Strater 4 now has the ability to create a cross section from line/symbol logs. This is useful since a user doesn't always have lithology information (which previous versions required in order to create a cross section), but a cross section can just as easily be created from a line log like a Gamma Ray log. To create the cross section, you will need a collars table containing the location of your wells, and either a depth or interval table to be used in generating the actual cross section. An example of a depth log that can be used to generate a cross section can be found in the LAS Example-2.sdg file in the Samples directory. It's the table called LAS Data.
Follow these instructions to create a cross section from your own line log:
- In a new instance of Strater, load in your collars table and your depth or interval table.
- From the borehole view go to Map | Create Well Map.
- In the map view, select your map and go to Map | Add Well Selector.
- Click on your wells in order from left to right, double clicking on the last one. Hit ESC to exit digitizing mode.
- Click on your well selector line and then go to Cross Section | Create Cross Section.
- In the Import Or Select Data To Create Cross Section Logs dialog, change the Type of cross section logs to be created to Line/Symbol log. Click OK.
Your logs are loaded. You will notice that there are no layers loaded. The only time Strater 4 does not automatically construct layers is for cross sections generated from line/scatter logs, since there's a higher degree of complexity in picking the boundaries that depend highly on the type of data shown in the log. To get layers, you can choose any of three options in the Cross Section menu: Connect Logs with Layers, Import Layer Marks, or Manual Layer Marks. I'll show you how to use the Manual Layer Marks command here (you'll learn about Connect Logs with Layers in next week’s blog).
- Click on the Logs object in the Object Manager.
- Go to Cross Section | Layer Marks | Create/Edit.
- If you get your mouse near enough to a log, the borehole name and depth of your mouse on that log will be displayed. Click on the log at the location of your layer top and then either choose the layer's name from the dropdown list in the Name The Layer dialog box or type a new name. Click OK. To declare that your picks are the layer bottoms instead of tops, select the Layers object in the Object Manager, and then uncheck the box in the Property Manager next to Layer Line Marks Layer Top (you can do this before, during, or after creating your layers).
- Repeat step 3 for all layers in each of your boreholes.
- When you're finished, hit ENTER on your keyboard.
- In the Save Layer Marks To Table dialog, either keep the checkbox next to Save layer marks to table checked to write your layer top (or bottom) information to a table, or uncheck it. Click OK . Either way your lines representing your layer tops (or bottoms) will be created on your cross section.
- Click Yes to redraw your cross section.
This process will create multiple polylines for each layer (one between each pair of adjacent logs). To display layer polygons between each adjacent log, select the Layers object in the Object Manager, and then check the box in the Property Manager next to Fill between Layer Lines. Click Yes to redraw your cross section. Now, if you want, you can turn off the polylines under
the Layers object in the Object Manager, and then check the box in the Property Manager next to Show Layer Labels with Layers selected in the Object Manager to get an image like the one below.
NOTE: After creating your layers, you can go back to Cross Section | Layer Marks | Create/Edit to see your layer marks displayed on the logs and to edit them. To delete a mark, hover your mouse over the mark until the layer name displays in addition to borehole name and depth. Click on the mark and then check the box next to Delete this mark in the Update Layer Name dialog box. This is also where you can change the layer name for the mark.
NOTE: If you choose to display your cross section from line/symbol logs as deviated, your line/symbol log squiggles will straighten into a vertical line, since Strater doesn't know how to show squiggles as deviated.
NOTE:Strater only connects layers between adjacent wells if both wells contain the layer. It does not create pinchouts.