Downhole Pump
The Five Basic Components of a Sucker Rod Pump:
Barrel Tubes:
Plunger:
Rings for Soft Packed Plungers:
Traveling Valves:
Standing Valves:
Valves for Traveling and Standing:
Seating Assemblies:
Operations of a Downhole Pump
- A sucker rod pump is no more than a cylinder, or tube, consisting of two sections or chambers.
- One section is stationary or secured to the tubing.
- The other section travels with the sucker rod string.
- There is usually two valves working with these sections taking turns opening and closing.
- The valves transfer fluid from the bottom chamber to the top chamber and ultimately into the tubing and up to the wellhead.
Arrows Show Fluid Travel
on the Upstroke |
Arrows Show Fluid Travel
on the Downstroke |
Types of Sucker rod Pumps
- Insert Type Pumps
- Tubing Pumps
- Specialty Pumps
Insert Type Pumps
- Installed on the end of a sucker rod string as a complete unit.
- Can be randeeper than Tubing Pump.
- Special service application are available for most types.
- Less service cost than a tubing pump.
Types of Insert Pumps
Bottom Hold down:
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Bottom Hold down:
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Mechanical Type Holddowns also available in same configuration
All pumps shown with Cup Type Holddowns
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RWTC-API Insert Pump
- Barrel Travel with Rod String.
- Bottom Holddown.
- Thin Wall Varrel.
Advantages of RWTC Pumps
- Recommended for sandy wells.
- More rugged than a stationary barrel with respect to the sucker rod connection: Pull Tube vs Valve Rod
- Recommended for intermittent pumping wells.
Disadvantages of RWTC Pumps:
- Not recommended for gassy wells.
- Not recommended for wells with low fluid levels.
- Not recommended for deep wells.
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RWAC-API Insert Pump
- Plunger Travels with Rod String.
- Top Holddown.
- Thin Wall Barrel.
- Barrel Extends Below Seating Nipple.
Advantages of RWAC Pumps
- Recommended for sandy wells.
- Recommended for low fluid levels, gassy, or foamy wells.
- Recommended for wells requiring long pumps.
Disadvantages of RWAC Pumps:
- Not recommended for deep wells.
- Valve rod is the weak link.
- Not recommended for intermittent pumping.
- Tubing erosion opposite top guide.
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RHBC-API Insert Pump
- Plunger Travels with Rod String.
- Bottom Holddown.
- Heavy Wall Barrel.
Advantages of RHBC Pumps
- Recommended for deep wells.
- Recommended for low fluid levels.
- Recommended for stroke through design to combat scale and/or gyp.
Disadvantages of RHBC Pumps:
- Not recommended for sandy wells.
- Valve rod is the weak link.
- Not recommended for intermittent pumping in sandy wells.
- Barrel subject to corrosive attack.
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RHAC-API Insert Pump
- Plunger Travels with Rod String.
- Top Holddown.
- Heavy Wall Barrel.
- Barrel Extends Below Seating Nipple.
Advantages of RHAC Pumps
- Recommended for sandy wells.
- Recommended for low fluid levels, gassy, or foamy wells.
- Recommended for stroke through design to combat scale and/or gyp.
- Recommended for wells requiring long pumps.
Disadvantages of RHAC Pumps:
- Not recommended for deep wells.
- Valve rod is the weak link.
- Not recommended for intermittent pumping.
- Tubing erosion opposite top guide.
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Tubing Pumps
- Typically produces more fluid than a rod pump.
- More costly to service than a rod pump.
- Application is in shallow to medium depth wells due to loading on rod string and pumping unit.
- Not a good choice in gassy wells.
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THC-API Tubing Pump
- Plunger Travels with Rod String.
- Barrel Ran on Bottom of Tubing String.
- Plunger Ran on Bottom of Rod String.
- Bottom Holddown.
- Heavy Wall Barrel.
Specialty Pumps
- Typically More Costly, but More Cost Efficient
- Application from shallow, medium to deep
- Typically Non-API Configuration
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Hollow Tube
- Plunger Travels with Rod String.
- Bottom Hold Down.
- Available in Thin & Heavy Wall.
- Available in Bottom & Top Hold Down.
- Valve Rod is Replaced with Pull Tube.
- Valve can be added on top of tube.
Advantages of Hollow Tube Pumps:
- Recommended for deep wells.
- Pump discharge is spread across pump stroke (helps reduce tubing erosion).
- Two Stage effect with valve on top of tube.
- Pull Tube is more rigid than typical valve rod
Disadvantages of Hollow Tube Pumps:
- Not recommended for sandy wells.
- Barrel subject to corrosive attack.
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LPSB-(Long Plunger Short Barrel)
- Can be built as Stationary, Travel or Tubing Barrel type pump.
- Bottong Hold Down.
- Heavy Wall Barrel construction.
- Valve Rod is Replaced with Plunger.
- Check Valve on top of pump.
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THOS-Oversize Tubing Pump
- Barrel Ran on Bottom of Tubing String
- Plunger Runs on Bottom of Rod String
- Heavy Wall Barrel-Strong Construction
- On-Off Tool
Advantages of THOS Pumps:
- Large Capacity
- Bore Size greater than ID of Tubing String
- Large Flow Area good for producing heavy viscous fluid
- Not Limited by Temperature
- Better at producing gas than an API Tubing Pump
- Heavy Construction
- Polished Rod used as Valve Rod
Disadvantages of THOS Pumps:
- Pull Tubing to replace entire pump
- Connection of sucker rods to pump after pump has been installed
- Not recommended for deep wells
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Accessories Available for Subsurface Pumps
Steam-Bypass Pumps
- Production of heavy, viscous oil presents tremendous challenges for oil producers. Thermal recovery, or steam injection, is one of the most accepted aids in heavy-oil production. In conjunction with standard API insert-rod pumps, the steam-bypass system provides a method of injecting steam into the producing formation without removing the subsurface pump from the well.
- Traditional methods require either completely removing the pump or lifting the pump clear of its seating area to allow adequate annular area for steam passage. Injecting steam without adequate area can result in increased steam pressure, diminished flow rates, and unnecessary steam stresses on the subsurface pump parts. To help overcome this problem, the steam-bypass system consists of two devices joined together as a unit.
- The holddown section uses corrosion-resistant, stainless steel, friction rings to provide a positive holding force. Rigid machine tolerances during manufacture ensure minimum clearances between the friction rings and the seating nipple, effectively preventing fluid passage.
- The bypass is a specially sized, reduced-diameter tube, fitted between the API pump and the seal section. This design increases the area available for steam when the bypass is positioned in the seating nipple.
- API threads, tolerances and sizes of the steam-bypass system allow it to be used with standard API insert pumps sized for 2 3/8-, 2 7/8- or 3 1/2-in. tubing. Pumps can be provided in either RW or RH with pump metallurgy designed to meet the well environment.
Operation
- Like other API insert pumps, the steam-bypass pump is positioned on the rod string during installation. When the pump reaches the seating nipple, rod weight is transferred to the pump, which forces the friction rings into the recessed area of the special seating nipple. In spacing the well, an additional length of polish rod—equal to the length of the bypass tube—is required. The additional length of polish rod is positioned below the stuffing box at the highest point of the pumping unit stroke. Startup is then accomplished in the same way as other API insert pumps.
Steaming
- Changing from a pumping well to steam injection requires that the polish rod be lifted until the subsurface plunger meets the top of the pump. The polish rod is clamped off at the stuffing box, and the pumping unit can be used to lift the polish rod an additional 36 in. (91 cm), positioning the bypass section in the bore of the seating nipple. The well is then injected with steam or hot oil, filling the inside of the pump plunger as well as the annular area between the tubing and the pump and avoiding unnecessary damage to the pump barrel as a result of steam stress. After the steam cycle is completed, the pump is lowered to and seated in the seating nipple by applying rod weight to the pump, at which time production can resume.
- The high-temperature bypass system can be successfully operated at temperatures of 150° to 1,000°F (66° to 538°C).
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Steam-Bypass Pumps
- API-type RWA steam-bypass, heavy-oil pumps
- Friction ring, top holddown
- Tubing × Pump Bore Size (in.) 20 × 150, 25 × 200, 30 × 200 & 30 × 250
Traveling Assembly
- A - Guide, spiral, no coating
- B - Bushing, valve-rod
- C - Rod, valve
- D - Coupling
- E - Plunger, pin-end, spray-metal
- F - Cage, closed-plunger
- G - Valve, ball-and-seat
- H - Plug, seat
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Stationary Assembly
- J - Guide, valve-rod, sand-check
- K - Drop, sand-check
- L - Seat, sand-check
- M - Mandrel, friction ring
- N - Spacer
- P - Friction ring, stainless steel
- Q - Locknut
- R - Bushing
- S - Coupling, extension, bypass
- T - Connector
- U - Barrel, RW, CID steel
- V - Cage, closed-barrel
- W -Valve, ball-and-seat
- X - Bushing
- Y - Nipple, seating
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