1. How to Maintain High Producing Efficiency in Sucker Rod Lift Operations
Lynn Rowlan

2. What is High Efficiency?
Electrical Efficiency
Total System Efficiency Should be greater than 50%
Surface Efficiency should be greater than 80%
Mechanical Efficiency
Pump, Rods, Pumping Unit Size and Balance
Reservoir Producing Rate Efficiency
Should be greater than 95%

3. High Efficiency?
High electrical efficiency, mechanical efficiency and reservoir producing rate efficiency requires:
Measurement of motor power, dynamometer data, the liquid level depth with casing pressure and a representative well test.
(Electrical efficiency, mechanical efficiency and reservoir producing rate efficiency) All three must be high for the well to be produced at optimum conditions.

4. What Should be Known in Order to Analyze a Well?
Recent and/or Representative Well Test
Producing BHP & Static BHP
Dynamometer Data
Pump Capacity (or, Pump Card)
Energy Use
Wellbore Description
Artificial Lift System Description
Fluid Properties
Past History

5. Analyze Well To Determine Efficiencies:
Analyzes the well’s inflow performance to determine if additional production is available. ( >95% Eff. )
Determines the overall electrical efficiency.
Analyzes the efficiency of the pump.
Analyzes the efficiency of the down-hole gas separator.
Analyzes the mechanical loading of rods and pumping unit.
Analyzes performance of prime mover.

6. Well Flow Mechanism Flow Productivity = Flow Rate/ Drawdown
Flow Rate = 250 Bbl/Day
Drawdown = 1000 – 500 = 500 psi
PI= (250 bbl/day)/(500 psi) = 0.5 Bbl/day/psi
1000 psi
500 psi
Flow

7. Determine Well’s Potential using Inflow Performance
= 357 Bbl/D
= 500 Bbl/D

8. Vogel IPR Relationship
PBHP < 10% of SBHP to insure that the well is produced at more than 97% of maximum rate

9. Power Measurement Equipment
Acquire:
RMS (thermal) motor current
Average (real) motor current
kW during a pump stroke cycle.
Three voltage sensing leads “RIGHT",
"CENTER" or
“LEFT".
3. Two current sensors.

10. Electric Power (kW) and Current (Amps) Input to the Motor over the time of One Pump Stroke

11. Analyze System Efficiency2 1
Determine:
Input Kw
PR Hp
Pump Hyd Hp 3

12. Example of Low Surface Efficiency
Bad Tail Bearing Results in Low Surface Efficiency of 66.5%
Before
Surface Efficiency of 83.0% After Repair of Bad Tail Bearing
After

13. Motor Power and Electrical Analysis
Cost $
Power
System Efficiency

14. Use Both Producing Fluid Level Survey and Dynamometer Analysis to Answers the Following Questions:
Is the well being produced at its maximum production rate?
Does a fluid column exist above the pump intake?
Is the pump completely filled with liquid?
Is low efficiency caused by incomplete pump fillage due to over-pumping the well or due to gas interference?

15. Acoustic and Power Surveys Show System Efficiency Less Than 35%
Drawdown
Dynamometer
Your Job
Tubing Leak ?

16. Acoustic and Power Surveys Show System Efficiency Greater Than 35%
Drawdown
Dynamometer
Your Job

17. Low Efficiencies of Sucker Rod Lifted Wells Are Often Caused by Partial Pump Fillage
More efficient operations and lower electrical power usage will result if wells are operated with a pump filled with liquid.
Full pump fillage also requires an efficient downhole gas separation that results in a full pump if sufficient liquid is present to fill the pump.
Full pump fillage generally requires controlling the run time of the pumping unit to match the pump capacity to the maximum well inflow rate.

18. Gaseous Fluid Level Above Pump - Gas Interference
Gaseous Fluid Level Above Pump - Gas Interference ? Increase Efficiency by Improving Downhole Gas Separator
Fo Well
Gas
Interference
Fo Rods

19. Fluid Level @ Pump - Fluid Pound
Fluid Pump - Fluid Pound? Timer or Pump Off Controller Candidate
Fluid Pound

20. Timers and Pump-off Control Systems
Both timers and pump-off control systems can be used to control a pumping unit motor
Timers are preset to turn the motor on and off at specific times
Pump-off Control systems shut down the motor when incomplete pump fillage is detected, then, turn the motor on after a preset elapsed time

21. Pump-off Control System
Monitors pump fillage when the motor is operating
Shuts down the motor when partial pump fillage is detected
After a preset down time, starts the motor and again monitors pump fillage

22. 15 Minute Percentage Timer
Reduce electricity demand charges
Relatively simple to operate
Relatively inexpensive
Should be considered for low cost intermittent pumping unit operation

23. Optimize Efficiency of Well Before Installing TIMER or POC
Is the PBHP low compared to SBHP at all times?
Is the mechanical equipment properly loaded?
Is the pump full of liquid when liquid exists in the casing annulus above the pump?

24. Startup Motor Power
0.7 seconds
normal operation

25. Power Usage During Intermittent Motor Operation
Start up
Pumped Off
Full Pump
Stopped

26. HOW TO MINIMIZE ELECTRICITY USAGE?
Maintain a high pump volumetric efficiency:
Match pumping unit capacity with wellbore inflow.
Pump a Full Stroke of liquid by controlling run time with a POC or Timer
Eliminate Gas interference.
When System Efficiency is low, find and fix problem.
Mechanically/Electrically balance pumping unit.
Properly size pumping unit, rods and pump to match well loads.
On severely over-sized motors where surface efficiency falls below 50%, reduce motor size.

27. Periodically Monitor Well’s Operations To Maintain Efficient Operations
Check pump for proper operation
Produce all available liquid from the Wellbore
Operate well with high volumetric pump efficiency
Use POC or TIMER to reduce run time if pump capacity exceeds production rate

28. High Efficiency Reduces Equipment Operating Costs
Uniform loading of pump and pumping unit reduces maintenance.
Operating the pumping unit a portion of the time subjects the unit to less wear and tear.
Fluid pound should be minimized.
Reduced shock loading results in decreased rod buckling, pump wear, tubing wear, excessive rod loading changes and pumping unit vibration.
Reduction of shock loading reduces maintenance costs.

29. Maintaining High Efficiency in Sucker Rod Lift Operations Results in:
Reduced Electrical Costs
Reduced Mechanical Operating Expense.
Increased in Oil and Gas Production.
Longer Run Times Before Failure.

30. Questions?