Page 543 - Air and Gas Drilling Manual

10-68 Air and Gas Drilling Manual
of this drill string section and assuming this Reynolds number approximates the
flow conditions throughout the inside this drill string section.
Using Equation 4-11, the approximate specific weight of the gas as it enters this
drill string section is determined from P i1. This is
.
,
( 190 555) ( 1 0)
gi2
.
.
( 53 36) ( 572 66)
624 lb/ft 3
.
gi2
Using Equation 1-2, the density of the gas as it enters this drill string section, gi2 ,
is
.
624
gi2
32 2
.
lb sec 2
.
0 194
gi2 4
ft
From Equation 9-7, the kinematic viscosity of the gas at this location, gi2 , is
.
0 000000251
gi2
0 194
.
2
ft
.
0 00000129
gi2
sec
The average kinematic viscosity of the mixture as it enters this drill string section,
, is
avi2
.
.
.
( 1 821)( 0 00000129) ( 14 60)( 0 00001078)
.
avi2
1 821 14 60
.
.
2
0 00000973 ft /sec
.
avi2
Using the inside diameter of the drill pipe tool joints, D 6, the approximate
average velocity of the aerated drilling fluid as it enters this drill string section, V i2,
is