Page 370 - Air and Gas Drilling Manual

Chapter 8: Air, Gas, and Unstable Foam Drilling 8-53
large prime mover (see Figure 4-24). This compressor unit has a MAN Model
GHH-CF246G, single-stage, rotary screw primary compressor and an Ariel Model
JGJ/2, two-stage, reciprocating piston booster compressor (see Figure 4-24 in
Chapter 4). These two compressors are driven by a single Caterpillar Model 3412
prime mover. The rotary primary compressor has an API rated volumetric flow rate
of 1,698 scfm (adjusted from ASME standard atmospheric conditions, see
Illustrative Example 3.3a, and Chapter 4). The rotary primary compressor also has a
fixed pressure output of 190 psig (at ASME standard atmospheric conditions, see
Chapter 4). The Caterpillar Model 3412 prime mover is API rated at 740
horsepower at 1,800 rpm (the operating speed for the system).

Figure 8-9: Fuel consumption rate as a function of drilling time for the reciprocating
piston compressor of Illustrative Example 8.3c.

In the compressor selection process of Illustrative Example 8.3a it was found
that this candidate compressor system would require the volumetric flow rate output
of two units (or 3,396 acfm) to drill the example borehole. Using this new