Guidelines & Recommended Practices
Selection of Artificial Lift Systems
for Deliquifying Gas Wells
Prepared by Artificial Lift R&D Council
4.1 Know and practice pertinent guidelines and recommended
practices for installation, operation, and maintenance of each
form of artificial lift
This presents proven guidelines and recommended practices for installation,
operation, and maintenance of each type of artificial lift.
1. Sucker rod pumping
2. Plunger Lift
3. Progressing cavity pumping
4. Electrical submersible pumping
5. Hydraulic pumping
6. Soap sticks
7. Batch chemical treatment
8. Continuous chemical injection
9. Velocity strings
10. Surface compression
11. Continuous gas-lift
12. Intermittent gas-lift
13. Vortex
14. Injection
1. Beam and Pumping Systems:
If at all possible set the pump below the perforations enough so that there will be sufficient
pressure for NPSH even if all fluids are below the perforations. See below:
Selection of Artificial Lift Systems for Deliquifying Gas Wells
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For beam and PCP systems the pump intake only needs to be a joint or so below the perforations to satisfy NPSH requirements. For a jet system, the distance is impractical if fluids are to be taken off the perforations or nearly so.
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If a pumping system cannot be installed with the pump below the perforations, then there
are many problems to contend with considering gas separation and it could be that gaslift could be better situation.
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For a beam pump system if the unit is set fairly shallow (1000, 2000, or 3000 ft) and the
pump size is small (near one inch or somewhat larger) then a tubing anchor may not be
needed.
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A pump-off control (POC) unit, small rods, and a small pump diameter are all possibilities
and desired when moving small amounts of fluids with a beam pump system.
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As explained elsewhere it is good with small casing (4 ½ and 5 ½) to have a POC that
will shut in the casing for a short time before pumping begins and to open the casing near
the end of the pump cycle to take care of fact that gas production could blow up the fluids
up the casing and starve the pump of fluids.
Selection of Artificial Lift Systems for Deliquifying Gas Wells
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2. Plunger Lift:
Where to place the tubing?
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Ideal tubing placement will result in the well being unloaded to the lowest possible perforation depth without putting the well in danger of excessive loading.
Generally this will occur when the most prolific production zone is completely uncovered
(tubing is at the bottom of this zone).
Using reservoir knowledge the customer must distinguish which zone will be the best performer and place the tubing to that depth to avoid that zone having additional back pressure on it from liquid level.
If the above information is unavailable, experience has taught that being as deep as possible is best and in order to get the plunger system to run.
It may require optimization in the form of tubing movement when different zones are most
active.
Ultimately the plunger should be run as low as possible while still maintaining a GLR that
will allow the plunger to work.
Downhole Equipment for Plungers
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Bumper springs.
Seating cups, collar stop, tubing stop.
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With or without standing valve.
Only a tubing stop!
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Some installations employ a travelling bumper spring to keep accumulations off spring
Wellhead ID:
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Insure the path in the wellhead is sleeved such that it is close to the tubing ID to prevent
plunger damage and hang ups.
Packer:
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For a “conventional” plunger best operation is achieved with no packer.
Mechanical Considerations That May Lead to Problems with
Plungers
(From Phillips and Listiak, SWPSC)
Well
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Sand
Scale, Asphaltenes
Temperature
Tubing
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Continuous I.D. (packers, anchors, crimps, scale, soap build up)
Packer in place or Tubingless Completion
Selection of Artificial Lift Systems for Deliquifying Gas Wells
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Hole in tubing.
Bottom of tubing
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Do not place below perforations.
Place just below best gas producing zone in a long pay inrterval.
Wellhead
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Continuous I.D. (Valves, tees, landing threads, hanger)
Minimize unnecessary valves/tees
Piping must be "plumb“
Use double outlet wellhead or lubricator
Flanged may be preferable to threaded joints (safety)
Surface Equipment
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Tank and separator capacities
Bottle necks, chokes, bends, tees, elbows, small tubing
Flowline limitations-- pressure increases when plunger on
Orifice plate sizing
Unable to monitor sales pressure
Compression
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Centralized or single wellhead compression
Suction pressure control
Well “fights”-- correct compressor size, synchronization
High line pressure delays
By-pass valving
Plunger Maintenance:
(From Phillips and Listiak, SWPSC)
Plungers
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Pad Type
- Check for Looseness and Wear
Brush Type
- Gauge O.D. with Gauge Ring Or Caliper (Temperature limits)
Bar Stock (use only as last resort)
- Gauge with Calipers
Two Piece
- Check Ball for indentations, sleeve for wear
Lubricator Shock Spring
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Visual Inspection and Looseness in Catcher
O-Rings
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Visual Inspection, Leaks
Controller
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Fuse Link, Ground
Module
Battery
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Selection of Artificial Lift Systems for Deliquifying Gas Wells
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Latch Valve
Sensor / MSO (Magnetic Shut Off)
Filter Element
Automated catcher if present
Track Plunger Operations
(From Phillips and Listiak, SWPSC)
Keep a History
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Cycles / Trends
- Optimize Production and Minimize Operator Time
Plunger Changes
- Get most efficient use and life from plunger
- Optimize Profit
Surface Shock Spring
- Optimize Plunger Life
- Reduce Cost (Spring Costs Much Less Than Plunger)
How to Track
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Controller Cycle Forms
Plunger System Tracking Forms
Plunger well data linked directly to a database
Record # cycles or mileage such as 10,000-15,000 miles?
Failure Analysis
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Determine the life span of plungers/shock springs
Reasons for frequent plunger changes
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Selection of Artificial Lift Systems for Deliquifying Gas Wells
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Example Plunger Tracking Form
3. Progressing Cavity Pump (PCP):
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On installation, land on tagbar and pull up the tagbar distance plus calculated rod stretch
under load.
Use anchor catcher or no-turn tool at the pump.
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Install rod guides where needed from calculations or indications of wear.
Use torque limiting device at surface.
Selection of Artificial Lift Systems for Deliquifying Gas Wells
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Avoid pumping off.
Guard all rotating components at surface.
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For gas production, set the punp intake below perforations.
Set tightness of fit in shop so that after equilibrating in field operations the pump performance is 70-80% of no slip performance based on pump constant and measured rotational speed.
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Don’t exceed the max pressure or head across a particular pump.
4. Electrical Submersible Pump (ESP):
For gas handling, the ESP should be set below the perforations but this is problem for ESP’s.
Methods for handling setting below perforations include:
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Use a re-circulating pump
Use a shroud (if clearances permit)
Use high temperature motor trim (possibly with high temp motor cut-out
Recirculating pump for setting ESP below Perforation: (From Baker Hughes)
Selection of Artificial Lift Systems for Deliquifying Gas Wells
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Shrouded Unit to Set ESP below Perforations (if clearances allow)
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Selection of Artificial Lift Systems for Deliquifying Gas Wells
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Consider Inverted Shroud for gas handling if ESP must be above perforations (Baker
Hughes)
5. Hydraulic pumping
6. Soap sticks
7. Batch chemical treatment
8. Continuous chemical injection
9. Velocity strings
10. Surface compression
Selection of Artificial Lift Systems for Deliquifying Gas Wells
11. Continuous gas-lift
12. Intermittent gas-lift
13. Vortex
14. Injection
Page 10