Page 47 - Air and Gas Drilling Manual

1-24 Air and Gas Drilling Manual
The average velocity of the drilling mud at this position is approximately 3.0
ft/sec. Using these values in Equation 1-1, the kinetic energy per unit volume for
the drilling mud example becomes
.
KE m = 1 (233 ) (30 . ) 2
2
ft − lb
.
KE m = 10 5 3
ft

Figure 1-22: Annulus velocities for drilling mud and compressed air.

For the air drilling example the specific weight of the compressed air in the
3
annulus just above the drill collars is 0.688 lb/ft . Using these values in Equation
1-2 the density of the compressed air is