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##Simple Oil Drilling Calculations

Bunch of scripts (more to come, I hope) for calculations used in oil drilling. Calculations are, mostly, based on the book "Formulas and Calculations for Drilling, Production and Workover" by William C. Lyons Ph.D. P.E., Thomas Carter, Norton J. Lapeyrouse.

Calculates annular velocity of the fluid while pumping. Three main factors affecting annular velocity are size of hole (bigger ID), size of drill pipe (smaller OD) and pump rate. This post will show you how to calculate annular velocity in feet per minute with different formulas.

Higher wellbore temperature will reduce the brine density more. The calculation demonstrates how to determine brine weight to mix on surface in order to get required brine density at a wellbore condition.

Calculates Cutting Carrying Index, which indicates quality of hole cleaning.

Drill collar provides weight to the bit for drilling and keep the drill string from buckling. Additionally, drill pipe should not run in compression because it can get seriously damaged.

Calculates equivalent diameter of pipe string, based on length and diameter of composing runs. Can be useful, sometimes.

Calculates pressure drop through Drill String.

Calculates required pressure to break gel strength after mud being in static condition (loss of circulation).

Calculates pressure required to perform Formation Integrity Test (FIT).

Calculates output of Duplex or Triplex HP Mud Pump, for given Efficiency.


All units are in *oilfield system - psi, feet, inch. Calculations can not be used in other unit system, without correction for units.


You are using these scripts on YOUR OWN RISK. Scripts are not replacement for simulations run by well control companies.

(c) D. Djokic, 2015

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