Page 152 - Air and Gas Drilling Manual

4-38 Air and Gas Drilling Manual
Figure 4-22 shows a skid mounted primary compressor system unit which has a
Gardner Denver Model WEN, two-stage, reciprocating piston compressor. The
Gardner Denver Model WEN is operated at 1,000 rpm. At this speed, the
compressor has a volumetric flow rate of 700 scfm and a maximum pressure
capability of 350 psig (at API Mechanical Equipment Standards standard
conditions). The compressor and its cooling subsystem is shown at the right end of
the skid in Figure 4-22. On the left end of the skid in Figure 4-22 is the Caterpillar
Model D353 prime mover. The Caterpillar Model D353 is an in-line six cylinder,
diesel fueled prime mover. This prime mover is turbocharged and aftercooled and is
rated to produce a peak of 270 horsepower at a speed of 1,000 rpm (at API
Mechanical Equipment Standards standard conditions).

Figure 4-22: Skid mounted reciprocating piston primary compressor system unit
(courtesy of Mountain Air Drilling Service)
Figure 4-23 shows a skid mounted booster compressor system unit which has a
Gardner Denver Model MDY, two-stage, reciprocating piston compressor. The
compressor is seen at the front end (right end) of the skid in Figure 4-23. The
compressor is driven by a Caterpillar Model D353 prime mover. This is the same
prime mover that is used for the primary compressor system unit discussed above.
The prime mover is rated to produce a peak 270 horsepower at a speed of 1,000 rpm
(at API Mechanical Equipment Standards standard conditions). However, unlike the
primary compressor system discussed above, the booster compressor system may be
operated at speeds different from the 1,000 rpm. The prime mover would produce an
approximate peak of 230 horsepower at 900 rpm, and a peak of 300 horsepower at
1,100 rpm.
This booster compressor system unit is usually operated in series with the
primary compressor system. When the drilling rig requires compressed air at
pressures above the 350 psig maximum capability of the primary, the air flow from
the primary is conducted to the inlet of the booster. In this series configuration, the
booster is engaged and the volumetric flow rate from the primary is further
compressed to pressures above 350 psig level. However, the booster can also be
used to compress pipeline natural gas to pressures above typical pipeline pressures
for use on a drilling rig.