Page 236 - Air and Gas Drilling Manual

5-78 Air and Gas Drilling Manual



1
f =

.
.

2 log  1 021 − 0 458   + 114      2
.
   0 0042   
.
.
f = 0 034
Equations 5-17 and 5-18 become, respectively,
.
a = 10
i
53 36
.
a = 0 019.
i
and
.
1 366)
b a = 0 034  53.36  2 (. 2
π
.
.
2 32 2) ( 1 021 − 0 458. )  1 0.    2 [ ) 2 ) 2 ] 2
(
  (1 021. − (0 458.
4
.
b a = 11 8
Equation 5-16 becomes
  2 (. 0 019 ) ( , 2 400 )   . 05
 (, 5 421 ) 2 + ( . ) (523 .54 ) 2 e  523 .54 −  1 
11 8
    

P in =   2 (. 0 019 ) ( , 2 400 )  
 e 523 .54 
 
 
2
,
P in = 5 026 lb/ft abs
P in
p in =
144
p in = 34 9 psia
.
The above pressure is the approximate injection pressure into the top of the
borehole annulus. In these calculations the drill collar outside diameter is neglected.
Also, the calculations have ignored the friction losses in the surface flow line