Page 332 - Air and Gas Drilling Manual
P. 332
Chapter 8: Air, Gas, and Unstable Foam Drilling 8-15
π
π
2
2
e
eDH
h
oh
p
p
4
4
=
e
π
π
avo
2
DH
DH o o + + 2 p DH o
o
h
4
4
The term H o cancels and the above reduces to
π
π
e D 2 + e D 2
oh h p p
4
4
e = (8-2)
π
π
avo
2 + 2
D h D p
4
4
Thus, e avo, is
π
π
2 2
1
0
00
0
(. ) (.656 ) + (.0 00015 ) (.375 )
e = 4 4
π
π
avo 2 2
(. 0 656 ) + (. 0 375 )
4
4
e avo = 0 0076 ft
.
Equation 6-58 becomes
2
f = 1
ao 0 656 − 0 375
.
.
2 log +114
.
0 0076
.
.
f ao = 0 055
With the above values Equations 6-52 and 6-53 become, respectively,
a ao = 10. 1 + 0 950.
53 36. 2 019.
.
a ao = 0 028
and
