Page 540 - Air and Gas Drilling Manual

Chapter 10: Stable Foam drilling 10-65
T
586 29˚R
.
av3
In order to obtain the approximate value of the Fanning friction factor for
Equation 6-102, it is necessary to estimate the Reynolds number and, thus, the flow
conditions inside the drill pipe body lumped geometry along H 3. This is
accomplished by determining the Reynolds number at the entrance end of the inside
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 i3. This is
,
( 273 856) ( 1 0)
.
gi3
.
.
( 53 36) ( 586 29)
.
875 lb/ft 3
gi3
Using Equation 1-2, the density of the gas as it enters this drill string section, gi3 ,
is
875
.
gi3
.
32 2
lb sec 2
0 272
.
gi3 4
ft
From Equation 9-7, the kinematic viscosity of the gas at this location, , is
gi3
.
0 000000251
gi3
0 272
.
ft 2
.
0 000000922
gi3
sec
The average kinematic viscosity of the mixture as it enters this drill string section,
, is
avi3
.
.
.
( 1 821)( 0 000000922) ( 14 60)( 0 00001078)
.
avi3
.
.
1 821 14 60
2
.
0 00000969 ft /sec
avi3