Page 270 -

234 Appendices

4500
Minimum Required Air Injection Rate (scfm) 3000 Q =4 bbl/hour
4000
3500

2500
w
2000
Q =8 bbl/hour
w
1500
Q =12 bbl/hour
w
Q =16 bbl/hour
w
1000
Q =20 bbl/hour
w
Q =24 bbl/hour
500
w
For cuttings removal
0
0 2000 4000 6000 8000 10000 12000 14000 16000
Depth (ft)
Figure B.1 Calculated air injection requirements for drilling a 7⅞-in hole with a 4½-in
drill pipe at an ROP of 60 ft/hr (water-air interfacial tension = 60 dynes/cm).
5000
Minimum Required Air Injection Rate (scfm) 3500 Q =4 bbl/hour
4500
4000

3000
2500
w
2000
Q =8 bbl/hour
w
Q =12 bbl/hour
1500
w
Q =16 bbl/hour
w
1000
w
Q =24 bbl/hour
500
w
For cuttings removal
0 Q =20 bbl/hour
0 2000 4000 6000 8000 10000 12000 14000 16000
Depth (ft)
Figure B.2 Calculated air injection requirements for drilling a 7⅞-in hole with a 4½-in
drill pipe at an ROP of 120 ft/hr (water-air interfacial tension = 60 dynes/cm).