Patent ID: 8862407

Claim:
A method of calculating critical cut-off transverse relaxation time T 2oc for a formation, comprising: obtaining an indication of permeability k for the formation at a depth using a fluid injection measurement, a fluid drawdown measurement, or both; and using a processor to calculate a critical relaxation time T 2oc according to T 2 ⁢ oc = 2 ⁢ 2 ⁢ k ϕ ⁢ ⁢ ρ ⁢ ⁢ T 2 ⁢ b + 2 ⁢ 2 ⁢ k ⁢ T 2 ⁢ b , wherein ρ is the surface relaxivity at the depth, φ is porosity at the depth, and T 2b is bulk transverse relaxation time of the fluid.