Page 451 - Air and Gas Drilling Manual

Chapter 9: Aerated Fluid Drilling 9-55
assuming this Reynolds number approximates the flow conditions throughout the
inside of the drill collar section.
Using Equation 4-11, the approximate specific weight of the gas as it enters this
drill collar section is determined from P i5. This is
,
.
( 612 640) ( 1 0)
gi5
.
.
( 53 36) ( 601 91)
19 07 lb/ft 3
.
gi5
Using Equation 1-2, the density of the gas as it enters this drill collar section, gi5 ,
is
19 07
.
gi5
.
32 2
lb sec 2
.
0 592
gi 5 4
ft
From Equation 9-7, the kinematic viscosity of the gas at this location, , is
gi5
.
0 000000251
gi5
.
0 592
2
ft
0 000000423
.
gi5
sec
The average kinematic viscosity of the mixture as it enters this drill collar section,
, is
avi 5
( 1 282)( 0 000000423) ( 31 92)( 0 0002691)
.
.
.
.
avi 5
.
.
1 282 31 92
2
.
0 000259 ft /sec
avi 5
Using the inside diameter of the drill collars, D 5, the approximate average
velocity of the aerated drilling fluid as it enters this drill collar section, V i5, is
.
,
1 826 6 . 601 91
(. 0 426
.
19 47)
,
.
612 640 519 67
V i5
0 234 2
.
4