Page 183 - Air and Gas Drilling Manual

Chapter 5: Shallow Well Drilling Applications 5-25
Thus, P g and T g become
2
P =
,
g
T = P at at = 1 695 lb/ft abs
o
.
= 529 67 R
T
g
Using Equation 4-11, the specific weight of the air entering the compressor is
(1 695, ) (1 0. )
γ =
g
(53 36. ) (529 67. )
γ = 0 0600 lb/ft 3
.
g
The volumetric flow rate of air entering the top of the compressor, Q g, is
Q g = 840
60
3
.
Q g = 14 0 ft /sec
The weight rate of flow of air in the circulating system in the well is
( . )
˙ w = . 0 0600 14 0
g
˙ w = . 0 840 lb/sec
g
The borehole diameter, D h, is

.
d h = 475 inches
d
D = h
h
12
D = 0 396. ft
h
Using Equation 5-4, the weight rate of flow of the solid rock cuttings in the annulus
is
π
   30 
2
.) ( . ) 
˙ w = (. 0 396 ) (62 4 3 0 
s     (60 ) (60 )  
4