Reciprocating Rod Lift
Ro R ota taff lex Long Long-St Stro roke ke Pumping Pumping Unit Unit ®
The Rotafex unit unit is Weatherford’s long-stroke pumping unit for sucker-rod pumps. Using proven technology and design innovations, the unit provides greater efciency and cost effectiveness for pumping deep, troublesome, and high-volume wells; and with the Rotafex unit, unit, sucker-rod pumps can be used for applications where electric submersible or hydraulic subsurface pumps were once required. Long pump stroke (up to 366 in., or 9.3 m) and virtually no minimum speed provide more complete pump llage and lower dynamic loading. Dynamometer cards run on Rotafex applications applications are similar to a theoretically perfect card. Pumping with the Rotafex unit unit reduces stress on equipment because the rod string is operated at relatively constant velocities. Constant velocity and fewer strokes per barrel increase the life span of the pumping unit, downhole pump, and rod string. Servicing a well with the Rotafex unit unit is safe and simple. After the bridle and carrier bar are disconnected from the polished rod, the Rotafex unit rolls away from the wellhead without any disassembly.. After a workover is completed, the disassembly unit is rolled back into place, and the carrier bar is reconnected to the polished rod.
Applicati Appli cations ons • High-volume and high-load wells • Deviated and horizontal wells • Wells that experience frequent downhole equipment failures
• Operations requiring energy savings
Weatherford International Ltd.
515 Post Oak Blvd., Suite 600 Houston, Texas 77027 USA Tel: 713-693-4000 www.weatherford.com
© 2007 Weatherford. All rights reserved.
843.02
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Reciprocating Rod Lift
Rot R otaf aflex lex Long-Stroke Pumping Unit ®
Features, Advantages Advantages and Benefts • Extended stroke length and unique design make the Rotafex unit signicantly more efcient than other pumping units. Savings in energy costs typically range from 15 to 25 percent.
• Constant velocity and fewer strokes per barrel increase the life span of the pumping unit, downhole pump, and rod string.
• Extended stroke length allows for fewer cycles and reversals, resulting in increased system efciency and reliability reliability..
• Long pump stroke and virtually no minimum speed provide more complete pump llage and lower dynamic loading.
• The Rotafex unit unit is shipped in one piece for ease of service and installation.
• Longer downhole stroke provides better pump compression ratio to help eliminate gas-lock problems.
• The unique mechanical reversing mechanism is proven in the eld for over 20 years.
• Long-life, heavy-duty load belt, used to link the power train to the rod string, acts as a shock absorber, effectively effectively reducing stress on the entire system.
• The short radius of the torque arm markedly reduces required torque demand and allows the use of a smaller prime mover and gear reducer, which are less expensive to buy and operate.
Downstroke Position
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Reciprocating Rod Lift
Rot R otaf afle lex x Long-Stroke Pumping Unit ®
Specifca Spec ifcation tionss Model
Reducer torque (in.-lbf,
900
Maximum polished rod weight (lb/kg (lb/ kg ) Maximum speed* (spm)
288 7.3
Auxiliary counterweight counterweight (lb/kg (lb/kg ) Total weight (lb/kg (lb/ kg )
1151
420,000 47.45
306 7.8
366 9.3
36,000 16,329 4.50
Minimum speed (spm) Weight of counterweight assembly (lb/kg (lb/ kg )
1150
320,000 36.16
kN•m)
Stroke length (in./ m)
1100
50,000 22,680 4.30
3.64
3.75
No absolute minimum 9,400 4,264
9,800 4,445
21,980 9,969
30,200 13,698
31,380 14,234
40,000 18,144
Unit dimensions, L × W × H, (ft/ m)
21.8 × 7.8 × 40.5 6.64 × 2.38 × 12.34
23.8 × 8.5 × 44.5 7.25 × 2.59 × 13.56
23.8 × 8.5 × 49.5 7.25 × 2.59 × 15.09
23.8 × 8.5 × 49.5 7.25 × 2.59 × 15.09
Unit shipping size, L × W × H, (ft/ m)
40.5 × 7.8 × 9.0 12.34 × 2.38 × 2.74
44.5 × 8.5 × 10.5 13.56 × 2.59 × 3.20
49.5 × 8.5 × 10.5 15.09 × 2.59 × 3.20
49.5 × 8.5 × 10.5 15.09 × 2.59 × 3.20
42,900 19,459
52,300 23,723
53,880 24,440
55,000 24,948
466.0 × 50.0 11.84 × 1.27
466.0 × 50.0 11.84 × 1.27
Unit shipping weight (lb/kg (lb/kg )
24.0 × 8.5 7.32 × 2.62
Base dimensions, L × W (ft/ m)
29,000 13,154
Base weight (lb/kg (lb/ kg )
–40° to +140° –40° to +60°
Working temperature (°F/°C (°F/ °C ) Load belt dimensions, L × W (in./ m) Load belt tensile strength, PIW (lb/ kg ) Automatic brake brake system
390.0 × 42.0 9.91 × 1.07
406.0 × 50.0 10.3 × 1.27 10,000 4,536 Yes
*Higher speeds are attainable with variable frequency drive, increasing production by as much as 25%.
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Reciprocating Rod Lift
Rot R otaf aflex lex Long-Stroke Pumping Unit ®
Options • Weatherford’ Weatherford’s s hydraulically powered Rotafex rollback rollback system for moving and repositioning the Rotafex long-stroke pumping unit is available for new installations of Rotafex long-stroke long-stroke pumping units and can also be retrotted to previously installed pumping units.
• Gas-engine extensions. • Wire-mesh safety fences. • Variable frequency drive.
