Page 14 - Air and Gas Drilling Manual

xv List of Symbols
2
P Tee
= flow work, ft-lb/lb
Pv
= volumetric flow rate of the gas above the drill bit inside the drill pipe,
Q ai = pressure upstream of the Tee at the top of the annulus, lb/ft abs
3
ft /sec
Q bh = volumetric flow rate of the gas at the bottom of the borehole in the
3
annulus, ft /sec
q f = total volume of fuel consumption rate, gal/hr
q fw = approximate volumetric flow rate of formation water, gal/hr (bbl/hr)
3
Q g = gas volumetric flow rate, ft /sec
Q ga = volumetric flow rate of gas exiting the cased annulus and starts into the
3
Tee, ft /sec
Q gbh = volumetric flow rate of the gas at the bottomhole pressure and temperature
3
conditions, ft /sec
3
q i = input volumetric flow rate, ft /min
3
Q i = volumetric flow rate entering the first stage of the compressor, ft /sec
3
(m /sec)
q iw = flow rate of injected water, gal/hr
3
Q m = volumetric flow rate of drilling mud, ft /sec
3
Q mav = average volumetric flow rate of air through the motor cavity, ft /sec
q mav = average volumetric flow rate of air through the motor cavity, gal/min
q s = volumetric flow rate, cfm
3
Q w = volumetric flow rate of water, ft /sec
q w = volumetric flow rate of water, gal/min
R = gas constant for API standard dry air, 53.36 ft-lb/lb-°R

R a = gas constant for API standard dry air, 53.36 ft-lb/lb-°R
r c = total fixed compression ratio across two stage compressor
r s = compression ratios for each stage
r sb = first stage compressor ratio
r sp = fixed compression ratio for single-stage primary