EP3816444A1 - Method for determining operating properties of a rod borehole pump and pump system for same - Google Patents

Abstract

Method for determining the operating properties of a rod pump (1), comprising a pump head (110) which is connected to a kinematics converter (120) via a rod (5, 10), and the kinematics converter (120) is driven by an electric motor (3), and furthermore a detection means (130) is provided to detect the power consumption of the motor (3) during its operation, comprising the steps: a) Detection of the current consumption and the operating voltage of the motor (3) via at least one pumping cycle to which four operating phases of the deep pump (1) can be assigned and from this determining the power consumption of the motor (3), b) determining for a pumping cycle a period duration and a maximum of the power consumption which corresponds to the maximum torque of the deep pump ( 1) corresponds, c) determining a reference phase angle for the kinematic converter (120) using the properties of the kinematic converter (120) and the power consumption of the motor (3), d) Erm averaging a torque curve from the power consumption of the motor (3) using the properties of the kinematic converter (120), e) determining the operating properties of the feed pump (1) from the torque curve using the period duration and reference phase angle.

Description

The invention relates to a method for determining the operating properties of a rod pump, comprising a pump head which is connected to a kinematics converter via a rod and the kinematics converter is driven by an electric motor.

The invention also relates to a pumping system with a rod pump, comprising a pump head, which is connected to a kinematic converter via a rod, and the kinematic converter is driven by an electric motor.

Deep pumps are used as conveying devices for the extraction of liquids stored underground when the reservoir pressure is not sufficient for them to reach the surface independently or in sufficient quantities. Most of them are used to produce crude oil. Other areas of application are the promotion of brine and medicinal waters.

The image of most oil fields is dominated by rod pumps, which because of their appearance and their movement are also called horsehead pumps, nickers or nickers. The actual pumping mechanism - a piston with check valves - is located in a separate pipe string in the borehole near the oil-bearing layer. The piston is set in a continuous up and down movement by means of a screwable rod from a pump bracket located on the earth's surface. This is done by what is known as the horse's head. This consists of a segment of a circular arc arranged as a balancer, to which a pair of steel cables or chains is clamped at the top.

The drive is mostly electric. In the presence of sufficient energy-containing gases dissolved in the petroleum, However, some of these gases can be separated from the material to be conveyed on the spot by means of a degasser and fed to a gas engine that drives the pump.

Depending on the type and size of the pump, the working stroke is 1 to 5 m. Two and a half to twelve strokes per minute are common. The rod-type deep pump can be used economically up to a delivery depth of around 2500 m. For greater depths, other pump systems are better suited due to the great weight of the liquid column to be lifted.

The "Mark II" pump type from the Texan manufacturer Lufkin Industries is particularly suitable for high pumping rates from great depths thanks to its special movement geometry.

The "Sucker Rod" type of pump has a sucker rod, a steel rod typically between 25 and 30 feet in length and threaded at both ends, used in the oil industry to support the surface and downhole components of a reciprocating pump installed in an oil well to connect with each other.

An extremely valuable tool for analyzing downhole performance is a downhole test rig, which measures the load on the polished rod relative to the position of the polished rod.

With dynamometers, the rod position and rod load can be recorded over time. The load measuring part of the dynamometer is attached to the polished rod so that the load can be recorded and sent to a recorder. An accompanying part of the dynamometer attached to the walking beam records the position of the polished rod and sends it to the same recorder. The generated graphic is referred to as a Dynagraph or more often as a dynamometer or Dynagraph map and corresponds to a load-displacement diagram.

Dynamometer cards taken from the surface can rarely be used directly to record the operating conditions of the downhole pump, as they also reflect all forces (static and dynamic) that occur from the pump to the wellhead. However, if there is a dynamometer directly above the pump, the recorded map is a real indicator of the pump's operation. Gilbert's Dynagraph (a mechanical dynamometer) succeeded in doing this in the 1930s. Rod loads immediately above the pump, recorded as a function of pump position, give Dynagraph maps a name that distinguishes them from surface maps. Although the use of Gilbert's Dynagraph allowed direct investigation of pumping problems, the practical implications of having the instrument run in the well far outweighed its benefits.

So far, sensors have been used to record the operating conditions of a rod pump, which record the forces acting or the current position (inclination) of the beam (English "beam" or "cranck arm"), for example by force sensors, Hall sensors or Proximity sensors. The position of the boom is calculated from this. However, it is time-consuming to calibrate the respective sensors with one another. In addition, inaccurate calibration can lead to errors which can adversely affect the evaluation of the measurement data.

The object of the invention is to provide a method and a device for determining the operating properties of a rod pump, which simplifies the detection of the operating conditions and at the same time the measurement data are recorded more precisely than is known in the prior art.

1. a) Erfassen der Stromaufnahme und der Betriebsspannung des Motors in Form von diskreten Messpunkten über zumindest einen Pumpzyklus, welchem jeweils vier Betriebsphasen der Tiefpumpe zugeordnet werden können, und daraus Bestimmen der Leistungsaufnahme des Motors,
2. b) Bestimmen für einen Pumpzyklus einer Periodendauer und eines Maximums der Leistungsaufnahme, welches dem Drehmoment-Maximum der Tiefpumpe entspricht,
3. c) Bestimmen eines Bezugsphasenwinkels für den Kinematik-Wandler mithilfe der Eigenschaften des Kinematik-Wandlers und der Leistungsaufnahme des Motors, welcher den Zusammenhang zwischen dem Maximum der Leistungsaufnahme und dem Maximum der auf das Gestänge der Tiefpumpe wirkenden Kraft beschreibt,
4. d) Ermitteln eines Drehmoment-Verlaufs aus der Leistungsaufnahme des Motors mithilfe der Eigenschaften des Kinematik-Wandlers,
5. e) Bestimmen der Betriebseigenschaften der Förder-Pumpe aus dem im Schritt d) ermittelten Drehmoment-Verlauf unter Verwendung der im Schritt b) bestimmten Periodendauer und dem im Schritt c) bestimmten Bezugsphasenwinkel.

The object according to the invention is achieved by a method of the type mentioned at the beginning, with a detection means it is intended to record the power consumption of the motor during its operation, comprising the steps:

1. a) recording the current consumption and the operating voltage of the motor in the form of discrete measuring points over at least one pumping cycle, to which four operating phases of the deep pump can be assigned, and from this determining the power consumption of the motor,
2. b) determining for a pumping cycle a period duration and a maximum of the power consumption, which corresponds to the maximum torque of the deep pump,
3. c) Determination of a reference phase angle for the kinematic converter using the properties of the kinematic converter and the power consumption of the motor, which describes the relationship between the maximum power consumption and the maximum force acting on the linkage of the deep pump,
4. d) Determining a torque curve from the power consumption of the motor using the properties of the kinematic converter,
5. e) Determining the operating properties of the delivery pump from the torque curve determined in step d) using the period duration determined in step b) and the reference phase angle determined in step c).

This means that no further sensors, which have to be attached to the pump, are required to determine the operating properties of the delivery pump.

Furthermore, there is no need for complex calibration of such sensors with one another.

In addition, the accuracy in determining the operating characteristics of the feed pump can be increased.

The discrete measuring points of the current consumption of the motor are recorded with a sufficiently high sampling frequency.

The operating voltage supply for the motor can have one or more phases.

In a further development of the invention, it is provided that the period duration is determined with the aid of an approximated polynomial through the power values of the measuring points.

This enables the operating properties of the feed pump to be precisely determined in a simple manner.

In a further development of the invention, it is provided that the period duration is determined with the aid of a polynomial which takes into account statistical mean values of the power values of the respective measuring points over at least five, preferably at least ten, particularly preferably at least fifty pump cycles for support points of the polynomial.

This enables the operating properties of the feed pump to be precisely determined in a simple manner.

In a further development of the invention, it is provided that a reference value is determined for the measuring points, at which a maximum is present for the change in the respective power value between two immediately successive measuring points, and the period duration is determined with the aid of the reference value.

This enables the operating properties of the feed pump to be precisely determined in a simple manner.

In a further development of the invention, it is provided that the determination of the operating properties of the delivery pump takes place with the aid of a load-displacement diagram, which is derived from the torque curve determined in step d) using the period duration determined in step b) and the im Step c) determined reference phase angle is determined.

This enables the operating properties of the feed pump to be precisely determined in a simple manner.

In a further development of the invention, it is provided that the reference phase angle is determined with respect to the absolute maximum of the power values of the measuring points within a pump cycle.

This enables the operating properties of the feed pump to be precisely determined in a simple manner.

The object according to the invention is also achieved by a pumping system of the type mentioned at the outset, wherein a detection means is also provided which is set up to detect the power consumption of the motor during its operation, and a computing device with a memory is also provided, which is set up to to carry out the method according to the invention with the aid of the detection means.

Fig. 1

ein Ausführungsbeispiel eines erfindungsgemäßen Systems mit einer Gestänge-Tiefpumpe,

Fig. 2

ein Ausführungsbeispiel für einen Pump-Kopf einer Gestänge-Tiefpumpe,

Fig. 3

ein Ausführungsbeispiel für ein Flussdiagramm des erfindungsgemäßen Verfahrens,

Fig. 4

ein erstes Ausführungsbeispiel für ein Last-Weg-Diagramm,

Fig. 5

Last-Weg-Diagramme für eine Pumpe bei verschiedenen Leistungen,

Fig. 6

Last-Weg-Diagramme für eine Pumpe bei verschiedenen Lasten und Betriebsmodi,

Fig. 7

eine zeitliche Darstellung eines Stromverlaufs eines elektrischen Antriebsmotors für eine Gestänge-Tiefpumpe.

The invention is explained in more detail below with reference to an embodiment shown in the accompanying drawings. In the drawings shows

Fig. 1

an embodiment of a system according to the invention with a rod deep pump,

Fig. 2

an embodiment for a pump head of a rod pump,

Fig. 3

an embodiment of a flow chart of the method according to the invention,

Fig. 4

a first embodiment of a load-displacement diagram,

Fig. 5

Load-displacement diagrams for a pump with different capacities,

Fig. 6

Load-displacement diagrams for a pump with different loads and operating modes,

Fig. 7

a temporal representation of a current curve of an electric drive motor for a rod pump.

Fig. 1 shows an embodiment of a pumping system 100 according to the invention with a rod pump 1 of the type of a sucker rod pump.

The pump system 100 comprises a pump head 110 which is connected to a kinematic converter 120 via a linkage 5, 10.

The rod 5, 10 forms a so-called “rod cord” and runs through a borehole head 6, to which a flow line 7 for discharging a conveyed medium 14 is connected.

A jacket 8 adjoins the wellhead 6, in which a tube 9 runs which guides the rods 5 and 10, respectively.

The pump head 110, which contains a piston 11 in a barrel 12, is attached to the lower end of the rod 10. A movement of the piston 11 leads to the pumped medium 14 being pumped out.

The jacket 8 is formed in a borehole 13.

The kinematic converter 120 is driven, for example, by a drive machine in the form of an electric motor 3 via a reduction gear 4. The kinematic converter 120 can additionally include a hydraulic booster.

The mechanical connection of the kinematic converter 120 takes place in this example via a running bar 2, but can vary depending on the type of pump used.

Such kinematic converters are familiar to the person skilled in the art, as is their description in the form of "properties of a kinematic converter" through the transformation function of mechanical movements and forces.

The kinematic converter 120 converts a rotary movement of the motor 3 into a linear movement of the linkage 5, 10.

The properties of the kinematic converter 120 can be described, for example, via leverage and gear ratios, as well as via the electrical drive power and moving masses. It should be noted that the position of a centrifugal mass along a rotary movement and the corresponding force acting on the linkage 10 is related to time, which is referred to as the reference phase angle. A reference phase angle can be determined for a respective pump arrangement using the kinematic principles of mechanics, as is known to the person skilled in the art.

Furthermore, a detection means 110 is provided which is set up to detect the current consumption and the operating voltage of the individual phases of the motor 3 during its operation. This can be done, for example, by an ammeter or voltmeter which, in particular, detects discrete measuring points with current or voltage values with high temporal resolution.

The recorded current and operating voltage values can be used to determine the effective power consumption and the apparent power consumption.

Furthermore, a computing device 140 with a memory 150 is provided, which is set up to carry out the method according to the invention with the aid of the detection means 130.

It is known to the person skilled in the art how a reference phase angle for the kinematic converter 120 using the properties of the kinematic converter 120 and the power consumption 72 of the motor 3, which determines the relationship between the maximum 83 of the power consumption 72 and the maximum of the on the linkage Deep pump 1 describes acting force can be determined.

It is also known to the person skilled in the art how a torque curve can be determined from the power consumption 72 of the motor 3 with the aid of the properties of the kinematic converter 120.

Fig. 2 Figure 11 shows another, more detailed example of a prior art pump head 111.

The rod cord or the linkage 10 is according to the

Fig. 1 driven and set in an up and down linear movement.

In the variant of the pump head 111 shown, a cover tube 15 with vertical grooves is arranged in the borehole 13, which guides a rotating tube 18 with spiral grooves within the cover tube 15 via a holding device 16 and a self-aligning bearing 17.

A receiving tube 19 is connected via a wing nut 20 to a piston assembly 21, which is located in a pump liner 22.

A calibrated rod 23 is connected to the rod 10 via a pin 24 and a holding device 25, which drives the piston arrangement by the linear movement.

1. a) Erfassen der Stromaufnahme und der Betriebsspannung des Motors 3 mit einer Abtastfrequenz über zumindest einen Pumpzyklus, welcher jeweils vier Betriebsphasen der Tiefpumpe 1 zugeordnet werden kann, in Form von diskreten Messpunkten mit Stromwerten, und daraus Bestimmen der Leistungsaufnahme 72 des Motors 3 mit Leistungswerten,
2. b) Bestimmen für einen Pumpzyklus einer Periodendauer 85 und eines Maximums 82 der Leistungsaufnahme 72, welches dem Drehmoment-Maximum der Tiefpumpe 1 entspricht,
3. c) Bestimmen eines Bezugsphasenwinkels für den Kinematik-Wandler 120 mithilfe der Eigenschaften des Kinematik-Wandlers 120 und der Leistungsaufnahme des Motors 3, welcher den Zusammenhang zwischen dem Maximum 82 der Leistungsaufnahme und dem Maximum der auf das Gestänge der Tiefpumpe 1 wirkenden Kraft beschreibt,
4. d) Ermitteln eines Drehmoment-Verlaufs aus der Leistungsaufnahme des Motors 3 mithilfe der Eigenschaften des Kinematik-Wandlers 120,
5. e) Bestimmen der Betriebseigenschaften der Förder-Pumpe 1 aus dem im Schritt d) ermittelten Drehmoment-Verlauf unter Verwendung der im Schritt b) bestimmten Periodendauer und dem im Schritt c) bestimmten Bezugsphasenwinkel.

Fig. 3 shows an exemplary embodiment of a flow chart of the method according to the invention with the following steps:

1. a) recording the current consumption and the operating voltage of the motor 3 with a sampling frequency over at least one pumping cycle, which can each be assigned to four operating phases of the deep pump 1, in the form of discrete measuring points with current values, and from this determining the power consumption 72 of the motor 3 with power values,
2. b) determining for a pumping cycle a period 85 and a maximum 82 of the power consumption 72, which corresponds to the maximum torque of the deep pump 1,
3. c) Determining a reference phase angle for the kinematic converter 120 with the aid of the properties of the kinematic converter 120 and the power consumption of the motor 3, which describes the relationship between the maximum 82 of the power consumption and the maximum of the force acting on the linkage of the deep pump 1,
4. d) determining a torque curve from the power consumption of the motor 3 with the aid of the properties of the kinematic converter 120,
5. e) Determining the operating properties of the feed pump 1 from the torque curve determined in step d) using the period duration determined in step b) and the reference phase angle determined in step c).

The power values can be determined by the product of the discrete current values and the operating voltage.

The period 85 can be determined, for example, with the aid of an approximated polynomial 80 through the power values of the measuring points.

The period 85 can, for example, also be determined with the aid of a polynomial 80 which takes into account statistical mean values of the power values of the respective measuring points over at least five, preferably at least ten, particularly preferably at least fifty pump cycles for support points of the polynomial.

A reference value 81 can be determined for the measuring points, at which for the change in the respective power value between two immediately successive measuring points a maximum is present, and the period 85 is determined with the aid of the reference value 81.

The operating properties of the delivery pump 1 can be determined with the aid of a load-displacement diagram 30, 50, 54, 57, 60-65, which is derived from the torque curve determined in step d) using the period duration determined in step b) and the reference phase angle determined in step c) is determined.

The reference phase angle can be determined with respect to the absolute maximum of the power values of the measuring points within a pump cycle.

FIGS. 4 to 6 show examples of load-displacement diagrams, which are often used to determine the operating characteristics of rod-type deep pumps.

In Fig. 4 a load-displacement diagram 30 is shown.

The position 31 of the polished rod is plotted on the x-axis, and the load 32 of the polished rod is plotted on the y-axis.

A lowest point of the pump stroke 33 and a highest point of the pump stroke 34 can be seen.

Also shown is a tip of the polished rod 35 (PPRI).

A map 36 of the polished rod for a pumping speed equal to zero is shown in dashed lines.

Also, a polished rod map 37 is greater than zero for pumping speed

A minimum load on the polished rod 38 (MPRL) is shown.

A gross piston load 39 can also be read off.

In addition, a weight of the rods in the fluid 40 can be determined, as well as forces 41 and 42, and a pump stroke or pump path 43.

In Fig. 5 Load-displacement diagrams 50 are shown with the rod load at the setpoint value as a function of the load 32 of the polished rod over the respective position 31 of the polished rod.

A load-displacement diagram 51 shows operation at full pump output.

A load-displacement diagram 52 shows operation when the conveying medium has been pumped empty.

A respective nominal value 53 can be seen.

Furthermore, load-displacement diagrams 54 are shown with the rod load in the event of a change in operation as a function of the load 32 of the polished rod over the respective position 31 of the polished rod, with respective angles 55, 56 being readable.

Furthermore, load-displacement diagrams 57 with rod load and the respective mechanical work of the rods are shown.

In Fig. 6 load-displacement diagrams 60-65 are shown for various operating states.

Diagram 60 shows load-displacement diagrams in normal operation.

Diagram 61 shows load-displacement diagrams for a fluid store Diagram 62 shows load-displacement diagrams with exposure to gas in the underground store.

Diagram 63 shows a load-displacement diagram for a stuck piston.

Diagram 64 shows the load-displacement diagram in the event of a leak through a stationary valve.

A diagram 65 shows a load-displacement diagram in the event of a leak through a moving valve.

Fig. 7 shows an example of a time representation of a power curve of an electric drive motor for a rod pump, which was determined from the power consumption and operating voltage of the motor 3.

The illustration has a time axis 70 and an axis 71 for the amplitude of the current or power consumption.

A power consumption 72 is shown for which a zero point or zero axis 80 and a polynomial for averaged power consumption 81 can be determined.

A maximum value of the averaged power consumption 82 and zero crossings of the averaged power consumption 83, 84 can be determined for the polynomial 80.

Furthermore, a period 85 of the averaged power consumption can be determined for the polynomial 80.

From this, a phase angle 86 of the averaged power consumption can be determined, which describes the relationship between the rotary movement of the motor 3 and the linkage 10 of the pump 1.

A corresponding load-displacement diagram can be determined from the determined values in order to derive the operating properties of the rod pump 1 in a simple manner.

List of reference symbols:

1

Rod deep pump

2

Run bar

3

Prime mover, engine

4th

Reduction gear

5

polished rod

6th

Wellhead

7th

Flow line

8th

coat

9

tube

10

Stick cord

11

piston

12th

Run

13th

Borehole

14th

Pumped medium

15th

Cover tube with vertical grooves

16, 25

Holding device

17th

self-aligning bearing

18th

rotating tube with spiral grooves

19th

Pickup tube

20th

Wing nut

21

Piston assembly

22nd

Pump lining

23

calibrated rod

24

pen

30th

Load-displacement diagram

31

Polished rod position

32

Load of the polished rod

33

Lowest point of the pump stroke

34

Highest point of the pump stroke

35

Polished rod tip, PPRI

36

Polished rod map for zero pumping speed

37

Polished rod map for pumping speed greater than zero

38

Polished bar minimum load, MPRL

39

Gross piston load

40

Weight of the rods in the fluid

41, 42

force

43

path

50

Load-displacement diagram with rod load at target value

51

Pump, full power

52

pumped empty

53

Setpoint

54

Load-displacement diagram with rod load when changing operations

55, 56

angle

57

Load-displacement diagram with mechanical work of the rods

60

Load-displacement diagram in normal operation

61

Load-displacement diagram for a fluid bearing

62

Load-displacement diagram with exposure to gas

63

Load-displacement diagram with a stuck piston

64

Load-displacement diagram in the event of a leak through a stationary valve

65

Load-displacement diagram in the event of a leak through a moving valve

70

Timeline

71

Axis for the amplitude of the current or power consumption

72

Power consumption

80

Selected zero point or zero axis

81

Polynomial for averaged power consumption

82

Maximum value of the averaged power consumption

83, 84

Zero crossing of the averaged power consumption

85

Period of the averaged power consumption

86

determined phase angle of the averaged power consumption

100

Pumping system

110, 111

Pump head

120

Kinematic converter

130

Detection means

140

Computing device

150

Storage

Claims (7)

A method for determining the operating properties of a rod pump (1), comprising a pump head (110, 111) which is connected to a kinematic converter (120) via a rod (5, 10), and the kinematic converter ( 120) is driven by an electric motor (3), and furthermore a detection means (130) is provided to detect the power consumption of the motor (3) during its operation, comprising the steps: a) recording the current consumption and the operating voltage of the motor (3) via at least one pumping cycle, to which four operating phases of the deep pump (1) can be assigned, in the form of discrete measuring points, and from this determining the power consumption with power values, b) determining for a pump cycle a period duration (85) and a maximum (82) of the power consumption, which corresponds to the maximum torque of the deep pump (1), c) Determining a reference phase angle for the kinematic converter (120) using the properties of the kinematic converter (120) and the power consumption of the motor (3), which shows the relationship between the maximum (83) of the power consumption and the maximum of the linkage describes the force acting on the pump (1), d) determining a torque curve from the power consumption of the motor (3) with the aid of the properties of the kinematic converter (120), e) Determining the operating properties of the feed pump (1) from the torque curve determined in step d) using the period duration determined in step b) and the reference phase angle determined in step c). Method according to Claim 1, the period duration (85) being determined using an approximated polynomial (80) through the power values of the measuring points. Method according to claim 1, wherein the period duration (85) is determined with the aid of a polynomial (80) which takes into account statistical mean values of the power values of the respective measuring points over at least five, preferably at least ten, particularly preferably at least fifty pump cycles for supporting points of the polynomial. Method according to one of Claims 2 or 3, wherein a reference value (81) is determined for the measuring points, at which a maximum is present for the change in the respective power value between two immediately consecutive measuring points, and the period duration (85) is determined with the aid of the reference value (81 ) is determined. Method according to one of the preceding claims, wherein the determination of the operating properties of the feed pump (1) takes place with the aid of a load-displacement diagram (30, 50, 54, 57, 60-65), which is based on the torque determined in step d) - Course is determined using the period duration determined in step b) and the reference phase angle determined in step c). Method according to one of the preceding claims, wherein the reference phase angle is determined with respect to the absolute maximum of the power values of the measuring points within a pump cycle. Pump system (100) with a rod pump (1), comprising a pump head (110, 111) which is connected to a kinematics converter (120) via a rod (10), and the kinematics converter (120) is driven by an electric motor (3), and furthermore a detection means (110) is provided which is set up to measure the power consumption of the motor (3) during its operation, and furthermore a computing device (140) with a memory (150) is provided, which is set up to carry out the method according to one of the preceding claims with the aid of the detection means (130).

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