Page 187 - Air and Gas Drilling Manual

g
a =
(5-8)
i
2
w ˙
g
b = S R f  R  2 Chapter 5: Shallow Well Drilling Applications 5-29
(5-9)
i   2
π
2 gD  S    4
g
i
  D i
4
The Fanning friction factor for the above equation is
  2
 
 
f =  1  (5-10)
  D  
i

+ 1 14
 2 log. 

   e   
p
Using the above values, Equation 5-10 becomes
  2
 
f =  1 
  0 166  
.
.
 2 log  + 114 
.
  0 00015 
.
f = 0 019
Equations 5-8 and 5-9 become, respectively,
.
a = 10
i
53 36
.
a = 0 019.
i
and
0 840)
.
b = 0 019  53.36  2 (. 2
π
i
2 322 . ) ( .  10 .    2 4
(
0166)
0 166)
  (.
4
b = 7 610
,
i
Equation 5-7 becomes