Pump-Off Control (POC)

Topics

How Pump-Off Control Works

Morning Report

Other Report

Dynagraph Control Cards

Parameter Setup

Field Descriptions: Parameter Setup

Read Write Registers

Time Synchronization

How Pump-Off Control Works

Pump-Off control has been established as a tried and proved technology. Controllers have been operating in a number of fields worldwide for over three decades. Several major and independent oil companies involved with pump off control applications since the early 1970s have resoundingly committed to the re-use of this technology.

Economic Benefits

Economic analysis indicates typical payout of the associated capital investment within a year, with the average payout averaging about 6 months. Much shorter payouts have been observed for some projects. By using pump off controllers, customers can realize significant economic benefits :

Note: Estimated cost for tubing repair ranges from $2M to $6M per job, depending upon well depth. Estimated cost for rod failures ranges from $1M to $4K per job, depending on well depth.

How Pump-Off Controllers Work

Most Pump-Off Controllers are remote terminal units (RTUs), utilizing microprocessors capable of autonomous operation of rod pumped wells. They monitor pump conditions, usually by continuous measurement of load on the pumping unit and take action based on pre-set conditions managed by the operator. When pump-off is detected, the pumping unit is shut down for a pre-set time period to allow sufficient entry of fluid into the well bore for optimized pump performance.

Our pump-off controller monitors two fundamental parameters: load and position.

Load Monitoring

Two types of devices can be used to obtain load information: Beam Transducers and Load Cells.

Either type of load transducer will function suitably for pump-off control and well analysis activities.

Position Monitoring

The position of the beam can be derived by using a proximity switch to monitor counterweights, a mercury tilt switch, a resistive pot mounted underneath the walking beam, or an inclinometer mounted directly to the walking beam. Proximity switches are sufficient for low cost controllers, although POC systems based on proximity switches tend to assume that up strokes and down strokes are of equal duration, which in most cases is true.

Ease of Deployment

AuraPump RTUs are inexpensive yet reliable. You can pick from a large variety of communication options to find the one which best suit your needs. If a radio infrastructure is in place, we will utilize it. If a cell phone or cellular digital packet data (CDPD) is best, then it can be used as well. For those who need view capability, we can use a local connection to an Internet Service Provider (ISP) and transmit the data to our centralized collection center for re-distribution worldwide.

You can monitor and configure your controller remotely using your web browser. You can also view a Morning Report on the web site that provides well status, run time data, and other information.

Metrix Technologies offers the services of an artificial lift specialist who can assist you in the adjustment of control parameters and the interpretation of pump cards. In addition to training, which is provided at no charge, you can obtain assistance with complex or time-consuming issues for a nominal fee.

Operational Software

Our POC has comprehensive firmware (RTU imbedded software) that allows a straightforward user interface, through a standard keypad and alphanumeric display, to the actual device. The keypad and display provide the operator with access to all registers required to calibrate and maintain the POC.

In addition, you can use a laptop-based software package to program and troubleshoot the controller in the field.

 


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Pump-Off Control Morning Report

The EFM Morning Report provides a snapshot of what's going on at the gas well. It has the latest readings as well as readings for the last 5 days to show the following:

To view the Morning Report:

1.  Log in to the Field Data system.

2.  Click on the Pump-Off Control button.

3.  Click on the Morning Report tab. The Morning Report displays.

 


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Pump-Off Control Other Reports

This function provides access to reports stored in the RTU. Reports include:  

To view the POC Other Reports:

1.  Log in to the Field Data system.

2.  Click on the Pump-Off Control button.

3.  Click on the Other Reports tab.

4.  Click on the report you want to view.

5.  In the Well field, click on the down arrow to select the well.

6.  Click on the Build the Report >> button.

 


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Pump-Off Dynagraph Control Cards

This function provides access to dynamometer cards stored in the RTU.

To access the Pump-Off Control Cards window:

1.  Log in to the Field Data system.

2.  Click on the Pump-Off Control button.

3.  Click on the Cards tab. The Pump-Off Control Dynagraph Cards window displays.

4.  In the Well field, click on the down arrow and select the well.

5.  Click the Retrieve the Card >> button. A Realtime Report displays.

 


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Pump-Off Control Parameter Setup

This function allows you to set the basic operating parameters of the RTU.

To access Pump-Off Control Parameter Setup window :

1.  Log in to the Field Data system.

2.  Click on the Pump-Off Control button.

3.  Click on the Setup tab.

4.  Click on Parameters. The Pump-Off Control Parameter Setup window displays.

5.  In the Well field, click on the down arrow and select the well.

6.  Click the appropriate button to select Stored Parameters or Live Parameters.

7.  Fill in the Parameter values. See Field Descriptions.

8.  Click one of the following buttons:

 


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Field Descriptions: Pump-Off Control Parameter Setup

Parameter Values

Off Time

Sets the time in minutes the RTU allows for build up.

Pump Up Time

Sets the time in minutes the RTU runs the well before checking for pump-off.

Off Time High Limit

Sets the maximum Off Time minutes the RTU can use when adjusting the Off Time.

Off Time Low Limit

Sets the minimum Off Time minutes the RTU can use when adjusting the Off Time.

Production Timer

Sets the number of minutes the RTU will run the well during each cycle if it is in the manual production timer mode.

Load Offset

Sets the offset pounds the RTU will add to the load.

Load Gain

 Sets the gain applied to the raw load reading to convert it to pounds.

Report Time

 Sets the hour (AM) at which gauge off will be done.

Function Values

This window allows you to enter Limit, Action, and Delay values for the indicated Functions.

Pump Off Limit

 

Pump Off Delay

Sets the number of pump-off strokes the RTU must see before it takes the PUMP OFF action.

Malfunction Limit

 Sets the minimum difference between PPRL and MPRL allowed.

Malfunction Delay

Sets the number of malfunction strokes which must occur before the MALFUNCTION action is taken.

High Load Limit

Sets the maximum PPRL allowed.

High Load Delay

Sets the number of strokes during which the load must exceed the HIGH LOAD LIMIT before the HIGH LOAD ACTION is taken.

Low Load Limit

Sets the minimum MPRL allowed.

Low Load Delay

Sets the number of strokes during which the load must go below the LOW LOAD LIMIT before the LOW LOAD ACTION is taken.

Peak Load Limit

Sets the maximum PPRL allowed.

Run Time Limit

Sets the maximum number of minutes the well can run in a day without causing the MAXIMUM RUNTIME ACTION to be taken.

 


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Pump-Off Control Read and Write Registers

This function allows you to Read or Write directly to RTU registers.

To access the Pump-Off Control Read and Write Registers window:

1.  Log in to the Field Data system.

2.  Click on the Pump-Off Control button.

3.  Click on the Setup tab.

4.  Click on Registers. The Pump-Off Control Read and Write Registers window displays.

5.  In the Well field, click on the down arrow and select the well.

6.  In the Register field, enter the register you want to read or write to.

Note: Register 1 is restricted from remote modification.

7.  In the Count field, enter the number of registers you want to display.

8.  To read a register, click the Read button. To write to a register, click the Write button.

9.  Register List

Register Register Name Description
1 RTU Address The address to which the RTU will respond to a 
    Range 1 to 255  Default 1
    (The 255 limit is established by the MODBUS protocol)
     
2 Transmit delay time Allows radio to transfer from receive to transmit  mode.
    Range 0 to 1000 mSec Default 100 mSec
     
3 Report time The AM time of day at which the controller
    calculates all daily functions
    Range 1 to 11   Default 7
     
4 Load Gain The number of pound per A/D count, the rated load of the transducer divided by 255
    Range 1 to 255   Default 1
     
5  Load offset factor The number of pounds that the load transducer reads with no load applied
    Range 255  Default 1
     
6 Off Time The starting off time, the time that  the well will be shut in after a control 1 or 4
    Range 1 to 65000  Default 15
     
7 Pump Up Time The time, in minutes, at the beginning of pumping cycle during which pump off control
  Range 0 to 65000  Default 1  
     
8 Manual on time On time, in minutes, for manual timer mode
  Range 0 to 65000  Default  10  
     
9 Start int. P1 Start integration, in % of down stroke
  Range 0 to 99.9   Default 0  
     
10 End int. P2 End integration, in % of down stroke
  Range 0 to 99.9     Default 25  
     
11 Integration Reff. The reference for integration,  as a percentage of PPRL
  Range 0 to 99.9     Default 62  
     
12 Force Force an action to occur
     
13 Configuration Sets the operation of the position signal
    1  select analog position signal
    2  select digital position signal
    4  invert position signal
    8  save sequence numbers with load readings (peak load)
    16 reverse control action
    128 load reference % of load range
    200 Turn on simulator
     
14 Start Well Enter 1 into register 14
     
15 Scroll Rate Sets the rate at which the automatic scroll operates.  Larger numbers slow the rate.
     
16 Pump off Limit The load set point, in pounds, for pump off
  Range 0 to 60000  Default 15000  
     
     
17 Pump off Delay The number of consecutive strokes that a pump off  violation must be detected before a control action is issues
    Range 0 to 65000  Default 0
     
18 Pump off action The desire control action pump-off
    Range 0 to 8  Default 1
     
19 Rod Part Limit The load range, in pounds, below which a  malfunction will be declared
    Range 0 to 60000 Default 30000
     
20 Rod Part count The number of consecutive strokes that  a malfunction violation must be detected before a control action is issued
    Range 0 to 65000  Default 2
     
21 Rod part action The desired control action for malfunction
    Range 0 to 8    Default 5
     
22 High load limit The high polished rod load, in pounds at which a control action will be issued
    Range 0 to 60000  Default 60000.
     
23 High load delay The number of consecutive strokes that a high load must occur to cause a control to
     
24 High load action The desired action for high rod load
    Range 0 to 8   Default 8
     
25 Low load limit The low polished rod load, in pounds, at which a control action will be issued
    Range 0 to 60000  Default 0
     
26 Low load delay The number of consecutive strokes that a low load must occur to cause a control to be issued
     
27 Low load action The desired action for low rod load
    Range 0 to 8  Default 8
     
30 Long run time limit The time, in minutes, in a day which will  cause a control action to be issued
    Range 0 to 1440 Default 1440
     
31 Run time action The desired control action for long run time   
    Range 0 to 8  Default 3
     
36 Current Gas Press The scaled value of the current gas meter pressure.
     
37 Current D/P The scaled value of the current differential pressure across the gas measurement orifice plate
     
38 Current Temp The scaled value of the temperature of the gas being measured.
     
39 Liquid flow rate The flow rate through the turbine meter in Barrels per Day.
     
40 Liquid flow Volume The accumulated volume of flow through the turbine meter.
     
41 Orifice Diameter The bore diameter of the orifice plate in 1/1000 of an inch.
     
42 Tube Diameter The diameter of the meter tube in 1/1000 of an inch.
     
43 Gas Press Full Scale The scaling factor for the maximum pressure of the pressure transmitter in PSI.
     
44 DP full scale The scaling factor for the maximum D/P of the D/P transmitter in inches of water.
     
45 Temp full scale The scaling factor for the maximum temperature of the temperature transmitter in EF.
     
46 Temp at 1 V The temperature that will produce a 1 VDC output from the temperature transmitter.
  CSG press full scale The scaling factor for the maximum pressure of the casing pressure transmitter in PSI.
     
48 Turbine mtr PPG The  calibration factor for the turbine meter in pulses per gallon.
     
49 Calibrate gas Control the operation of the gas calibration bypass mode.  1 places the controller in
     
50 Use Temp input Write a 1 in this register to activate the analog temperature input.  Write a 0 in this
     
51 Use NX19 Write a 1 in this register to activate the use of NX19 for Supercompressibility
     
57 Position gain Pounds per A/D count
     
58 Off time high limit The maximum allowable off time, in minutes the automatic down time algorithm may
  Range 0 to 65000  Default 30 not  set a down time that will exceed this limit.
     
59 Off time Low limit The minimum allowable off time, in minutes
  Range 0 to 65000  Default 10  
     
60 Autozero Limit Set﷓point for Autozero ﷓ Use with beam mounted load transducer only        
     
61 Autozero action The control action to be taken if the controller is unable to cause the peak load to
     
62 Auto zero value The value of the signal sent from the microprocessor to the Autozero D/A converter
     
65 Digital output status The contents of register 65 indicates the current status of the controller, as
    Motor on                                  0
    Motor off                                  1
    Alarm on                                  2
    Alert on                                    4
    Horn on                                    8
    Automatic mode                     256
    Manual Mode                         512
    Production timer Mode           1024
    Manual timer mode                2048
     
    Example: the motor is off         1
    The alarm is on                       2
    The controller is in Auto.          256
    The display reads                    259
     
66 POC Status The contents of register 66 indicates the  operating condition of the well as follows:
    In pump up time                      1
    In normal run                          2
    Pumped off                             4
    Malfunction                            8
    High rod load                        16
    Low rod load                         32
    Stuck pump                           64
    Auto Zero Fault                    128
    Unit imbalance                     256
    Long run time                       512
    Production timer                 1024
    Manual timer                      2048
    Failed position transducer     4096
    Failed load transducer          8162
    Cable failure                      16384 
     
69 Minutes into crnt cycle The number of minutes into the current  cycle, ie. downtime, pump up time, run time
     
70 Stroke period The stroke period, in 0.1 seconds
     
71 Result of integration The integrated value of load and position
     
72 CardA  
     
73 CardB  
     
74 Flag  
    0 = buffer A     1 = buffer B
     
75 Run time today The time, in 0.1 hrs, the well has run today
     
76 Off time today The time, in 0.1 hrs, the well has bee off today
     
77 Total run time The total cumulative Run time
     
78 MAX load  
     
79 Max load today The highest rod load today
     
80 MIN load  
     
81 Min load today The lowest rod load today
     
82 Load input The value of the A/D converter on the load analog channel
     
83 Position input The value of the A/D converter on the position analog channel
     
84 AUX 1  
     
85 AUX 2  
     
86 AUX 3  
     
87 AUX 4  
     
88 AUX 5  
     
89 AUX 6  
     
90 Digital input Digital input #1   Closed contact = 1
     
91 Digital output Closed contact = 1,2,4,8
     
95 Average run time The run time to run in the production timer mode.  This value is calculated from the
     
    For time tag information the number displayed is the decimal value of the hex
     
97   Year
     
98   Month
     
99   Date
     
100 Day  
     
101 Hour  
     
102 Minute  
     
103 Second The current second of the minute  00﷓59 BCD
     
104 Clock calendar control  
     
113 Last cycle time The run time, in 0.1 minutes, for the last pumping cycle.  The historical cycle times are
     
     
145 Last run time The run time, in 0.1 hours, for the previous day.  The historical daily run times are
     
177 PPRL  
     
209 Last start Time tag for last start initiated by the controller.
     
213 Last stop Time tag for the last stop initiated by the controller.
     
217 Last power off Time tag for the last time AC power was removed from the controller
     
221 Last power on Time tag for the last time that AC power was applied to the controller
     
225 Last malfunction Time tag for the last time that the controller detected a malfunction
     
229 Last edit Time tag for the last time that the
     
233 Last Alarm Time tag for the last alarm occurrence
     
237 Last High Load Time tag for the occurrence of the highest rod load measured by the controller
     
241 Last low load Time tag for the occurrence of the lowest
     
245 Msg Recevd The total number of messages received by the controller
     
246 Good CRC The total number of messages received by the controller with a CRC correct for the
     
250 Baud Rate The communications baud rate for  the controller.  0=1200 baud   600= 600 baud.

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Pump-Off Control Time Synchronization

This function allows you to read and reset the RTU real time clock.

To access the Pump-Off Control Time Synchronization window:

1.  Log in to the Field Data system.

2.  Click on the Pump-Off Control button.

3.  Click on the Setup tab.

4.  Click on Time. The Pump-Off Control Time Synchronization window displays.

5.  In the Well field, click on the down arrow and select the well.

6.  Click the Retrieve Time >> button.

7.  To synchronize the time, click the Synchronize button.

 


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