It gives you an basic idea of D-Exponent and why it is introduced

1. D-Exponent
SYED NAWAZ
M.Tech Petroleum Exploration and Production

2. Content
• Introduction
• Limitations of D Exponent
• Modification in D Exponent

3. Introduction
• It is a method of correcting or normalizing ROP.
• The D exponent is the work of Bingham and
Jordan and Shirley

4. Mathematical representation
• ROP= Rate of Penetration (ft/hr)
• RPM= Rotation per Minute
• WOB= Weight on Bit (lbs)
• B= Diameter (inch)

5. Limitation of D Exponent
• The D exponent is proportional to rock strength
and for normally pressured formations, the D
exponent increases linearly with depth,
reflecting increased rock strength and depth.
• For abnormally pressured formation, the D
exponent deviates from the normal trend and
actually decreases with depth.

6. Modification in D Exponent
• A further modification of the D Exponent was
proposed by Rehm et al 1971 who attempted to
correct the D exponent for the effect of changes
in mud weight. The resultant equation for the
corrected D Exponent (dc)

7. Numerical approach

8. Limitation of D Exponent
• Increase in mud weight cause lower values of
corrected d exponent
• Corrected d exponent is effected by lithology,
unconformities in the formations, etc

9. Thank you