Output of ABAQUS for contact of a rigid surface with a poroelastic layer

Hello, I am modeling the spherical indentation of a poroelastic layer. I am modeling the indenter as a rigid analytical surface. As you know, the total pressure in a porous medium at each point is the sum of the elastic stresses from the matrix, and the pore pressure caused by fluid pressurization. Abaqus provides both the pore pressure and of course the rest of the stress quantities.

As I'm analyzing an indentation problem, my final result needs to be a force quantity (spherical indenter thus non-constant area), or I need to be able to convert the stresses to force by having some knowledge of the area. There are a few outputs that look interesting to me for this purpose, but all correspond with elastic stresses it seems, and not the pore pressure. So if I were only dealing with elastic stresses, I could use CFORCE (CNF2) and sum over nodes for which contact is closed, or alternatively use CFN which is a whole surface output and is the total force due to contact pressure.

 These values don't show any stress relaxation however, so it makes me believe that they are not the actual "total" but just the elastic part of the stress tensor. I can't use the pore pressure values and get the force resulting from that part because the problem then becomes converting the pressure to force. I see two output quantities for areas but they don't seem to be useful: CAREA is the "total" area in contact so that won't help because pore pressure varies across the surface. The other is CNAREA which is the "contact nodal area" which is only available for the master surface. This still looks like the most useful to me, but I am not finding any description in the documentation more in-depth than that. Is this the effective area at each node, so that if I multiply the pressure by this and sum over all nodes, I will get what I need (sort of)? I say "sort of" because although the horizontal components cancel out overall (due to symmetry), since I'm looking at each node individually then I will also need to be able to project this onto the z axis for each node.

I'm basically looking for a way to convert the simulation output to force so that it can be compared with the experimental results. Does anyone have an idea/experience with this?

Thanks!