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Net Pay Calculator
Calculate net pay thickness from well log data using porosity and water saturation cutoffs. Fundamental to reserves estimation and well completion design.
Inputs
Log-derived porosity
From Archie equation or log
Typical: 0.05–0.12
Typical: 0.60–0.75
Shale volume cutoff
Results
Net-to-Gross
--
Net Pay
--
ft
Phi×h
--
ft
Phi×h×So
--
ft
Equations
Net Pay: Intervals meeting ALL cutoffs: φ > φ_cutoff, Sw < Sw_cutoff, Vsh < Vsh_cutoff
Net-to-Gross: NTG = Net_Pay / Gross_Pay
Phi×h: φ × Net_Pay (porosity-feet, input to OOIP)
Phi×h×So: φ × (1-Sw) × Net_Pay (hydrocarbon porosity-feet)
Note: This uses average properties; real NTG requires interval-by-interval log analysis.
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