You can define the initial saturation, s, for a region in a coupled pore fluid diffusion/stress analysis (see “Coupled pore fluid diffusion and stress analysis,” Section 6.8.1 of the Abaqus Analysis User's Guide). You can create an initial saturation field only during the initial step.
To create or edit a saturation field:
Display the saturation field editor using one of the following methods:
To create a new saturation field, follow the procedure outlined in “Creating predefined fields,” Section 16.8.3 (Category: Other; Types for Selected Step: Saturation).
To edit an existing saturation field using menus or managers, see “Editing step-dependent objects,” Section 3.4.13.
Click the arrow to the right of the Distribution field, and select the option of your choice from the list that appears:
Select Uniform to define an initial saturation that is uniform over the region.
Select an analytical field to define a spatially varying initial saturation. Alternatively, you can click 
to create a new analytical field. (See Chapter 58, “The Analytical Field toolset,” for more information.)
From the Saturation field, specify an initial saturation value for the region between 0.0 (for no saturation) and 1.0 (for full saturation).
Click OK to create the saturation field and to close the dialog box.
Green squares appear on the model representing the initial saturation field that you just created.
