About the SEED with porosity

Hi, everyone

I'm using TOUGHREACT1.2/ECO2N with Petrasim,and i found that in Petrsim can set different porosity for each cell in "Set cell data", so I wonder how can I achieve that by text manipulation. i found that in TOUGH2 MANUAL it says the SEED function can generate random fields for permeability, but what about porosity?

I hope someone can tell me, thank you all ！