Page 506 - Air and Gas Drilling Manual

.
0 375 ft
D
2
The total length of the lumped drill pipe tool joints increment (fourth), H 4, in
the openhole section of the annulus is Chapter 10: Stable Foam drilling 10-31
,
2 500
H 4 15 .
30
H 4 125 ft
The inside diameter of the openhole along this length of this openhole section of
the annulus is
D h 0 656 ft
.
and the outside diameter of the drill pipe tool joints along this length is

D 0 552 ft
.
3
The total length of the drill collar increment (fifth), H 5, in the openhole section
of the annulus is
H 5 500 ft

The inside diameter of the openhole along this length of the openhole section of the
annulus is

.
D h 0 656 ft
and the outside diameter of the drill collars along this length is
d 675 inches
.
4
d 4
D 4
12
.
D 0 563 ft
4
Using the description of the annulus geometry given above each of the five
increment changes in cross-sectional area can be analyzed starting with the stable
foam flow exiting at the top of the annulus.