Page 348 - Air and Gas Drilling Manual

Therefore, Equation 6-58 becomes
2


  Chapter 8: Air, Gas, and Unstable Foam Drilling 8-31
f a1 =   0 668 − 1 0 375   
114
2  log  . .  + .

   0 00015   
.
.
f = 0 017
a1
With the above values Equations 6-52 and 6-53 become, respectively,
0 950  
 10    .
.
a a1 =  53 36    1 +  .  
2 635 
.
.
a a1 = 0 025
and
2 635)
.
.
b a1 = 0 017  53 36  2 (. 2
0 668 −
π
.
.
(
2 32 2) ( . 0 375  ) 10    2 [ 2 2 ] 2
.
0 668)
0 375)
 4  (. − (.
.
b a1 = 304 7
Equation 6-57 becomes
  2 0 025) ( , 6 650)  05 .
(.
[
2 
.
P a1 =  ( , 2 + 304 7 537 66) 2 ] e 537 66 − 304 7 537 66 
.
)
. (
. (
2 164)
.
   
2
,
P a1 = 9 285 lb/ft abs
P a1
p a1 =
144
.
p a1 = 64 5 psia
The second annulus seciton increment is denoted by the length H 2. The
temperature at the bottom of the length H 2 in the cased annulus section (bottom of
the drill pipe tool joints lumped geometry), T 2, is