d-Exponent Calculator

Enter value and click on calculate. Result will be displayed.

R = Penetration Rate
N = Rotary Speed
W = Weight on Bit
D = Drill Bit Diameter
n = Mud Weight Equivalent
m = Mud Weight Used
C = Shale Compactibility Coefficient

Enter your values:
Penetration Rate: Ft / Hr
Rotary Speed: Rev / Minute
Weight on Bit: 1000 Lb
Drill Bit Diameter: Inches
Mud Weight Equivalent: Lb / Gal
Mud Weight Used: Lb / Gal
Shale Compactibility Coefficient:

This concept was first developed by Jorden & Shirley This is a factor for evaluating drilling rate and predicting abnormal pore pressure zones.

All things being equal, the d-exponent should increase with depth when drilling in a normal pressure section. A reversal of this trend is an indication of drilling into potential overpressures.