Click on the element "Fault" of the tree scene and select New... option as shown below.
This will insert a new fault {New Fault x} with a blank attribute. Insert the inline/crossline in the scene where you want to interpret the faults. Highlight the newly inserted fault in the tree and start interpreting a fault by clicking on inline/crossline. In OpendTect, the fault model is arranged in an ordered sequence of fault sticks that are picked on vertical planes (inlines/crosslines) and horizontal planes (time slices). Therefore, a user cannot pick a fault stick on a time slice if the fault already contains sticks that were picked on inline/crossline. The fault planes will be constructed according to the arrangement of the faults sticks. This is done to avoid crossings within the fault plane. Hence it is suggested to make a consistent interpretation i.e. either pick fault sticks on inlines/crosslines or only on time slices. When you are done, right click on the fault and select save. Write an appropriate name of the fault and leave the "Replace in tree" checked. Press OK. This will save and update the name of the interpreted fault. To continue fault picking on a next inline/crossline, a user can take benefit of the scrolling options available for inline/crossline/timeslices.
If a node has been interpreted mistakenly, press Ctrl (control) button down and click on the yellow node to remove it. In this way you can remove the unwanted nodes. To move the node position, use mouse to select and drag the seed. After editing/interpreting, please do not forget to save the faults to update the changes.
Fault tree pop-up menu items:
Add Attributes: The fault attribute in OpendTect works similar as other attributes. The selected attribute would be displayed on fault plane. It can be the original seismic, calculated attributes, or others. Up to eight (8) attributes can be inserted for one fault. In the tree, right click on the fault attribute and select the corresponding attribute from the list.
Show histogram: The histogram of the faults attribute can be displayed using this option. This allows the user to clip the range of a displayed attribute
Properties: The option allows to change the general material properties for fault i.e. color, reflectivity, and transparency.
Use single color: To display a fault plane in single color, select this option.
Display: Three display modes for faults are categorized in the tree. To display fault planes in 3D, select the Fault planes option in the sub-list. Otherwise, if option Fault sticks is selected, the interpreted sticks would be displayed in the scene. Or, if you want to display the faults only at sections (inline/crossline), select At sections only.
Save: This option will save the newly inserted/edited fault.
Save as: To save the fault with a new name.
Lock: It will lock the current fault.
Remove: This will only remove the loaded fault from the tree. Remember, it will not delete the fault from the project. To delete the fault, launch the Fault Management Window by pressing button in the manage toolbar.
The figure below is an example section with interpreted faults. The displayed attribute along faults is the original seismic. Notice that how the events would have been characterized along the fault plane. You can edit and adjust the fault planes by using the yellow nodes, CTRL/SHIFT keys and mouse click as described earlier.
Note: The fault interpretation has only been developed for 3D surveys. For 2D, only fault stick set are interpreted.
button in the manage toolbar.
