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Skin Factor Calculator

Calculate wellbore skin factor from near-wellbore permeability damage or stimulation. Quantify damage severity and estimate productivity improvement from workover.

Hawkins' Skin Formula

Undamaged Permeability, k (md)

Damaged Zone Permeability, k_d (md)

Damage Zone Radius, r_d (ft)

Wellbore Radius, r_w (ft)

Results

Skin Factor S

Damage Ratio k/k_d

Flow Efficiency

Equations

Hawkins' formula: S = (k/k_d - 1) × ln(r_d/r_w)

Interpretation: S > 0 = damage; S < 0 = stimulation (frac or acid); S = 0 = no skin.

Flow Efficiency: FE = (P̄_r - P_wf - ΔP_skin) / (P̄_r - P_wf)

Skin from FE: S ≈ (1/FE - 1) × [ln(r_e/r_w) - 0.75]

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Skin Factor Calculator

Hawkins' Skin Formula

From Flow Efficiency

Results