I found a solution.
The OpenFoamReader doesn’t read the variables that are listed when calling the paraFoam utility in the default version of OpenFoam installation. The Reader used in paraFoam corresponds to the PVFoamReader. To use it, it was need in the pvpython it was needed to use the LD_PRELOAD, in the same fashion as described in this thread.
I just need to find the file and adjust the path. Hope this help someone! 