Page 435 - Air and Gas Drilling Manual

T
T
1
2
T
2
T av2 572 66.˚R Chapter 9: Aerated Fluid Drilling 9-39
av2
In order to obtain the approximate value of the Fanning friction factor for
Equation 6-74, it is necessary to estimate the Reynolds number and, thus, the flow
conditions in the cased annulus section along H 2. This is accomplished by
determining the Reynolds number at the exit end of this annulus section and
assuming this Reynolds number approximates the flow conditions throughout the
annulus section.
Using Equation 4-11, the approximate specific weight of the gas as it exits this
cased annulus section and starts into the annulus section above is determined from
P a1. This is
,
.
( 268 632) ( 1 0)
ga2
.
.
( 53 36) ( 572 66)
879 lb/ft 3
.
ga2
Using Equation 1-2, the density of the gas as it exits this annulus section, , is
ga2
879
.
ga2
.
32 2
2
lb sec
0 273
.
ga2 4
ft
From Equation 9-7, the kinematic viscosity of the gas at this location, ga2 , is
0 000000251
.
ga2
.
0 273
ft 2
0 000000918
.
ga2
sec
The average kinematic viscosity of the mixture at this position, , is
ava1
0 0002691)
1 282)( .
( . 0 000000918) ( 31 92)( .
.
ava2
.
.
1 282 31 92
2
0 000259 ft /sec
.
ava2