Calculate inner capacity of open hole/inside cylindrical objects

Calculate inner capacity of open hole/inside cylindrical objectsFrom the previous post, you learn how to calculate annular capacity and this post shows you how to use the same principle to calculate inner capacity of open hole / inside cylindrical objects such as tubulars, drill pipe, drill collars, tubing, casing etc.

There are several formulas to calculate inner capacity depending on unit of inner capacity required. Please read and understand the formulas below:

Formula#1) Calculate inner capacity in bbl/ft

Inner Capacity in bbl/ft = (ID in.)2 1029.4

Example: Determine inner capacity in bbl/ft of a 6-1/8 in. hole:Inner Capacity in bbl/ft = 6.12521029.4Inner Capacity in bbl/ft = 0. 0364 bbl/ft

Formula#2) Calculate inner capacity in ft/bbl

Example: Determine inner capacity in ft/bbl of 6-1/8 in. hole:Inner Capacity in ft/bbl = 1029.4 6.1252Inner Capacity in = 27.439 ft/bbl

Inner Capacity in ft/bbl = 1029.4 (ID in.)

Formula#3) Calculate inner capacity in gal/ft

Inner Capacity in gal/ft = (ID in.)2 24.51

Example: Determine inner capacity in gal/ft of 6-1/8 in. hole:Inner Capacity in gal/ft = 6.1252 24.51Inner Capacity in = 1.53 gal/ft

Formula#4) Calculate inner capacity in ft/galInner Capacity in ft/gal = 24.51 (ID in.)2Example: Determine inner capacity in ft/gal of 6-1/8 in. hole:Inner Capacity in ft/gal = 24.51 6.1252Inner Capacity in ft/gal = 0.6533 ft/gal

Determine the volume of mud to fill up the inner of the cylindrical objects by the following equation.Inner Volume = Inner Capacity x LenghtExample: Inner capacity = 0. 0364 bbl/ft

Length= 3000 ft

Volume =0. 0364 x3,000 = 109.2 bbl.

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