Page 240 - Air and gas Drilling Field Guide 3rd Edition

9.4 Nonfriction and Friction Illustrative Examples 231

Appendix B). Therefore, the absolute temperature of the rock formations at the sur-
face is

t r ¼ 44:74 F
T r ¼ t r þ 459:67

T r ¼ 504:41 R:
The depth of the well is
H ¼ 10000 ft:
The bottom hole temperature, T bh ,is
T bh ¼ T r þ 0:01 H

T bh ¼ 604:41 R:
The borehole average temperature is
504:41 þ 604:41
T av ¼
2

T av ¼ 554:41 R:
The open hole diameter is
d h ¼ 7:875 inches
d h
D h ¼
12
D h ¼ 0:656 ft:
The estimated drilling rate of penetration is 60 ft/hr. The weight rate of flow of
solids from the advance of the drill bit is

p 2 k
_ w s ¼ D ð 62:4Þ S s (9-8)
h
4 ð 60Þ 60Þ
ð

60
2
p
_ w s ¼ ð 0:656Þ ð 62:4Þ 2:7Þ
ð
4 ð 60Þ 60Þ
ð
_ w s ¼ 0:949 lb=sec:
The volumetric flow rate of drilling mud in consistent units is
ð
ð 191Þ 231Þ
Q f ¼ 3
ð 12Þ 60ð Þ
3
Q f ¼ 0:426 ft =sec:
The weight rate of flow of the drilling mud is
_ w f ¼ 75:0ð Þ 0:426Þ
ð
_ w f ¼ 31:92 lb=sec: