Page 178 - Petroleum Production Engineering, A Computer-Assisted Approach

Guo, Boyun / Computer Assited Petroleum Production Engg 0750682701_chap12 Final Proof page 174 4.1.2007 2:43pm Compositor Name: SJoearun

12/174 ARTIFICIAL LIFT METHODS
to be used. Select surface and subsurface equipment for the Therefore, the selected pumping unit and rod meet well
installation. Use a safety factor of 1.35 for the prime load and volume requirements.
mover power.
7. If a LUFKIN Industries C–320D–213–86 unit is
chosen, the structure unbalance is 450 lb and 4 No. 5
Solution ARO counterweights placed at the maximum position
(c in this case) on the crank will produce an effective
1. Assuming volumetric efficiency of 0.8, the required
counterbalance load of 12,630 lb, that is,
pump displacement is
(37) (96:05)
(600)=(0:8) ¼ 750 bbl=day: W c þ 450 ¼ 12,630 lb,
(37) (111)
2. Based on well depth 3,500 ft and pump displacement which gives W c ¼ 14,075 lb. To generate the ideal counter-
750 bbl/day, Fig. 12.8 suggests API pump size 320 unit balance load of C ¼ 10,327 lb, the counterweights should
with 84 in. stroke, that is, a pump is selected with the be placed on the crank at
following designation:
(10,327)(111)
r ¼ (37) ¼ 31:4in:
C---320D---213---86 (14,076)(96:05)
3. Table 12.4 g suggests the following:
8. The LUFKIN Industries C–320D–213–86 unit has a
Tubing size: 3 in. OD, 2.992 in. ID gear ratio of 30.12 and unit sheave sizes of 24, 30, and
1
Plunger size: 2 ⁄ 2 in. 44 in. are available. If a 24-in. unit sheave and a 750-
7
Rod size: ⁄ 8 in. rpm electric motor are chosen, the diameter of the
Pumping speed: 18 spm motor sheave is
4. Table 12.1 gives d 1 ¼ 96:05 in., d 2 ¼ 111 in., c ¼ 37 in., (18)(30:12)(24)
and h ¼ 114 in., thus c/h ¼ 0.3246. The spreadsheet d e ¼ ¼ 17:3in:
program SuckerRodPumpingFlowRate&Power.xls gives (750)
q o ¼ 687 bbl=day > 600 bbl/day
P pm ¼ 30:2hp 12.7 Principles of Pump Performance Analysis
5. The spreadsheet program SuckerRodPumpingLoad.xls The efficiency of sucker rod pumping units is usually ana-
gives lyzed using the information from pump dynagraph and
polisher rod dynamometer cards. Figure 12.9 shows a sche-
PRL max ¼ 16,121 lb matic of a pump dynagraph. This instrument is installed
PRL min ¼ 4,533 lb immediately above the plunger to record the plunger stroke
T ¼ 247,755 lb < 320,000 in.-lb and the loads carried by the plunger during the pump cycle.
C ¼ 10,327 lb The relative motion between the cover tube (which is
2
7
6. The cross-sectional area of the ⁄ 8 -in. rod is 0.60 in. . attached to the pump barrel and hence anchored to the
tubing) and the calibrated rod (which is an integral part of
Thus, the maximum possible stress in the sucker rod is
the sucker rod string) is recorded as a horizontal line on
the recording tube. This is achieved by having the record-
s max ¼ (16,121)=(0:60) ¼ 26,809 psi < 30,000 psi:
ing tube mounted on a winged nut threaded onto the
calibrated rod and prevented from rotating by means of
2,500
Curve API size Stroke
40
Pump Displacement (bbl/day) 1,500 G 320 144
34
A
2,000
B
42
57
80
48
C
114
54
D
160
64
E
F
74
228
1,000
84
H
640
500
0
0 2,000 4,000 6,000 8,000 10,000 12,000
Pump Setting Depth (ft)
Figure 12.8 Sucker rod pumping unit selection chart (Kelley and Willis, 1954).