The AVOlite software is used to display and process log data and borehole seismic data.
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||Last updated: 16-Mar-2016 (version 5118)|
This software has been tested on Windows-10 and Windows-7.
The AVOlite software requires that the Microsoft Visual C++ 2013 Redistributable (x86) is installed on the PC before it will run. This can be downloaded from https://www.microsoft.com/en-sg/download/details.aspx?id=40784. Select the download for vcredist_x86.exe.
To install the AVOlite software, first install the vcredist_x86.exe as described above, then get the AVOlite_installer EXE file and run it.
After installation, it can be found under Program Files (x86) in the StarSeis directory.
Some quick user hints
1. Data Loading
To load data, click the File tab to see the drop-down main menu. The type of files that can be loaded include LAS file, ascii (text) files, waveform files and grid files. For more details on the ascii file options, see section 6 below. An example below shows the main page after loading an LAS file.
2. Log Plot Window
Click on “Plot” button on the top line. Following is an example of how to make a plot.
- Click on the AddPlot buttons to add extra plotting panels. The InsertPlot of DeletePlot buttons can also be used as required.
- Click on panel that you want to setup. This will now show all the curves currently in this panel.
- Click on curve you wish to add.
- Click Add.
- Click Plot to make the plot.
- A curve can be removed by selecting them in the lower table and click on “Delete DT2” in the curve selection panel. The curve name (DT2, in this example), was appended to the “Delete” after the curve had been selected for deletion.
- Multiple curves can be added to the same track. The scale displayed comes from the first curve. But you need to check that the scales chosen to display the other curves are compatible with that scale.
- The track width can be adjusted as desired. The widths should all add to 1.0, so they fill the form.
- The track title can be adjusted as desired.
- The plot title can be edited as desired.
- All columns in the tables are resizable to allow easy viewing and editing.
- Click on the Plot button in the curve selection panel to display the plotted data. An example plot is shown following.
- To make a copy of the plot, for pasting into another document:
- Color->White to make background white. (optional)
- File->Copy Form to Clipboard
- Use Paste inside Word or Powerpoint to paste the figure into a document
3. Crossplot Window
Click on Cross Plot button on the top line.. Following is an example of how to make a crossplot
- Select an X channel from the drop-down list
- Select a Y channel from the drop-down list
- Select a Z channel from drop-down list, and then choose color scaling for the Z channel.
- Click the XPLOT button.
Some features include:
- Can plot an overlay curve if required
- The FIT button attempts to fit a curve to the data.
- If fit a linear curve to the VP – VS data in a crossplot, the parameters can be copied directly into the VP from VS computation in the Log Utility window, by clicking CopyVS.
- If fit a power curve to the VP-RHOB data in a crossplot, can copy the parameters to the Gardner formula in the Gardner computation in Log Utility window, by clicking CopyGardner.
- The X, Y and Z channels have to have the same Start, Stop and Step. If not, the plot is not made. This constraint doesn’t apply to the Logplot window. If you want to crossplot data that have different start and stop, use the Cut facility in Log Utility to make them the same. Can also go Edit->Parameters and open up the tolerance to force a crossplot to be made., but the crossplot will not be exactly correct anymore, since data is misaligned.
- If both the Log plot and Crossplot windows are active, then they are synchronized in depth. For example, if select a depth interval in the Logplot window, only this interval is displayed on the crossplot. If scroll the depth of the Logplot window, the Crossplot will update to the new depth being viewed.
4. Log Utility window
Used for functioning data. As an example,
- Open Log Functions menu
- Click on Multiply, and input selection and parameters appear
- Select input channels and set parameters A and B as required
- Click GO.
Some points to note:
- If only select one input channel in Multiply, then this single channel is scaled by A only.
- These functions generally only work for data in the DEPTH list, but there maybe a few exceptions. For example, “Interpolate from Index logs” takes a depth channel and a log channel from the Index list and resample to 0.5” and writes into the Depth list.
- Clicking on the “Log Utility” button will generally cause the DEPTH channel list to pop up by default. If you want to process channels from the TVD or INDEX, click on this list after clicking on the Log Utility button.
- Delete, will delete all channels between the first and last selected channels. If only select one channel (ie, last is empty), then only one channel is deleted.
- After clicking GO, all parameters are reset.
5. Data Storage Overview
There are 4 main data types:
- Regularly sampled log data: a single array of numbers for each data channel. These data types are referenced from the “Depth”, “TVD” or “Time” sheets. The single index is either in depth or time. The depth and time index are similar; the index values are not specifically stored, but instead, the first, last and increments of the index are stored, the specific value of the index (eg, depth) is determined for the data sample, by knowing the sample number. The data in these files are in sequential, equally spaced order. They can be stored in either increasing or decreasing index direction. When the data is loaded, it is assigned into a “group” (either A, B, C…etc). Each group has the same start, stop, rate and number of samples. Generally, when functioning data, both input channels have to come from the same group.
- Irregularly sampled log data: a single array of numbers for each data channel. This data type is referenced from the “Index” sheet. Unlike the regular sampled data above, this data can be stored in any order, and with random sampling rates. Generally, to make use of this data, a second data channel that is similarly irregularly samples is required. An example is a VSP depth - transit time pair. The group concept is used here also but with further enhancement. One channel in a group is assigned the “group depth”, and is labeled with an asterisk. This assignation is done automatically in most cases, but can be set manually by going LogUtilities->Rename with Advanced option checked. If a data channel is plotted (ie Transit Time), then the channel that is assigned as the “group depth” (eg, “Depth”) is used to plot the transit time. Quite often, it may be desirable to change the “group depth” to Shot Number.
- Waveform data: Multiple dimensional arrays of numbers for each data channel. These files typically have distance as the first index, and either time or depth as the second index. This data types is referenced from the “WF” sheet.
- Property Grid File: Similar to waveform data, but specifically use to store material properties, for an earth model. The files are either 2D with X and Z coordinates, or 3D with X, Y and Z coordinates. For a 2D file, the single Y coord is always zero. This data types is referenced from the “PGF” sheet.
6. Loading and Saving data
Load LAS. Loads LAS file metres or feet automatically.
Load ASCII . Loads ASCII formatted data. Use the depth or time load option depending on the index of the data. The regular and irregular load options will load the data in to the appropriate data structure. No check is done to determine if the data has been loaded into the correct structure.
The ASCII file structure is shown following, where n = number of channels or columns of data in the file. Make certain there are no blank lines after last line of data, else may give errors during load. If a channel doesn’t have a unit name (eg, shot number), then must use a dummy name such as “x” or “.”. The first column should be either depth or time.
n NAME1 NAME2 .... NAMEn UNIT1 UNIT2 .... UNITn 2000 3.64 3.566 ... 2.556 2001 3.56 5.455 ... 5.444 .. .. 2045 3.33 1.333 ... 5.444
For best results. After loading data, you should FLIP logs so they run Top -> Bottom. If the log sheet is yellow, it means there is data that goes from deep-to-shallow. If it is green, then all the data is going from shallow to deep.
It may also be desirable to “cut” logs so they all have same START, STOP and STEP, then SAVE SESSION. After cutting logs to the same depths, they will be assigned to belong to the same group.
LAS files are always regularly sampled. ASCII files, or LDF header dumps may be irregularly sampled. For some applications, it may be nessecary to interpolate this data to a regular sample rate with same START, STOP and STEP as other data. This can be done in the Log Utilities->Resample data.
Log data can be saved into ASCII files, however, only the data from one group (ie. data that has the same start, stop and step parameters) can be saved at one time. To save data, first click on one of the channels in the group of data to be saved, then when click save, all data in that group will be written to ASCII file.
Waveform data can be loaded from either LDF or SEGY data files. Since SEGY is not a standard format, then may not be able to read all types of SEGY files.
The waveform data channels can be saved back into either LDF or SEGY files, however, by default, the “save” option for SEGY files is not allowed. To save waveform files, click on the waveform channel name, then run the appropriate “save” task .
"Save Session" saves all log, waveform, PGF data currently in memory to a binary file. This file can later be re-loaded using "Load Session". When processing data, it is good to frequently save the session, so that can easily return to a previous step if required. Huge PGF’s will limit how often you will be able to do this!.