After learning about **capacity calculation**, we can apply the capacity calculation to determine how much barrels of cutting produced per foot of hole drilled and total solid generated in pounds.

**Please read and understand the following formulas:**

Use formula#1 and #2 for calculating amount of cutting generated per feet drilled.

## Formula#1 for BARRELS of cuttings drilled per foot of hole drilled:

**Barrels of cutting per foot drilled = Dh ^{2} x (1 – % porosity) ÷1029.4**

Where: Dh is hole diameter in inch.

**Example: **Determine barrels of cuttings drilled for one foot of 6-1/8 inch hole with 25% (0.25) porosity:

Barrels/footage drilled = 6.125^{2} x (1 – 0.25) ÷1029.4

Barrels/footage drilled = 0.02733 bbl/footage drilled

## Formula#2 for CUBIC FEET of cuttings drilled per foot of hole drilled:

**Cubic feet of cutting per foot drilled = Dh ^{2} x 0.7854 x (1 – % porosity) ÷144**

**Where: Dh is hole diameter in inch.**

**Example: **Determine barrels of cuttings drilled for one foot of 6-1/8 inch hole with 25% (0.25) porosity

Cubic feet/footage drilled = 6.125^{2} x 0.7854 x (1 – 0.25) ÷144

Cubic feet/footage drilled = 0.153462 cu ft/footage drilled

Moreover, you also apply sample density and volume relationship to determine total solids generated. Use the following formula to calculate total solid generated.

**Wcg = 350 x Ch x L x (l – porosity) x Cutting density**

Where;

Wcg = solids generated in pounds

Ch = capacity of hole in bbl/ft

L = footage drilled in ft

Cutting density = cutting density in gm/cc

**Example:** Determine the total pounds of solids generated in drilling 100 ft of 6-1/8 inch hole (0.03644 bbl/ft).

Density of cuttings = 2.20 gm/cc.

Porosity = 25%:

Wcg = 350 x 0.03644 x 100 x (1 – 0.25) x 2.2

Wcg = 2104.41 pounds

**Ref books: **Lapeyrouse, N.J., 2002. Formulas and calculations for drilling, production and workover, Boston: Gulf Professional publishing.

Bourgoyne, A.J.T., Chenevert , M.E. & Millheim, K.K., 1986. SPE Textbook Series, Volume 2: Applied Drilling Engineering, Society of Petroleum Engineers.

Mitchell, R.F., Miska, S. & Aadny, B.S., 2011. Fundamentals of drilling engineering, Richardson, TX: Society of Petroleum Engineers.