Energy Efficiency in On shore Exploration- Oil Pumping Application
Beam pump Controller
Contents
• Beam pump general
• Regeneration control
• ENA System
• Speed control for Beam Pumps and
related problems
• Speed control algorithm
• HMI and messaging
Beam pump – Lay-out
Beam
Horse Head
Crank
Counter Balance Weights
Up Stroke
Down Stroke
Gearbox
Polished Rod
Stuffing Box
Electrical Enclosure
Motor
Position Sensor
Alternative Position
Sensor Location
Sucker Rod Pump
Assembly
Travelling Valve
Plunger
Standing Valve
Reservoir
Beam Pump Controller
Challenges
• Regenerative energy during parts of the pumping
cycle
• Ever changing well conditions require complex
speed regulation algorithm.
• Extreme climatic conditions.
• High starting torque, due to eccentric load
• Retro fit applications make extensive equipment
modifications difficult and application specific
Rod String
Beam Pump Issues/Problems
Changing Well conditions
• Pumps are installed and geared up to
match the well conditions, ensuring
100% pump fill per stroke
• Well capcatity reduces over time
resulting in incomplete filling.
• This results in ineficency and severe
mechanical deteriation.
• Fluid Pound
•Gas Lock
ATV71 – ENA SYSTEM
Regeneration
• During direction transition the motor
will regenerate energy for a short period
of time.
• In a Direct On Line system, this energy
is fed back into the mains.
• Standard Drives, as standard, can not
handle this energy and IGBT’s will be
turned off to protect the drive. This
will result in loss of control.
Zero torque limit
Regeneration occurs during
stroke direction transition
ATV71 ENA System
Regeneration: Common Solutions:
1.
2.
Dynamic Brake Resistors
•
Energy waste because the regenerative energy is transformed to heat
•
Additional equipment
Active Front End
•
No energy waste
•
Expensive
Regeneration: ATV71 ENA feature.
•
The pump speed is adjusted to absorb the regen energy as kinetic energy in the
moving mechanism
•
No additional equipment, no energy waste
•
Economical
ENA System
§ A special Algorythm for Oil pumps
§ Easy to adjust (3 parameters only)
§ No external or additional device to brake the counter weight
§ Energy saving
§ Preserve the mechanics of the system
§ Display with customer unit : hits / minute
§ No motor inductances : shot distance to the pump
Decrease the network consumption
Energy consumed in the network is reduced because of the ENA algorythm. This make a
huge energy saving that can reach 50%.
Line current with a standard system
Line current with Ena System
Beam Pump Issues/Problems
Optimum Operation - 100% Pump fill – No Fluid Pound
Beam Pump Issues/Problems
Non Optimum Operation
50% pump Fill – Fluid Pound and Low Efficiency
Beam Pump Issues/Problems
Low Pump Fill - Energy Waste:
100% pump fill
•
Torque profile on the up stroke is the same for 100% and 50% pump fill (Energy required in both cases is N)
•
Torque on the down stroke is different, because the travelling valve is closed as the plunger travells through gas.
(Energy required for the 100% pump fill is N, Energy required for the 50% pump fill is N/2)
•
The total energy required for one stroke is N+N=2N for 100% pump fill and N+N/2=1.5N for 50% pump fill
The total Energy consumed in one stroke is NOT proportional to pump fill level!
Over 30% Energy waste can occur!
Beam Pump Issues/Problems
Gas Lock
• Gas Lock results from very low pump fill.
• On the down stroke the standing valve is closed. The travelling valve
also remains closed. The gas is compressed,.. On the way up, the gas
expands and again both valves remain closed.
• The plunger travels up and down without pumping oil. The result is
energy waste, production loss and mechanical wear as the plunger is
now un-lubricated
ATV71 RodMax – Pump Fill Controller
Pump Fill Controller Block. Block Diagram:
Motor Torque
Zero
HighPosition
LowPosition
Span
Pump Energy
Consumption
Prox Switch
Motor Speed
Rod Position
Calculator
Pump Fill Calculator
Span & Zero setup via RMO
High Level
Pump Fill
Comparator
+
Low Level 1
0
Adjust Rate/Stroke
Speed Adjust
Algorithm
Low Level 2
-
Minimum Speed
Speed Reference
--
ATV71 – messaging
Messaging. providing full system operation feedback
• Stroke
Length Monitoring. Monitors belt slippage, switch failure. (the PFC is disabled
and an alarm is generated)
•System status (starting, pumping, direction, short or long cycle, wait)
•Energy Meter displays the estimated KWh consumed by the drive.
•Minimum and maximum achieved pump fill level.
• Hours run counter for maintenance purposes.
•Balance display indicates the balance of the counter weights.
•Motor and Drive thermal state
•Crank position in degrees or %
•Pump Torque and Speed
•Real date and time
RodMax Optimiser
Dynamometer Display Used to calibrate the Pump Fill Controller.
Start / stop plot
Display / hide
up stroke
Pump Information
Use of standard motors
ENA permit the utilization of standard 4 poles motors instead of highly isolated motors like Nema B that are more expensive.
4 Polos
1450 RPM
Advantages of ENA system with Altivar 71
§ Cost cutting : no motor inductances,
braking resistors
no
THANK YOU