Determine free point constant (FPC)

Referring to the previous post, it is difficult to find drill pipe stretch table or there is no data available for you when you are really need it. This post will show you how to calculate free point constant (FPC) based on cross section of drill pipe, tubing or any cylindrical objects.

The free point constant (FPC) formula for any type of steel drill pipe is listed below:

FPC = As x 2500

where: As = pipe wall cross sectional area, sq in.

As = (OD2-ID2) x 0.7854

This method requires outside diameter and inside diameter data.

Example#1: Determine free point constant (FPC) of 4 in. drill pipe 14.0 lb/ft, inside diameter of drill pipe = 3.34 inch.

FPC = (42 – 3.342) x 0.7854 x 2500

FPC = 9512

Please find the Excel sheet to calculate free point constant.

Ref book: Drilling Formula Book Formulas and Calculations for Drilling, Production and Workover, Second Edition

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3 Responses to Determine free point constant (FPC)

  1. Ankesh Nagar says:

    Please increase the frequency of topics and how to wriggle out in worst case scenarios

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