D Exponent Calculator

Penetration Rate (R) = Ft / Hr
Rotary Speed (N) = Rev / Minute
Weight on Bit (W) = 1000 Lb
Drill Bit Diameter (D) = Inches
Mud Weight Equivalent (Pn) = Lb / Gal
Mud Weight Used (Pm) = Lb / Gal
Shale Compactibility Coefficient (C) =  
d-Exponent value =

Formula
      d = [ (log ( R / (60 × N) ) / log ( (12 × W) / (1000 × D) ) ] × ( Pn / Pm )c
Where,
d = d-exponent value
R = Penetration Rate
N = Rotary Speed
W = Weight on Bit
D = Drill Bit Diameter
Pn = Mud Weight Equivalent
Pm = Mud Weight Used
C = Shale Compactibility Coefficient
Use this simple online D Exponent calculator to detect transition from normal pressure to abnormal pressure.