Page 549 - Air and Gas Drilling Manual

10-74 Air and Gas Drilling Manual
depth of 7,000 ft. The minimum injection pressure is approximately 229 psia and
occurs at the end of the interval at a depth of 10,000 ft.

Figure 10-3: Pressure profile in the inside of the drill string and in the annulus for
Illustrative Example 10.2 (q g = 1,658 acfm and a drilling depth of 10,000 ft).
Figure 10-5 shows the water (and surfactant) injection volumetric flow rates as a
function of drilling time for the interval from 7,000 ft to 10,000 ft. The maximun
volumetric flow rate of water (105 gal/min) occurs while drilling at a depth of
10,000 ft. The minimum volumetric flow rate of water (78 gal/min) occurs while
drilling at a depth of 7,000 ft.
Figure 10-6 shows the air injection volumetric flow rates as a function of
drilling time for the interval from 7,000 ft to 10,000 ft. The maximun volumetric
flow rate of air (1,658 acfm) occurs while drilling at a depth of 10,000 ft. The
minimum volumetric flow rate of air (1,240 acfm) occurs while drilling at a depth of
7,000 ft.