results and trace-to-refractor mappings will be reset. Also, (re)importing one or more shots will automatically reset the profile geometry. You will then need to update the geometry, e.g. via Fidvle|Update Station coordinates and File|Update Shotpoint coordinates. So it does make sense to regularly export station coordinates and shotpoint coordinates, via File|Export Station coordinates and File|Export Shotpoint coordinates. The resulting files are per default located in your \RAY32 profile subdirectory, and are per default named COORDS.COR and SHOTPTS.SHO.dR( IFor an illustration of typical data processing sequences, please see our manual and tutorial chapter, as available athttp://rayfract.com/help/manual.pdf .F1BReceiver spread types;R# 0Receiver spread types* "If you are processing your seismic data both with reflection seismics methods and refraction seismics methods, you typically have no other choice than planting your receivers at constant intervals. Otherwise reflection seismics processing may not work. High coverage data typically is recorded for interpretation with reflection seismics methods, and possibly for parallel interpretation with refraction seismics methods. For reasons of simplicity, you may also want to employ spreads with receivers separated from each other by a constant distance interval for low and high coverage refraction surveys. We actually recommend to employ these already defined, regularly spaced layout types whenever possible. ' For carrying out low coverage refraction seismics surveys, some parties prefer to define their own irregularly spaced layout types. You want to optimally map both the (typically thin) weathering layer (as indicated by direct wave arrivals, at near offset receivers) and refractors (as indicated by refracted wave first breaks, recorded at further offset receivers). To optimally map the direct wave velocity, you may want to place receivers close to each other and to the source at near offsets. To optimally map refracted wave velocities and intercept times, you need to record the refracted wavefronts over as long a distance as feasible with a limited number of channels. Resolution is not that important (and not easy to numerically achieve) for deeper refractors, so you will separate neighboring receivers by distances increasing with offset from source location. Note that we implicitly assume that velocity increases with depth, i.e. with refractor. E XOiZ\o4When importing seismic trace data recorded for one shot, you need to specify the spread type used (relative distances between adjacent receivers), the station spacing (scale at which spread type is actually planted), and finally the layout start. The layout start is expressed in profile relative, integer (whole) station numbers. The spread type is defined in spread relative integer station numbers. These relative station numbers are relative to the first/leftmost receiver position of the spread, as planted. The spread relative station number of the leftmost receiver position is always 0. The profile relative station number of the first spread receiver position is defined by layout start. So the software will be able to convert between spread relative and profile relative station numbers by means of the layout start, as entered during data import. For more details, please see Station numbers and spread types.= A PiZ\The station spacing is defined once only, for the whole profile. The corresponding edit field is located in your Profile Editor (Header|Profile).Note that we assume that channel 1 of your seismic data recorder always records trace data as registered by the receiver planted at the left limit (with station numbers increasing to the right)/start/lowest station number of your spread. If you have the habit of turning this recording convention around by 180 degrees sometimes, please let us know.P vAD VvARCFinally, we would like you to lay out your spreads such that they overlap by a few receiver positions, ideally by up to half the spread length. This makes data interpretation easier/safer, especially regarding absolute depth of refractors.To define your own receiver spread types, please see Defining your own layout types.aB0 .wʘgTo export your custom spread types to an ASCII text file, and to reimport such a text file into your reference database, please proceed as described in Import/export of layout types.*vAB& Q aBB1( B$CStation numbers and spread typesH#B$C% FStation numbers and spread types(BLC% $C#D& cThe "station number" concept is widely used in Reflection Seismics processing, and is helpful for the reliable and correct interpretation of Refraction Seismics data as well.(LCKD% #D/E2 2eiZ\The Interpex Gremix .GRM file format lists shot and receiver locations in metres, with the leftmost receiver conventionally positioned at an offset of one station spacing.(KDWE% /EiGD ViZ\Let us assume that during import of one shot with File|Import Data... , Layout start is set to station nr. 1, Station spacing is set to 4 metres, and the first layout receiver is located at "position" 4m, as indicated in a related .GRM file. Also, let us assume that this is a profile with just one equidistant receiver spread. In this case, station nr. 0 corresponds to a .GRM position of 0m, and station nr. 1 corresponds to a .GRM position of 4m.(WEG% iGpH& sTo convert a shot position in metres e.g. 12m to the left of the first profile receiver (corresponding to a .GRM location of -8m) to a station number, now please proceed as follows :(GH% >pHKE X}PliZ\1.Determine the signed distance between the shot position and the first profile receiver, e.g. -12m.2.To obtain the relative position in station numbers (relative to the first profile receiver), please divide this signed shot distance (from the first receiver) by the station spacing. E.g. -12m divided by 4m gives -3.3.Now add this relative position (in station numbers) to the absolute station nr. of the first profile receiver i.e. to the layout start. E.g. add -3 to 1 and obtain -2, as the "absolute" (profile relative) shot position in station numbers.HKA P PlR?h4.Finally enter this profile relative shot position (in station nrs.) into field Shot position, of the Import shot dialog.(K L% lK M@ NlTo get a better understanding of the conversion from positions in metres to positions in station nrs., please also review topics Receiver spread type and Defining your own layout types.( L4M% l MN0 .wlʘgTo export your custom spread types to an ASCII text file, and to reimport such a text file into your reference database, please proceed as described in Import/export of layout types.(4MGN% l(NoN% lGN#& lWe admit that the station number concept and the related concept of Receiver spread types may be a bit difficult to understand at first sight. Especially to users who up to now have processed their data with other software such as Interpex Gremix, W_GeoSoft WinSism, Earth FX VIEWSEIS etc. These packages let the user specify shot locations and receiver positionoN#Bs in metres directly.(oNK% l]#; FlThe advantages of our station number and related Receiver spread type concepts are :(K % lNYR rPl""much fewer recording geometry specification errors, especially in situations where the receiver spacing varies along the spread. Correct geometry specification is paramount for obtaining meaningful first break interpretations. We prefer to catch geometry errors as early as possible with mandatory redundancy in the specification, instead of giving your clients bad output based on an invalid geometry specification.let the user explicitly define and name his or her own receiver spread types.<  ڀPl""""]zOclear separation of the concepts "x coordinate" and "position in metres" vs. "station number".in situations of steep and strongly undulating topography, x and y coordinates can be corrected for the topography in the Station Editor (Header|Station), with buttons Correct x and Correct y.Station numbers always remain constant, independent of the topography.enable the easy and consistent database internal sorting of traces by CMP station number. This is a prerequisite for subsequent interpretation of first breaks with our Delta-t-V method.MYh1)# hK Overlapping receiver spreadsB# >Overlapping receiver spreadshJ b}&Q ƔAs specified in System limitations, we require that multiple receiver spreads overlap with each other, if you want to process shots recorded by these spreads as one Rayfract profile.In the following we assume that you want to import shots recorded with six overlapping receiver spreads. Each such receiver spread has 24 active receivers.If adjacent receiver spreads overlap at least at one receiver station, then you can process the shots recorded by these receiver spreads as one Rayfract profile. If there is no overlap between adjacent receiver spreads, then you have to process each spread separately. The less far offset shots you record for each spread, the more the spreads need to overlap to obtain a good coverage. If you don't record far offset shots at all, spreads need to overlap 25% or even 50% of their length. Otherwise resulting tomograms may show coverage gaps. To check the coverage, select Refractor|Midpoint breaks.RR rR?ho4When importing a specific shot, you need to review and if necessary adapt Layout start and Shot position in the Import shot dialog. See Station numbers and spread types for more information. We recommend to proceed as described below :x |o Pl""""create a new Rayfract profile database named e.g. "NIRMTEST", as described in our manual http://rayfract.com/help/manual.pdf.now open a DOS box e.g. via Start|All Programs|Accessories|Command Prompt.now generate a separate subdirectory for each of your 6 spreads, named e.g. \RAY32\NIRMTEST\SPREAD1 etc. with md command.copy the binary trace data and ASCII header data (Interpex Gremix .GRM etc.) files for each spread into the corresponding subdirectory, with copy command or in Windows Explorer.#S tPl""R?hmake sure that shot numbers are unique over all spreads imported. E.g. rename shot nr. 1 of SPREAD1 to shot nr. 11, shot nr. 2 of SPREAD1 to shot nr. 12, ..., shot nr. 3 of SPREAD4 to shot 43, ..., etc.You can rename either the .DAT trace data files in subdirectories SPREAD1 ... SPREAD6 : renam|e 1.DAT to 11.DAT for SPREAD1, ..., rename 3.DAT to 43.DAT for SPREAD4, ..., etc. Or you can renumber the shots during import, in the Import shot dialog.G|u ԀPl"tp΀"tp΀o4now import shots for SPREAD1 into profile NIRMTEST, as described in http://rayfract.com/help/manual.pdf. Set Input directory to \RAY32\NIRMTEST\SPREAD1. Leave Layout start at its default value of 1.0.now import shots for SPREAD2. Set Input directory to \RAY32\NIRMTEST\SPREAD2. Adapt Layout start to the profile relative station number of the first receiver of SPREAD2. E.g. if the first receiver of SPREAD2 is positioned at station nr. / receiver nr. 19 of SPREAD1, then set Layout start to 19.0. See Station numbers and spread types for more details.F[ Pl"""mGux]set Shot position for shots recorded with SPREAD2 to the spread relative shot pos. (starting at 1.0) PLUS the difference between Layout start for SPREAD2 and Layout start for SPREAD1. E.g. if a shot is positioned at station nr. / receiver nr. 3 of SPREAD2, specify its shot position as 3+ (19-1) = 3+18 = 21.0.proceed with importing shots from SPREAD3 etc. as described above for SPREAD2.instead of determining layout start and shot position manually as above, you may want to uncheck import option File|Import Data Settings|Keep same Layout start for consecutive shot trace files. Then our import routine will determine layout start and shot position directly from the SEG-2 trace headers. Of course this will work reliably if SEG-2 trace headers contain valid recording geometry information only.(u% l([% lP nl  If your input data is formatted as ASCII .ASC/Interpex Gremix .GRM/OYO SEISREFA .ODT, W_GeoSoft WinSism .XYZ, Earth FX VIEWSEIS .PRN files, OPTIM LLC SeisOpt or Geometrics SeisImager PickWin/PlotRefa .VS, you may copy all files relevant for one profile (one file per overlapping receiver spread or "line") into the same subdirectory. Then select one of these files in the Import Shots dialog, with the Select button. Now select the correct receiver spread type etc. and click on button Import shots. Now shots specified in all matching files (regarding file extension) stored in the same subdirectory will be displayed in the Import Shot dialog and may be imported with the Read button.(% ldJ blPlease note tha