This section provides a Select Sesimic... button which will allow you to pop-up a seismic selector dialog. This section also allows you to specify the 3D Survey Area to be used to retrieve trace data for Broadband analysis.

Input Seismic tab from the Select Input Data dialog
	The picture to the left shows the Input Seismic tab when using this tool as a plugin to OpendTect. Seismic data can be selected by pressing the Select Seismic... button. The seismic data selector will display all the available seismic cubes. If the volume list is long, then you can use the volume filter field to immediately reduce the number of entries thus making it easier to select the particular seismic volume needed for the analysis.
	The picture to the left shows the Input Seismic tab when using this tool as a plugin to Petrel. The Seismic : push button allows you to use the currently selected 3D seismic cube/2D seismic line from the Petrel input tree as the seismic volume for use within the Frequency Shaping application. Subsequent pictures in this section are of the OpendTect variant.
	The picture to the left shows the Input Seismic tab when connecting this tool to OpenWorks. Begin on this tab by selecting a Survey by pressing the Select Survey... button. After a survey has been selected seismic data can be selected by pressing the Select Seismic... button. The seismic data selector will display all the available seismic cubes. If the volume list is long, then you can use the volume filter field to immediately reduce the number of entries thus making it easier to select the particular seismic volume needed for the analysis. In order to connect Frequency Shaping to an OpenWorks database it must be run within an OpenWorks environment. An OpenWorks System Terminal Window will provide a suitable environment. A Project must first have been selected from the Main Window's File -> DB Project selector. Subsequent pictures in this section are of the OpendTect variant.

With the seismic data selected it usually desirable to define a sub-area. This is achieved by clicking the Sub button from the 3D Survey Area radio button group. Following this the user would select sub-area using the Start In-line, End In-line, Start X-line and End X-line edit boxes. Finally, the number of traces is specified and the Load Seismic button is clicked.

With the seismic data volume selected you can now load a set of traces to be analysed. Here you can optionally choose to select traces from the full 3D survey area or sub 3D survey area. This is achieved using the 3D Survey Area radio button group as follows:

Typically you would select a single sub-area. Specifying a sub-area in this manner enables you to include an area of the survey where the trace data is known to be of good quality and is representative of the survey area as a whole. With sub-area selected it is simply a case of specifying the number of traces to load (default 40) via the Num. Traces spinbox widget. This is then followed by you clicking the Load Seismic button to load a random set of traces. A list of the randomly loaded traces is then displayed in the Input tab beneath the Load Seismic button. At the same time an alternative set of traces is also loaded. These alternative traces are listed in the QC tab and are used with the derived operators for QC purposes. The software also enables you to select trace data from multiple sub-areas. This is achieved by specifying another In-line/X-line Start and End range and clicking the Load Seismic button again. The goal is to generate seismic trace spectra which is a good representation of the area as a whole. If you attempt to specify an area which is outside of the available area then a warning message will be issued when you attempt to load seismic traces by clicking the Load Seismic button. You will also get an error message if you set an area which would not allow enough unique traces for the Num. Traces requested.

Figure 4.17. Loading Seismic Data

The image in the figure above shows the application main window with Select Input Data Dialog superimposed. The Raw Seismic spectra resulting from clicking the Load Seismic button on the "Select Input Data Dialog" (above left) with Num. Traces set to 40 and a 3D Survey Area is defined by:

In-line: 1000 - 1600

X-line: 1000 - 1480

By default, all loaded traces are used in the spectra calculation and contribute to the Seismic Mean Spectrum. However, you can remove a given trace from the Frequency Shaping analysis by deselecting it via the Input list. Deselection of a trace is simply achieved by unchecking the checkbox within the list. If you want to completely remove the deselected trace you click the Clear Unselected Traces button. Alongside each trace on the Input list, are various properties associated with the trace. These include Trace Id (or trace label), In-line, X-line, RMS Amp, RMS Err, Horz Time. The RMS Amp property is derived from the input seismic trace, whereas the RMS Err property is derived from the trace spectrum. The latter can be considered as a "goodness of fit" parameter as it compares trace spectrum with the smooth mean trace spectrum. So for RMS Err, the smaller the number the better the fit. Loaded traces, by default, are sorted by Trace Id. However, you can sort the list of traces using one of the other properties. This is easily achieved by clicking the column header on the Input list. So, for example, if you want to sort by RMS Amp in ascending order, you click the RMS Amp header label. To sort in descending order you click the RMS Amp header label again. You can also change the position of the property columns. This is simply achieved by clicking and holding on a property header then dragging the property header to its new position.

The image shows the result of clicking the Load Seismic push button. Here 40 traces have been randomly loaded and immediately displayed in the "Raw Seismic" chart within the application main window. Also visible is a portion of the "Select Input Data Dialog" showing the trace list on the "Input" tab sorted by ascending RMS Amplitude values.

Figure 4.18. Clearing Seismic Data

The image in the figure above shows the result of clicking the Clear Traces push button. Clear traces removes all traces previously loaded to memory and has the immediate effect of removing this data from the "Raw Seismic" chart within the application main window.

Specifying the time range (gate) is an important step. Ideally, you should choose a time gate in the range of 500 - 1000 msec which should be over the zone of interest. You can set the Time Range mode in one of three ways via the "Range" radio button.

Of the three options the Horizon Range mode is the preferred mode since it allows the gate to follow the geology and should, with a well interpreted horizon in the target zone give, in theory, trace spectra which are more closely matched.

Figure 4.19. Modifying Seismic Time Range (Full)

The image in the figure above shows the application main window with Select Input Data Dialog superimposed. Here, "Full" (full trace range) has been selected for the Range radio button. This mode is rarely used since our goal is to design the operators over the zone of interest. This will optimise the process over that zone. However, it does allow you, although insensitive, to see the start and end times of the entire trace.

Figure 4.20. Modifying Seismic Time Range (Sub)

The image in the figure above shows the application main window with Select Input Data Dialog superimposed. Here, "Sub" (sub trace range) has been selected for the Range radio button. In this mode the Absolute Start time and the Absolute End time Line Edit fields will be sensitised. This allows you to specify a time gate for the zone of interest. Typically, you would specify a time gate which has a time range between 500msec and 1000msec.

Figure 4.21. Modifying Seismic Time Range (Horizon).

The image in the figure above shows the application main window with Select Input Data Dialog superimposed. Here, "Horizon" (horizon relative trace range) has been selected for the Range radio button. In this mode the Relative Start time and the Relative End time Line Edit fields will be sensitised. This allows you to specify a time gate for the zone of interest. Typically you would specify a time gate which would give you a time range between 500msec and 1000msec. Specifying the Start and End times here are relative to a geologic horizon. A negative number represents time above the horizon whereas a positive number is a time below the horizon. The time gate can be either above, below or span the horizon.

Occasionally, it is necessary to remove one or more poor spectral traces which contribute to the generation of the mean spectra. This is easily achieved by identifying problem spectral traces from the chart and deselecting these traces from within the Select Input Data Dialog.

Figure 4.22. Removing Bad Traces

If one or more seismic trace spectra displayed on the Raw Seismic plot were anomalous then it is possible to remove those traces from the Seismic Mean Spectrum calculation.

Let us imagine our Raw Seismic chart shows there is a trace with anomalous amplitudes that are biasing the mean. Now, if we wish to exclude this trace from the mean calculation, we must first identify it. This is achieved by pointing close to one of the vertexes of this spectrum and clicking on it. We need to be within few a pixels of one of vertexes to be able to identify it. If we are within range when we click then the spectra named, together with the Frequency and Amplitude of the vertex, is displayed in the Status Area of the Main Window. Suppose the raw seismic spectra is identified as "TRACE_036". We can now to go to the Input Trace list and click the checkbox to the left of entry "TRACE_036". This causes the trace to be flagged as not currently selected and the Raw Seismic plot on the Main Window is updated accordingly. The Seismic Mean spectrum (black) on both displays changes as a consequence. An alternative method, which works well in this case, is to look at the RMS Err property. So, if you sort by RMS Err, you will easily be able to identify any trace spectra with an abnormally large RMS Err value. You should note that once you toggled off a trace, it may loose its RMS Err value as the spectrum is not calculated.

The Select Volume dialog. Selecting a volume is done using the Blue Arrow mechanism from Petrel.

Figure 4.23. Select Volume

The image in the figure above show an example of the "Select Volume" Blue Arrow for selection of a seismic volume.

The Select SEGY Volume dialog provides you with a 3D SEGY file selector. From here you select the 3D SEGY file you require for your Frequency Shaping analysis and operators design. Unfortunately, selecting a 3D SEGY file for input here is not the end of the story. You need to also either select or build an offset mapping template for use with the selected SEGY file. Fortunately, within the software this is a straightforward task.

Figure 4.24. Select SEGY

...

The images in the figure above show examples of the "Select SEGY" dialog for selection of SEGY files and offset mapping. The LH image shows the dialog prior to opening a SEGY file. To open a SEGY file click the Open File... push button which will pop-up a file selector dialog allowing you to traverse the file system to select and open a SEGY file. The RH image shows that a SEGY file has been opened and has been matched with an offset Template. In this case, it was matched with the "Other 1" template. This dialog attempts to automatically match the opened SEGY file with one of the available templates. If the match is successful then the matched template will be highlighted and Min/Max Inline/Xline together with Start/End Time obtained from the Opened SEGY file will be displayed in the "Survey Area and Range Info" tab within the "Segy Summary" block. Similarly the opened SEGY file's EBCDIC header information will be displayed in the "Text Header" tab with the SEGY Binary header information being displayed in the "Binary Header" tab.

Now, if no template match is found then it will be necessary to create a new template. Fortunately, this is a relatively simple process and is achieved in the following manner. Select an existing template, it doesn't really matter which one you use, then click the Copy push button. Now select the new template which will appear at the end of the list of templates and will have a default name similar to "New Template 1". Finally click Edit... push button to pop up "Edit Template" dialog. Note that existing standard templates cannot be edited (OK button is greyed out), so make a copy first.

The Edit SEGY Template dialog provides you with a mechanism to edit SEGY templates. The original SEGY standard (rev 0) has been used extensively within the oil and gas industry as a convenient way to exchange seismic data between various companies. This standard was published in 1975 for storage of 2D line seismic data on magnetic tapes. Since this original publication there have been many advancements in geophysical data acquisition including disc recording and 3D seismic. The SEGY standard was subsequently used in ways that were never originally envisioned. Inevitably, this led to inconsistent use of the trace header attributes by different companies for storage of 3D seismic on disc. Whilst the SEGY standard (rev 1) published in 2002 was designed to address such issues, there is still a need to map (set up offsets) various trace header attributes as there is software and old SEGY files in existence that don't adhere to the new SEGY rev 1 standard.

Figure 4.25. Edit Template

The figure above shows the "Edit Template" dialog. This dialog allows you to assign a unique name and add a brief description. The main purpose of this editor is to allow you to set up the Template Offsets for mapping various trace attributes.

OK, let's look at how we set up the various Template Offsets. This dialog works with the opened SEGY file. Within the "Select Trace" block there is a slider and a spin box object. Both allow you to move to different traces within the SEGY file. Using these objects you can position the trace reader to any trace within the SEGY file. So for any trace you will be able to display the trace header data in the right panel beneath "Trace Header" label. By scanning the trace header for a given SEGY trace you should be able to determine where in the header various pieces of information are stored. So to edit the template offset we do the following:

Whilst ARK CLS recommends that when creating a new template all data items are mapped, it may be possible to generate a template without mapping every data item in the template offset list. We consider the most important items are "Inline", "Xline", "X Coord", "Y Coord", "Coord Scaler", "Start Time", "Number Of Sample", "Sample Interval" and "Trace ID Code". These "Data Items" in the "Template Offsets" list should always be set.

The Horizon Input Dialog provides you with a horizon selector. From the Horizon Data tab, simply select the horizon you require for your Frequency Shaping analysis and operators design.

Figure 4.26. Select Horizon

The image above shows an example of the "Select Horizon" dialog. Note that in the plug-in for Petrel variant the Horizon : push button allows you use the currently selected horizon in the Petrel input tree.

Loading acoustic impedance data from the OpendTect database is straightforward. The details are explained in the table beneath. Essentially, you click the Load Wells push button which will auto select all the acoustic impedance log curves in the OpendTect data repository.

Figure 4.28. Loading Well Logs from OpendTect

The images shows the top portion of the Input Well Log tab used to load OpendTect well log AI data.

Click the Load Wells push button which will auto select all the acoustic impedance log curves in the OpendTect data repository. It is assumed that acoustic impedance logs will have the characters "AI" (upper or lower case) or "IMP" (upper or lower case) somewhere within the log curve name. If, for a given well, there are no such AI log curves or the log curve doesn't meet the assumed naming convention, then the user can still select or generate AI log curves manually.

The image above also shows, in the central area, that two AI log curves, one each from two wells, have been automatically loaded. In OpendTect, log curves are stored in depth. Frequency Shaping requires the AI log curves to be in time. During the loading process the AI data which is stored in depth within OpendTect is depth to time converted using the associated time-depth model associated with a given well. It is then resampled to be regular in time. The sample interval used for this purpose can be changed via the Time Domain tab on the Advanced Controls dialog.

We can also manually select or generate AI well log. This is achieved by right clicking on well name which will pop-up a menu with "Select AI Log..." and "Generate AI Log..." menu items. Selecting the first item will pop-up the "Select Database Logs" dialog which lists the available logs allowing you to choose an AI log curve however it's named. Selecting the second item will pop-up the "Generate AI Log" dialog which displays two lists. The left hand list allows you to select a sonic log with right hand list allowing you to optionally select a density log. If no density is available, then you can select User for Density Source radio button and supplying a User Density Value. Here the AI log will be generated from the supplied sonic and density.

The push buttons "Clear Wells" and "Clear Unselected Wells" are self explanatory. The "Reshow Wells" push button will re-display any of the wells/logs cleared via the Clear Wells and Clear Unselected Wells push buttons. Note the Load Wells push button will change to a Reload Wells push button after the initial automatic selection. The Reload Wells push button will reload from the database all the currently available wells. In this way any new data loaded to the database will be displayed.

3.2.1.1. Select Well Logs Dialog

This dialog allows you to select the Acoustic Impedance Well Log data that is to be used from the OpendTect data repository.

Figure 4.29. Select Well Logs

This dialog provides a wild card filter field which operates on the list of logs to provide a facility to shorten the list of logs to a manageable size should this be necessary.

3.2.1.2. Generate AI Log Dialog

This dialog allows you to generate an Acoustic Impedance Well Log curve from the sonic and optionally, density logs that are stored in the OpendTect data repository.

Figure 4.30. Generate AI Log

This dialog provides wild card filter fields which operate on the two list of logs to provide a facility to shorten the list of logs to a manageable size should this be necessary. If no density log is available then you can supply a constant density value. This is achieved by clicking on "User" for the Density Source radio button and specifying the density value in the "User Density Value" field.

Loading Acoustic Impedance data when Frequency Shaping is a plug-in for Petrel is straightforward.

Figure 4.31. Petrel Well Log Selection

The picture above shows the Input Well Logs tab when using this tool as a plugin to Petrel*.

Select a well folder or individual well log in the Petrel input treee then click the Well Log: push button to add well logs for use within the application. The logs that are loaded are dependant on the current selection with the Petrel input tree. Only well continuous logs that have a valid depth-time relationship set up in the Petrel software will be loaded:

Single log: If a single continuous log is currently selected in the Petrel input tree, it will be shown in the input well logs "Field/Wells/Logs" table and will be selected by default.

Multiple logs: If multiple logs are currently selected within the Petrel input tree, those representing continuous logs will appear in the table, but will not be selected by default.

Wells: If wells or well folders are selected in the Petrel input tree, they will be searched, and all continuous logs with units suitable for Acoustic Impedance will be loaded into the "Fields/Wells/Logs" table.

The image above shows, in the central area, that two logs have been loaded from four wells. Wells can be selected or deselected for use within the Frequency Shaping application by clicking on the appropriate checkbox within the well/log list.

The Well Log: push button can be used to either add additional well logs or to reload an existing well log in the case that data has changed in the Petrel project.

The push buttons Clear Wells and Clear Unselected Wells can be used to remove all or some well logs from the well/log list.

Loading Acoustic Impedance data when Frequency Shaping is connected to the OpenWorks database is straightforward.

Figure 4.32. OpenWorks Well Log Selection from Synthetic Seismic in Time

The picture above shows the Input Well Log tab when connected to OpenWorks and when Acoustic Impedance logs are loaded as synthetic seismic traces in time.

The image in the figure above shows the Input Well Log tab, used to load OpenWorks well log AI data. The image shows the "Convert Logs in Depth to Time using Preferred Time Depth Curve" check box is un-checked meaning that AI logs in time stored as synthetic seismic will be read from the database. Click the Select Wellset... push button to pop up "Select Wellset" dialog (see Section Wellset dialog below). If no well data has been previously selected then clicking the Load Wells will also pop up the "Select Wellset" dialog.

From the "Select Wellset" dialog highlight the Wellset you require and click the Select push button. This will cause all AI data logs which have the specified naming convention to be automatically loaded but not selected for the OpenWorks Wellset. You can then select from the list the AI data logs you wish to use in the analysis.

It is assumed that acoustic impedance logs will have the characters "Imp" (upper or lower case) somewhere within the log curve name or "Impedance" (upper or lower case) in the remark field. If, for a given well, there are no such AI log curves or the log curve doesn't meet the assumed naming convention, then the you can still load AI log curves manually.

The image shows, in the central area, that three AI log curves, two for the ALB-HT-X1 well and one for the ALB-HT-X2 well, have been automatically loaded. Here we have selected one AI curve from just one well.

We can also manually select AI well logs. This is achieved by right clicking on the well name which will pop-up a menu with Select AI Log... Selecting this item will pop-up the "Select Database Logs" dialog which lists the available logs allowing you to choose an AI log curve however it is named.

Figure 4.33. OpenWorks Well Log Selection when Converting Logs from Depth to Time

The picture above shows the Input Well Log tab when connected to OpenWorks and when Acoustic Impedance logs are loaded as logs in depth and converted to time using the interpreter's preferred depth to time curve.

The image at left show the alternate OpenWorks situation where AI logs are loaded from depth logs which are automatically converted to time using the interpreter's preferred time depth curve.

The check-box "Convert Logs in Depth to Time using Preferred Time Depth Curve" is checked which enables the selection of an interpreter using the "Select Interpreter..." push-button. After the selection of the Wellset (see above in the Synthetic Seismic case) a window pops up that displays a list of interpreters for the project. Following the selection of the Interpreter the list will be populated with logs that have been converted from depth to time using the Interpreter's preferred time depth curve. If no logs are converted for a particular well a warning will be displayed. See section Select Interpreter dialog below.

3.2.3.1. Select Wellset dialog

The Select Wellset dialog provides you with a well set selector. From here simply select the well set you require for your Frequency Shaping analysis and operator design. A well set filter is provided to reduce the list to a manageable size for projects with many well sets.

Figure 4.34. Select Wellset (OpenWorks connected variant)

The image in the figure above show an example of the "Select Wellset" dialog for selection of an OpenWorks well set.

3.2.3.2. Select Interpreter dialog

The Select Interpreter dialog provides you with a list of available interpreters for the project. This will be used to find the Preferred Time Depth Curve for each well in the wellset. Wells that do not have a Preferred Time Depth Curve for the selected interpreter cannot be time converted and therefore will be omitted from list of available wells. A warning message box pops up in this situation.

Figure 4.35. Select Interpreter (OpenWorks connected variant)

Example of a "Select Interpreter" dialog to select an OpenWorks interpreter.

3.2.3.3. Select Database Logs dialog

The Select Database Logs dialog provides you with an Acoustic Impedance log selector. Here you can select any database log, in time, irrespective of how it is named. An acoustic impedance log filter is provided to reduce the list to a manageable size should there be many logs for the well.

Figure 4.36. Select Database Log (OpenWorks connected variant)

The image in the figure above shows an example of the "Select Database log" dialog for selection of OpenWorks impedance logs in time. Note only one AI log can be selected at a time. This window is reached by right-clicking on a well in the Field/Wells/Logs list.

Loading Acoustic Impedance data from ASCII is straightforward. Simply click on the "Load ASCII Wells..." push button to pop up a file selector. Within the File Selector you can traverse the file system to locate Acoustic Impedance data in ASCII format. The File Selector allows one or more ASCII files to be open at once. Use the Shift key modifier to select consecutive files and the Ctrl key modifier to select non-consecutive files from within the File Selector dialog. You can also mouse left click and drag the mouse over a number of ASCII files.

Figure 4.37. ASCII Well Log Selection

The image in the figure above shows the Input Well Log tab, where well log data has been loaded. In this case the well log data was loaded from ASCII files. The central list area shows four impedance curves have been loaded. One each for four wells. Normally, well log ASCII data files do not contain inline, xline or horizon data. So, in such cases, it is not possible to select a time range relative to an interpreted horizon. However, Frequency Shaping recognises certain XML style meta tags, which can be used by you to provide additional data. Below are the five XML style meta tags recognised by Frequency Shaping.

<inline>inline data here</inline>

<xline>xline data here</xline>

<horztime>horizon time data here</horztime>

<xcoord>x coordinate here</xcoord>

<ycoord>y coordinate here</ycoord>

These XML meta tags are normally inserted on one line within the ASCII file. For example, in Landmark style ASCII files these would normally be placed on the second line (which is blank). It is not necessary to include all the meta tags. Normally, only the <inline> and <xline> meta tags are supplied as there is then sufficient information for horizon data to be extracted from the supplied horizon. In this example, the horizon information for well_4.dat, well_3.dat and well_3.dat can be obtained from the supplied horizon (Horz Scr = horz) using the In-line and X-line data supplied via the meta tags <inline> and <xline>. For well_1.dat however, the horizon information comes from the <horztime> meta tag (Horz Scr = well) since no In-line or X-line data has been supplied.

Also, you can configure each well position manually by using the "Configure Well Position..." option when you right click on the top of a well log. Within the Configure Well Position dialog you can set the well position in terms of X/Y coordinates or Inline/Crossline values.

Figure 4.38. Configure ASCII Well Log Position

This section describes how you can define the format for ASCII file reading of well AI log data. Clicking the "Define Format..." push button will pop up the "Define ASCII File Format" dialog.

Figure 4.39. Define ASCII File Format

The figure above shows the "Define ASCII File Format" dialog. This dialog has three groups: "Select ASCII Format", "Record and Column Information" and "File Time Column Units".

Select ASCII Format: This group contains a radio button with two options "Landmark ASCII" and "User Defined". In "Landmark ASCII" mode(default) the other two groups are desensitised. In "User Defined" mode you can supply additional information in the "Record and Column Information" and "File Time Column Units" groups. Although no explicit LAS input facility is provided, you can normally read LAS files in "User Defined" mode.

Record and Column Information: If your ASCII has header records before the wireline curve data you should skip these by specifying a value in the "No. of Recs to Skip" input field. You should also specify which column the time data and the impedance data can be found. By default, these are set to 1 and 2 respectively.

File Time Column Units: This radio button item allows you to specify whether the time data is in milleseconds or seconds.

Specifying the time range (gate) is an important step. Ideally, you should choose a time gate in the range of 500 - 1000 msec which should be over the zone of interest. You can set the Time Range mode in one of three ways via the "Range" radio button.

Of the three options the Horizon Range mode is the preferred mode since it allows the gate to follow the geology.

Figure 4.40. Modify Well Log Time Range (Full)

The figure above shows the application main window with the "Select Input Data" dialog superimposed. Here, "Full" (full trace range) has been selected for the Range radio button. This mode is rarely used since our goal is to design Low End and High End operators over the zone of interest. This will optimise the process over that zone. However, it does allow you, although insensitive, to see the start and end times of the entire trace.

Figure 4.41. Modify Well Log Time Range (Sub)

The figure above shows the application main window with "Select Input Data" dialog superimposed. Here, "Sub" (sub trace range) has been selected for the Range radio button. In this mode the Absolute Start time and the Absolute End time Line Edit fields will be sensitised. This allows you to specify a time gate for the zone of interest. Typically, you would specify a time gate which has a time range between 500msec and 1000msec.

Figure 4.42. Modify Well Log Time Range (Horizon)

The image in the figure above shows the application main window with "Select Input Data" dialog superimposed. Here, "Horizon" (horizon relative trace range) has been selected for the "Range" radio button. In this mode the Relative Start time and the Relative End time Line Edit fields will be sensitised. This allows you to specify a time gate for the zone of interest. Typically, you would specify a time gate which would give you a time range between 500msec and 1000msec. Specifying the Start and End times here are relative to a geologic horizon. A negative number represents time above the horizon whereas a positive number is a time below the horizon. The time gate can be either above, below or span the horizon. Clicking the "Select Horizon..." push button will pop up the "Horizon Input Dialog".

Figure 4.43. Modify Well Log Time Range (Well Markers)

Note the Well Markers option is not available when connnected to OpenWorks.

The image in the figure above shows the application main window with "Select Input Data" dialog superimposed. Here, "Markers" has been selected for the "Range" radio button. In this mode the Relative Start time and the Relative End time Line Edit fields will be sensitised. This allows you to specify a time gate for the zone of interest. Typically, you would specify a time gate which would give you a time range between 500msec and 1000msec. Specifying the Start and End times here are relative to the well marker. A negative number represents time above the well marker whereas a positive number is a time below the well marker. The time gate can be either above, below or span the well marker. Clicking the "Select..." push button will pop a dialog with all the well markers common to the selected well logs and respective time values.