Page 533 - Air and Gas Drilling Manual

10-58 Air and Gas Drilling Manual
The total length of the lumped drill pipe tool joints geometry increment, H 2, in
the cased section is
H 2 350 ft
The inside diameter of the drill pipe tool joints lumped geometry in this cased
section is
D 0 292 ft
.
6
The total length of the lumped drill pipe body geometry increment, H 1, in the
cased section is
,
H 1 6 650 ft
The inside diameter of the drill pipe body lumped geometry in this cased section is
.
D 7 0 319 ft
Inside the Drill String (10,000 ft to 7,000 ft)
The fifth drill string section increment is denoted by the length H 5. The
temperature at the bottom of the drill collars (bottomhole temperature) in the
openhole section is
T 5 604 41˚R
.
The average temperature of the drill collar length H 5 and, thus, the temperature of the
aerated fluid flow inside the drill collars is

T 601 91˚R
.
av5
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 collars along H 5. This is accomplished by determining
the Reynolds number at the entrance end of the inside of the drill collar section and
assuming this Reynolds number approximates the flow conditions throughout the
inside of the drill collar section.
The absolute viscosity of the gas (air) at atmospheric conditions, , is
g
.
0 012 cps
g
0
0
0
(.012 ) (.001 ) (.02089 )
g