System Efficiency of Sucker Rod Pumping

Sucker Rod Pumping WorkshopWyndham Hotel, Houston, Texas

September 11 – 14, 2007

System Efficiency of System Efficiency of Sucker Rod PumpingSucker Rod Pumping

Lynn Rowlan

Sept. 11 - 14, 2007 2007 Sucker Rod Pumping Workshop 2

EfficiencyEfficiency1.1. Power Input into Sucker Rod Lift SystemPower Input into Sucker Rod Lift System

a)a) System Does Works to Add Energy to FluidsSystem Does Works to Add Energy to Fluids

b)b) Fluids then flow to the SurfaceFluids then flow to the Surface

2.2. Discuss Surface & System efficiencyDiscuss Surface & System efficiency3.3. Use Fluid Level, Dynamometer, and Power Use Fluid Level, Dynamometer, and Power

Surveys to Determine Efficiency Surveys to Determine Efficiency 4.4. Low Efficiency Used to Identify ProblemsLow Efficiency Used to Identify Problems5.5. How to maintain a high producing efficiency in How to maintain a high producing efficiency in

sucker rod lift operationssucker rod lift operations


Net LiftNet Lift ~ ~ System Efficiency EquationSystem Efficiency Equation

Liquid Level

1 HHP = 27 BPD x 5000 Ft1 HHP = 27 BPD x 5000 Ft


Net LiftNet Lift ~ ~ System Efficiency EquationSystem Efficiency EquationUse to Identify Wells Having Low System EfficiencyUse to Identify Wells Having Low System Efficiency


Measure Motor Input = 13.9 kWMeasure Motor Input = Measure Motor Input = 13.9 kW13.9 kW

Acquire:Acquire:•• RMS (thermal) motor currentRMS (thermal) motor current•• Average (real) motor currentAverage (real) motor current•• kW during a pump stroke cycle.kW during a pump stroke cycle.


Fo Rods

Fo Well

Pump Intake Pressure = 730.7 Psig 133 BOPDTubing Fluid Gradient = 0.335 psi/ft 241 BWPDPump Depth = 5059 ft

Pump Intake Pressure = 730.7 Psig 133 BOPDPump Intake Pressure = 730.7 Psig 133 BOPDTubing Fluid Gradient = 0.335 Tubing Fluid Gradient = 0.335 psipsi/ft 241 BWPD/ft 241 BWPDPump Depth = 5059 ftPump Depth = 5059 ft

GasGasInterferenceInterference

Net LiftNet Lift94 Ft?94 Ft?


Determine:

1. Input Kw

2. PR Hp

3. Pump HydHp

1

2

3

Surface Efficiency 1-2

System Efficiency 1-3


System Efficiency CalculationSystem Efficiency CalculationTheoretical amount of work required to lift the Theoretical amount of work required to lift the liquid from the intake pressure at the pump to liquid from the intake pressure at the pump to the surface divided by the energy supplied to the the surface divided by the energy supplied to the motor.motor.

Measure:Measure:•• Pump Intake Pressure from Acoustic Liquid LevelPump Intake Pressure from Acoustic Liquid LevelNet Lift = P DepthNet Lift = P Depth––PIP/ .433xSG= 5059 PIP/ .433xSG= 5059 –– 730/0.335 = 730/0.335 = 2880 ft2880 ft•• Fluid Volumes and PropertiesFluid Volumes and Properties•• Motor Input Power MeasurementMotor Input Power Measurement


55% System Efficiency55% System Efficiency


Why is Efficiency a Useful Benchmark?Why is Efficiency a Useful Benchmark?•• Measure of work input (power Measure of work input (power

requirements) relative to useful output requirements) relative to useful output (liquid production).(liquid production).

•• Directly related to operating costsDirectly related to operating costs•• Relatively easy to measureRelatively easy to measure•• Generally accepted guidelinesGenerally accepted guidelines

EfficiencyEfficiencySystem Efficiency should be > 50% System Efficiency should be > 50% Surface Efficiency should be > 80%Surface Efficiency should be > 80%


Power, Fluid Level and Dynamometer Power, Fluid Level and Dynamometer Surveys Answers Following Questions:Surveys Answers Following Questions:

1.1. Is the well being produced at its maximum Is the well being produced at its maximum production rate?production rate?

2.2. Does a fluid column exist above the pump Does a fluid column exist above the pump intake? intake?

3.3. Is the pump completely filled with liquid? Is the pump completely filled with liquid? 4.4. Is Is low efficiencylow efficiency caused by incomplete pump caused by incomplete pump

fillage due to overfillage due to over--pumping the well or due pumping the well or due to gas interference?to gas interference?


Acoustic and Power Surveys ShowAcoustic and Power Surveys ShowSystem Efficiency Less Than 35%System Efficiency Less Than 35%

Tubing Leak ?


Acoustic and Power Surveys ShowAcoustic and Power Surveys ShowSystem Efficiency Greater Than 35%System Efficiency Greater Than 35%


System Efficiency Equation using PIPSystem Efficiency Equation using PIPUse to Identify Wells Having Low System EfficiencyUse to Identify Wells Having Low System Efficiency


What Should be Known in Order to Determine the Efficiency of a Well?What Should be Known in Order to What Should be Known in Order to Determine the Efficiency of a Well?Determine the Efficiency of a Well?

•• Recent and/or Representative Well TestRecent and/or Representative Well Test•• Fluid PropertiesFluid Properties•• RunRun--TimeTime•• Producing Fluid Level ~ Producing Fluid Level ~

Pump Intake PressurePump Intake Pressure•• Dynamometer Data (Representative)Dynamometer Data (Representative)•• WellboreWellbore DescriptionDescription


Losses ~ System EfficiencyLosses ~ System Efficiency

Input HP = Kw/0.746Input HP = Kw/0.746 OutputOutput


Motor Performance Data – Efficiency vs. Output Hp Comparison of NEMA D MotorsMotor Performance Data Motor Performance Data –– Efficiency vs. Output Hp Efficiency vs. Output Hp Comparison of NEMA D MotorsComparison of NEMA D Motors


60 Hp NEMA D Motor (Surface Efficiency) Motor Performance Data – Efficiency vs. Output Hp60 Hp NEMA D Motor (Surface Efficiency) 60 Hp NEMA D Motor (Surface Efficiency) Motor Performance Data Motor Performance Data –– Efficiency vs. Output HpEfficiency vs. Output Hp

Other Motor Manufacturers Efficiency may be DifferentOther Motor Manufacturers Efficiency may be Different


Motor Performance –NEMA D MotorsMinimum Surface EfficiencyMotor Performance –NEMA D MotorsMinimum Surface Efficiency

Surface EfficiencySurface Efficiency measured measured over one revolution of the over one revolution of the crank is an excellent crank is an excellent indicator of the operating indicator of the operating performance of the surface performance of the surface equipment. equipment.

Surface EfficiencySurface Efficiency includes includes losses per crank revolution losses per crank revolution in in wirelineswirelines, structural , structural bearings, transmissions, Vbearings, transmissions, V--belts, and the electric motor.belts, and the electric motor.


Example of Low Surface EfficiencyExample of Low Surface EfficiencyExample of Low Surface Efficiency

Surface Surface Efficiency Efficiency of of 83.0%83.0%

After After Repair of Repair of Bad Tail Bad Tail BearingBearing

Bad Tail Bad Tail Bearing Bearing Resulted Resulted in Low in Low Surface Surface

Efficiency Efficiency of of 66.5%66.5%

AfterAfter

BeforeBefore


Low Efficiencies of Sucker Rod Lifted Wells Are Often Caused by Partial Pump FillageLow Efficiencies of Sucker Rod Lifted Wells Low Efficiencies of Sucker Rod Lifted Wells Are Often Caused by Partial Pump FillageAre Often Caused by Partial Pump Fillage

•• More efficient operations and lower electrical More efficient operations and lower electrical power usage will result if wells are operated power usage will result if wells are operated with a with a pump filled with liquidpump filled with liquid..

•• Full pump Full pump fillagefillage also requires an also requires an efficient efficient downholedownhole gas separationgas separation that results in a full that results in a full pump if sufficient liquid is present to fill the pump if sufficient liquid is present to fill the pump.pump.

•• Full pump fillage generally requires Full pump fillage generally requires controlling controlling the run timethe run time of the pumping unit to match the of the pumping unit to match the pump capacity to the maximum well inflow rate.pump capacity to the maximum well inflow rate.


Drawn Down and Pump has Incomplete Fillage?Timer or Pump Off Controller CandidateDrawn Down and Pump has Incomplete Drawn Down and Pump has Incomplete FillageFillage??Timer or Pump Off Controller CandidateTimer or Pump Off Controller Candidate

Fluid Fluid PoundPound


Timers and Pump-off Control SystemsTimers and PumpTimers and Pump--off Control Systemsoff Control Systems

•• Both timers and pumpBoth timers and pump--off control systems off control systems can be used to control a pumping unit motorcan be used to control a pumping unit motor

•• Timers are preset to turn the motor on and off Timers are preset to turn the motor on and off at specific timesat specific times

•• PumpPump--off Control systems shut down the off Control systems shut down the motor when incomplete pump fillage is motor when incomplete pump fillage is detected, then, turn the motor on after a detected, then, turn the motor on after a preset elapsed timepreset elapsed time


Startup Motor PowerStartup Motor Power

0.7 seconds0.7 seconds

normal operationnormal operation


Startup Motor Power ConsumptionStartup Motor Power Consumption

1.1. During startDuring start--up a beam pump motor up a beam pump motor uses approximately 3 times full load uses approximately 3 times full load power for about 0.7 seconds.power for about 0.7 seconds.

2.2. Electricity usage during startElectricity usage during start--up is less up is less than electricity usage during one stroke than electricity usage during one stroke of normal operation.of normal operation.


How to Operate with High Efficiency?How to Operate with High Efficiency?How to Operate with High Efficiency?

•• Maintain a high pump volumetric efficiency:Maintain a high pump volumetric efficiency:

1.1. Match pumping unit capacity with wellbore inflow.Match pumping unit capacity with wellbore inflow.

2.2. Pump a Full Stroke of liquid by controlling run time with a Pump a Full Stroke of liquid by controlling run time with a POC or TimerPOC or Timer

3.3. Eliminate Gas interference.Eliminate Gas interference.

•• When System Efficiency is low, find and fix problem. When System Efficiency is low, find and fix problem.

•• Mechanically/Electrically balance pumping unit.Mechanically/Electrically balance pumping unit.

•• Properly size pumping unit, rods and pump to match well Properly size pumping unit, rods and pump to match well loads.loads.

•• On severely overOn severely over--sized motors where surface efficiency falls sized motors where surface efficiency falls below 50%, reduce motor size.below 50%, reduce motor size.


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Other uses of this presentation are prohibited without the expressed written permission of the company(ies) and/or author(s) who own it and the Workshop Steering Committee.


DisclaimerThe following disclaimer shall be included as the last page of a Technical Presentation or Continuing Education Course. A similar disclaimer is included on the front page of the Sucker Rod Pumping Web Site.The Artificial Lift Research and Development Council and its officers and trustees, and the Sucker Rod Pumping Workshop Steering Committee members, and their supporting organizations and companies (here-in-after referred to as the Sponsoring Organizations), and the author(s) of this Technical Presentation or Continuing Education Training Course and their company(ies), provide this presentation and/or training material at the Sucker Rod Pumping Workshop "as is" without any warranty of any kind, express or implied, as to the accuracy of the information or the products or services referred to by any presenter (in so far as such warranties may be excluded under any relevant law) and these members and their companies will not be liable for unlawful actions and any losses or damage that may result from use of any presentation as a consequence of any inaccuracies in, or any omission from, the information which therein may be contained.The views, opinions, and conclusions expressed in these presentations and/or training materials are those of the author and not necessarily those of the Sponsoring Organizations. The author is solely responsible for the content of the materials.The Sponsoring Organizations cannot and do not warrant the accuracy of these documents beyond the source documents, although we do make every attempt to work from authoritative sources. The Sponsoring Organizations provide these presentations and/or training materials as a service. The Sponsoring Organizations make no representations or warranties, express or implied, with respect to the presentations and/or training materials, or any part thereof, including any warrantees of title, non-infringement of copyright or patent rights of others, merchantability, or fitness or suitability for any purpose.

System Efficiency of Sucker Rod Pumping

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