Page 487 - Air and Gas Drilling Manual

10-12 Air and Gas Drilling Manual
459 67
.
t
T
r
r
T
.
504 41˚R
r
The depth of the well, H, is
,
H 10 000 ft
The bottomhole temperature, T bh, is
.
T bh T r 001 H
T bh 604 41˚R
.
The borehole average temperature, T av, is
T sr T bh
T av
2
504 41 604 41
.
.
T av
2
.
T 554 41˚R
av
A simplified borehole geometry is assumed for the non-friction solution. The
borehole is assumed to be a uniform diameter represented by the openhole diameter
(the drill bit diameter). The openhole diameter, D h, is
d h 7 875 inches
.
d h
D
h
12
D h 0 656 ft
.
The drill string outside diameter is assumed to be a uniform diameter represented by
the outside diameter of the drill pipe. The drill pipe outside diameter, D p, is
d p 450 inches
.
d p
D p
12