STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

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Downhole Motors 889
- 9*P,a%
HP,, - -
1,714 ' (4-1 67)
It should be noted that the positive displacement motor performance parameters
are independent of the drilling mud weight. Thus, these performance
parameters will vary with motor design values and the circulation flowrate.
If the above performance parameters for a positive displacement motor design
are known for a given circulation flowrate (denoted as l), the performance
parameters for the new circulation flowrate (denoted as 2) can be found by the
following relationships:
Torque
M, = MI
(4-1 68)
Speed
N2 = ( $)Nl
(4-169)
Power
k 1
HP, = 2 HP,
(4-170)
Table 4-1 14 gives the performance characteristics for various circulation
flowrates for the 1:2 lobe profile, 6 $-in. outside diameter positive displacement
motor. Figure 4-204 shows the performance of the 1:2 lobe profile positive
displacement motor at a circulation flowrate of 400 gal/min.
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Circulation
Rate
(gpm)
200
250
300
350
400
450
500
Table 4-114
Positive Displacement Motor, 6?4-in, Outside Diameter,
1:2 Lobe Profile, Five Motor Chambers
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speed
(rpm)
Courtesy Eastman-Christensen
Maximum
Differential
Pressure (psi)
205 580
255 580
306 580
357 580
408 580
460 580
510 580
Maximum
Torque
(ft-lbs)
1500
1500
1500
1500
1500
1500
1500
Maximum
Horsepower
59
73
87
102
116
131
145