JP2022190934A - Lift pump - Google Patents

Abstract

To provide a lift pump that can be operated more stably.SOLUTION: A lift pump comprises a casing having a cylindrical shape along an axis, a pump rotor extending in the direction of the axis, a pump stator surrounding the pump rotor, and a thrust bearing. The pump rotor comprises a plurality of pump shafts, and an impeller for lifting liquid upward by rotating together with the pump shafts. The thrust bearing comprises: a thrust collar attached to an outer peripheral surface of the pump shafts, and comprising a bearing surface; and a thrust pad comprising a pad surface opposed to the thrust collar. A supply flow passage for supplying the liquid pressurized by the impeller to the bearing surface is formed in the pump shafts.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to pumping pumps.

A pump called ESP (Electrical Submersible Pump) has been widely used as a device for pumping up crude oil from an oil well. This type of pump includes a rotating shaft that rotates around the rotating shaft, a plurality of impellers that are integrally provided with the rotating shaft, and a casing that covers the rotating shaft and the impellers from the outer peripheral side. This pump is placed in a pipe inserted into a well (oil field), and a rotating shaft is rotated by an electric motor to pump underground oil upwards.

The rotating shaft is rotatably supported by a plurality of bearing devices with respect to the casing. The bearing device includes a radial bearing that supports radial loads and a thrust bearing that supports axial loads. Among them, a tapered land bearing described in Patent Document 1 below is known as a type of thrust bearing. This type of bearing exhibits bearing performance (load performance) by securing dynamic pressure with a working fluid (crude oil) supplied to the bearing surface.

Japanese Patent Application Laid-Open No. 2006-77803

Here, when a tapered land bearing is applied to the ESP described above, the dynamic pressure on the bearing surface changes due to changes in the viscosity of the crude oil as the moisture content changes, making it impossible to stably maintain the bearing performance. There is As a result, there is a possibility that the stable operation of the apparatus may be affected.

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to provide a pumping pump that can be operated more stably.

In order to solve the above problems, a pumping pump according to the present disclosure includes a tubular casing along an axis extending in the vertical direction, a pump rotor extending in the axial direction within the casing, the casing and the pump rotor. a pump stator surrounding the pump rotor between them; and a thrust bearing rotatably supporting the pump rotor with respect to the pump stator. a shaft, and an impeller that is provided with a plurality of stages on each of these pump shafts and rotates together with the pump shaft to pump liquid upward, and the thrust bearing is attached to the outer peripheral surface of the pump shaft, A thrust collar having an annular shape centered on the axis and having a bearing surface facing the axial direction, and a thrust pad surface provided on the pump stator and facing the thrust collar from both sides in the axial direction. and a pad, wherein the pump shaft is formed with a supply channel for supplying the liquid pressurized by the impeller to the bearing surface.

According to the present disclosure, it is possible to provide a pumping pump that can be operated more stably.

1 is a vertical cross-sectional view showing the configuration of a pumping pump according to an embodiment of the present disclosure; FIG. 1 is an enlarged cross-sectional view of a thrust bearing according to an embodiment of the present disclosure; FIG. FIG. 5 is an enlarged cross-sectional view showing a modification of the thrust bearing according to the embodiment of the present disclosure; FIG. 10 is an enlarged cross-sectional view showing another modification of the thrust bearing according to the embodiment of the present disclosure;

<First embodiment>
(Structure of pumping pump)
A pumping pump according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1 and 2. FIG. A pumping pump 100 according to the present embodiment is a device for pumping up a liquid (crude oil or heavy oil as an example) that has a characteristic that its viscosity changes based on changes in temperature and components. As shown in FIG. 1 , this pumping pump 100 includes a pump body 90 , a motor 80 , a drilling pipe 9 and a thrust bearing 10 . The pump body 90 is driven by power supplied from the motor 80 . The excavation pipe 9 covers the pump main body 90, the motor 80, and the thrust bearing 10 from the outer peripheral side, and has a tubular shape centered on an axis O extending in the vertical direction.

The pump body 90 has a casing body 1 a, a pump rotor 21 and a pump stator 3 . The casing body 1 a is a cylindrical member that is coaxial with the drilling pipe 9 and arranged on the inner peripheral side of the drilling pipe 9 . The pump rotor 21 includes a plurality of pump shafts 21s connected in the direction of the axis O, a coupling sleeve (not shown) connecting the pump shafts 21s, and a plurality of impellers 5 fixed to the pump shafts 21s. have.

Further, on the outer peripheral surface of the pump rotor 21, below the lowermost impeller 5, there is provided an annular thrust collar 10a extending radially outward and centered on the axis O. there is The thrust collar 10 a is supported from above and below by thrust pads 10 b provided on the inner peripheral surface of the pump stator 3 . These thrust collar 10 a and thrust pad 10 b form a thrust bearing 10 . The rotor 2 (the pump rotor 21 and the motor rotor 22 ) is rotatably supported around the axis O with respect to the pump stator 3 by the thrust bearing 10 . A channel (supply channel 21a) extending along the axis O is formed inside the pump shaft 21s. The supply passage 21 a is provided to supply the thrust bearing 10 with crude oil pressurized by the impeller 5 . An upper end portion of the supply flow path 21a communicates with the downstream side (upper side) of the impeller 5 located at the lowest position.

The pump stator 3 has a stator main body 3h that covers the impeller 5 from the outer peripheral side, and a stator extension portion 3e. The stator body 3h accommodates the impeller 5 and defines a stator flow path Fs through which the crude oil flows by repeating expansion and contraction in diameter from bottom to top. The stator extension portion 3e is integrally provided below the stator main body 3h and has a tubular shape centered on the axis O. As shown in FIG.

The motor 80 has a casing tip portion 1b, a motor rotor 22, a coil 81, and a magnetic member 22m. The casing tip portion 1b has a cylindrical shape and is integrally provided below the casing main body 1a. The casing body 1a and the casing tip 1b form a casing 1 (production pipe) as a whole. A plurality of coils 81 arranged in the circumferential direction are provided on the inner peripheral surface of the casing tip portion 1b. This coil 81 generates an electromagnetic force by a current supplied from the outside. The motor rotor 22 is arranged inside the coils 81 and has a columnar shape extending along the axis O. As shown in FIG. The motor rotor 22 is connected to the lowermost pump shaft 21s of the plurality of pump shafts 21s forming the pump rotor 21 via a lower end spline coupling 30d. 21 s of these pump shafts and the motor rotor 22 form the rotor 2 as a whole. A permanent magnet as a magnetic member 22m is provided on the outer peripheral surface of the motor rotor 22 . Rotational force is applied to the rotor 2 by an electromagnetic force generated between the magnetic field generated by energizing the coil 81 and the magnetic field of the magnetic member 22m.

The casing tip portion 1b is supported from below by an annular support portion 4 projecting radially inwardly from the inner peripheral surface of the drilling pipe 9. As shown in FIG. An opening on the inner peripheral side of the support portion 4 is an opening H for taking in the crude oil. The lower end of the motor rotor 22 is inserted through this opening H. Inside the motor rotor 22, in addition to the opening H, a suction passage F for sucking crude oil is formed. The suction flow path F communicates with a stator flow path Fs formed on the inner peripheral side of the pump stator 3 .

(Configuration of thrust bearing)
Next, the configuration of the thrust bearing 10 will be described with reference to FIG. As shown in the figure, the thrust collar 10a of the thrust bearing 10 is fixed to the outer peripheral surface of the pump shaft 21s by interference fit or intermediate fit. The thrust collar 10a has an annular shape centered on the axis O. As shown in FIG. A pair of surfaces facing the direction of the axis O of the thrust collar 10a are used as bearing surfaces 32, respectively. The bearing surface 32 faces the pad surface 31 of the thrust pad 10b with a slight gap in the direction of the axis O. As shown in FIG. That is, a pair of thrust pads 10b are provided so as to face the pair of bearing surfaces 32 from both sides in the direction of the axis O. As shown in FIG.

Although not shown in detail, the thrust bearing 10 is a dynamic pressure bearing and includes a taper land bearing and a tilting pad bearing. Accordingly, grooves are formed in the pad surface 31 of the thrust pad 10b.

The supply flow path 21 a described above is a flow path for guiding the crude oil pressurized by the impeller 5 downward due to the pressure difference across the impeller 5 and then supplying it between the bearing surface 32 and the pad surface 31 . The supply channel 21 a has a main channel 41 and a first discharge channel 42 . The main flow path 41 extends along the axis O inside the pump shaft 21s. The first discharge flow paths 42 extend radially outward from the main flow path 41 and are arranged in plurality at intervals in the circumferential direction. A radially outer end of the first discharge flow path 42 is open between the bearing surface 32 and the pad surface 31 . A pair of first discharge passages 42 are formed at intervals in the direction of the axis O, corresponding to the pair of upper and lower thrust pads 10b.

(Effect)
Next, the operation of the pumping pump 100 will be described. In order to operate the drawing pump 100, the rotor 2 is rotated by first supplying power to the motor 80 described above. When the rotor 2 rotates, the crude oil in the oil well is sucked up by the pump body 90 through the opening H formed at the lower end of the drilling pipe 9 . At this time, the crude oil is also sucked up by the suction passage F formed in the motor rotor 22 . After that, the crude oil flows into the stator flow path Fs and flows upward while being sequentially pressurized by the impeller 5 .

At this time, the thrust bearing 10 is lubricated by the crude oil that has passed through the stator flow path Fs. By the way, when a dynamic pressure bearing is applied as the thrust bearing 10, the dynamic pressure on the bearing surface 32 changes because the viscosity of the crude oil changes as the moisture content changes. Therefore, in some cases, the bearing performance cannot be stably maintained.

Therefore, in the present embodiment, as described above, a configuration is adopted in which the pressurized crude oil is supplied to the thrust bearing 10 through the supply passage 21a. According to the above configuration, static pressure can be generated between the bearing surface 32 and the pad surface 31 by the crude oil supplied through the supply flow path 21a. As a result, static pressure acts on the thrust bearing 10 as a dynamic pressure bearing in addition to the original dynamic pressure, so that the load capacity of the thrust bearing 10 can be improved. Further, even if the dynamic pressure changes, the amount of change can be compensated for by the static pressure, so it is possible to suppress fluctuations in the load capacity.

Furthermore, according to the above configuration, the crude oil can be directly guided between the bearing surface 32 and the thrust pad 10b by the first discharge passage 42. As shown in FIG. Thereby, the static pressure of the bearing surface 32 is further increased, and the load capacity of the thrust bearing 10 can be further improved. Moreover, since the structure is simple, it is possible to suppress increases in manufacturing costs and maintenance costs.

In addition, according to the above configuration, the thrust bearing 10 is a hydrodynamic bearing including a taper land bearing and a tilting pad bearing. As a result, the dynamic pressure inherent in the thrust bearing 10 acts on the bearing surface 32 in addition to the static pressure due to the supply of the crude oil from the supply passage 21a. Thereby, the load capacity of the thrust bearing 10 can be further improved.

Further, according to the above configuration, even when crude oil is used as the liquid to be pumped, the load capacity of the thrust bearing 10 can be ensured. In particular, even if the viscosity of the crude oil drops due to water being mixed with the crude oil, for example, the pressure-increased crude oil is supplied to the bearing surface 32 of the thrust bearing 10 through the supply passage 21a, so that the static pressure is applied to the bearing surface 32. occurs. This makes it possible to improve the performance of the thrust bearing 10 .

The first embodiment of the present disclosure has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure.

<Second embodiment>
Next, a second embodiment of the present disclosure will be described with reference to FIG. In addition, the same code|symbol is attached|subjected about the structure similar to said 1st embodiment, and detailed description is abbreviate|omitted.

As shown in FIG. 3 , the supply channel 21 a according to this embodiment has a main channel 41 , a second discharge channel 43 , an annular channel 44 , and a pad internal channel 45 . The second discharge flow paths 43 extend radially outward from the main flow path 41 and are arranged at intervals in the circumferential direction. Further, the second discharge passages 43 are provided at positions corresponding to the thrust pads 10b in the direction of the axis O. As shown in FIG.

An annular flow path 44 is formed in the inner peripheral surface of the thrust pad 10b. The annular channel 44 is recessed radially outward from the inner peripheral surface of the thrust pad 10b and has an annular shape centered on the axis O. As shown in FIG. The annular flow path 44 communicates with the second discharge flow path 43 described above.

The pad internal flow paths 45 extend radially outward from the annular flow path 44 and are arranged at intervals in the circumferential direction. An opening h that opens onto the pad surface 31 communicates with an intermediate position of the pad internal channel 45 . It is desirable that a plurality of openings h are provided corresponding to the positions of the grooves of the tapered land bearing.

According to the above configuration, the crude oil can be directly guided between the bearing surface 32 and the thrust pad 10b by the pad internal flow path 45 formed inside the thrust pad 10b. Thereby, the static pressure of the bearing surface 32 is further increased, and the load capacity of the thrust bearing 10 can be further improved. In addition, since a plurality of openings h are formed, it is possible to uniformly supply crude oil over the entire bearing surface 32 .

Furthermore, according to the above configuration, the annular channel 44 having an annular shape communicates with the radially extending second discharge channel 43 . Therefore, it is possible to smoothly flow the fluid of the second discharge passage 43 on the rotating side toward the annular passage 44 on the stationary side. This makes it possible to reduce man-hours required for manufacturing and maintenance.

The second embodiment of the present disclosure has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure.

<Third embodiment>
Next, a third embodiment of the present disclosure will be described with reference to FIG. In addition, the same code|symbol is attached|subjected about the structure similar to said each embodiment, and detailed description is abbreviate|omitted.

As shown in FIG. 4, the supply channel 21a according to this embodiment has a main channel 41, a third discharge channel 46, a collar annular channel 47, and a collar internal channel 48. . The third discharge flow paths 46 extend radially outward from the main flow path 41 and are arranged in plurality in a circumferential direction at intervals.

The collar annular channel 47 is formed on the inner peripheral surface of the thrust collar 10a. The collar annular channel 47 is recessed radially outward from the inner peripheral surface of the thrust collar 10a and has an annular shape centered on the axis O. As shown in FIG. The collar annular channel 47 communicates with the third discharge channel 46 described above.

The collar internal flow passage 48 extends radially outward from the collar annular flow passage 47 and is arranged in plurality at intervals in the circumferential direction. An opening h' is formed at an intermediate position of the collar annular channel 47. As shown in FIG. The opening h′ opens onto the bearing surface 32 . It is desirable that a plurality of openings h' be provided corresponding to the number of grooves of the tapered land bearing.

According to the above configuration, the crude oil can be directly guided between the bearing surface 32 and the thrust pad 10b by the collar internal channel 48 formed inside the thrust collar 10a. Thereby, the static pressure of the bearing surface 32 is further increased, and the load capacity of the thrust bearing 10 can be further improved. Moreover, since a plurality of openings h' are formed, it is possible to uniformly supply the crude oil over the entire bearing surface 32 .

Furthermore, according to the above configuration, the collar annular channel 47 having an annular shape communicates with the radially extending third discharge channel 46 . Therefore, when the thrust collar 10a is attached to the pump shaft 21s, it is not necessary to perform circumferential alignment. This makes it possible to reduce man-hours required for manufacturing and maintenance.

The third embodiment of the present disclosure has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure.

For example, in each of the embodiments described above, an example in which the upper end of the supply flow path 21a communicates with the downstream side of the lowermost impeller 5 has been described. However, the upper end of the supply channel 21a may communicate with the downstream side of the impeller 5 further upward (downstream side). This makes it possible to guide crude oil at a higher pressure into the supply channel 21a.

It is also possible to provide the thrust bearings 10 between the impellers 5 depending on the design and specifications. Furthermore, it is also possible to provide a plurality of thrust bearings 10 at intervals in the axis O direction.

In addition, in each of the above embodiments, crude oil was used as an example of the liquid to be pumped. However, the pump 100 can also be suitably used for liquids other than crude oil.

<Appendix>
The pumping pump 100 described in each embodiment is understood as follows, for example.

(1) The pumping pump 100 according to the first aspect includes a tubular casing 1 along an axis O extending in the vertical direction, a pump rotor 21 extending in the direction of the axis O within the casing 1, and the casing 1. A pump stator 3 surrounding the pump rotor 21 between itself and the pump rotor 21, and a thrust bearing 10 rotatably supporting the pump rotor 21 with respect to the pump stator 3. The pump rotor 21 is: A plurality of pump shafts 21s sequentially connected in the direction of the axis O, and an impeller 5 provided with a plurality of stages on each of these pump shafts 21s and pumping liquid upward by rotating together with the pump shafts 21s. , the thrust bearing 10 is attached to the outer peripheral surface of the pump shaft 21s, has an annular shape centered on the axis O, and includes a thrust collar 10a having a bearing surface 32 facing the direction of the axis O; 3, and has a thrust pad 10b having a pad surface 31 facing the thrust collar 10a from both sides in the direction of the axis O, and the pump shaft 21s is provided with the liquid pressurized by the impeller 5. to the bearing surface 32 is formed.

According to the above configuration, static pressure can be generated on the bearing surface 32 by the liquid supplied through the supply channel 21a. Thereby, the load capacity of the thrust bearing 10 can be improved.

(2) In the pumping pump 100 according to the second aspect, the supply flow path 21a includes a main flow path 41 extending in the direction of the axis O inside the pump shaft 21s, and a main flow path 41 extending radially outward from the main flow path 41. It has a plurality of first discharge passages 42 which open between the bearing surface 32 and the thrust pad 10b and which are arranged at intervals in the circumferential direction.

According to the above configuration, the liquid can be directly guided between the bearing surface 32 and the thrust pad 10b by the first discharge flow path 42. As shown in FIG. Thereby, the static pressure of the bearing surface 32 is further increased, and the load capacity of the thrust bearing 10 can be further improved.

(3) In the pumping pump 100 according to the third aspect, the supply flow path 21a includes an annular flow path 44 formed on the inner peripheral surface of the thrust pad 10b and recessed radially outward. A pad internal channel 45 communicating with an annular channel 44 and opening into the pad surface 31, a main channel 41 extending in the axial direction inside the pump shaft, and extending radially outward from the main channel 41 and It has a plurality of second discharge channels 43 that open toward the annular channel 44 and are arranged at intervals in the circumferential direction.

According to the above configuration, the liquid can be directly introduced between the bearing surface 32 and the thrust pad 10b by the pad internal flow path 45 formed inside the thrust pad 10b. Thereby, the static pressure of the bearing surface 32 is further increased, and the load capacity of the thrust bearing 10 can be further improved.

(4) In the pumping pump 100 according to the fourth aspect, the supply flow path 21a is formed in the inner peripheral surface of the thrust collar 10a, and has an annular collar annular flow path 47 that is recessed radially outward; A collar internal channel 48 communicating with the collar annular channel 47 and opening into the bearing surface 32, a main channel 41 extending in the direction of the axis O inside the pump shaft 21s, and a radial direction outside from the main channel 41. a plurality of circumferentially spaced third discharge passages 46 extending toward the collar annular passage 47 and opening toward the collar annular passage 47;

According to the above configuration, the collar internal channel 48 allows liquid to be directly introduced between the bearing surface 32 and the thrust pad 10b. Thereby, the static pressure of the bearing surface 32 is further increased, and the load capacity of the thrust bearing 10 can be further improved.

(5) In the pumping pump 100 according to the fifth aspect, the thrust bearing 10 is a dynamic pressure bearing.

According to the above configuration, the thrust bearing 10 is a hydrodynamic bearing including a taper land bearing and a tilting pad bearing. As a result, the dynamic pressure inherent in the thrust bearing 10 acts on the bearing surface 32 in addition to the static pressure due to the supply of liquid from the supply passage 21a. Thereby, the load capacity of the thrust bearing 10 can be further improved.

(6) In the pumping pump 100 according to the sixth aspect, the liquid has a characteristic that its viscosity changes according to changes in temperature and components.

According to the above configuration, the load capacity of the thrust bearing 10 can be ensured even when, for example, crude oil is used as the liquid. In particular, for example, even if the viscosity of the crude oil is lowered due to water being mixed with the crude oil, static pressure is applied to the bearing surface 32 by supplying the pressurized crude oil to the bearing surface of the thrust bearing 10 through the supply passage 21a. Occur. This makes it possible to improve the performance of the thrust bearing 10 .

100 Pumping pump 1 Casing 1a Casing body 1b Casing tip 2 Rotor 3 Pump stator 3e Stator extension 3h Stator body 4 Supporting part 5 Impeller 9 Drilling pipe 10 Thrust bearing 10a Thrust collar 10b Thrust pad 21 Pump rotor 21a Supply channel 21s Pump Shaft 22m Magnetic member 30d Lower end spline coupling 31 Pad surface 32 Bearing surface 41 Main channel 42 First discharge channel 43 Second discharge channel 44 Annular channel 45 Pad internal channel 46 Third discharge channel 47 Collar annular channel 48 Collar internal channel 80 Motor 81 Coil 90 Pump body F Suction channel h, h' Opening O Axis

Claims (6)

a cylindrical casing along an axis extending in the vertical direction;
a pump rotor extending axially within the casing;
a pump stator surrounding the pump rotor between the casing and the pump rotor;
a thrust bearing that rotatably supports the pump rotor with respect to the pump stator;
with
The pump rotor is
a plurality of pump shafts sequentially connected in the axial direction;
an impeller that is provided with a plurality of stages on each of these pump shafts and rotates together with the pump shaft to pump liquid upward;
has
The thrust bearing is
a thrust collar that is attached to the outer peripheral surface of the pump shaft, has an annular shape centered on the axis, and has a bearing surface facing the axial direction;
a thrust pad provided on the pump stator and having pad surfaces facing the thrust collar from both sides in the axial direction;
has
A pumping pump, wherein the pump shaft is formed with a supply passage for supplying the liquid pressurized by the impeller to the bearing surface. The supply channel is
a main flow path extending in the axial direction within the pump shaft;
a plurality of first discharge passages extending radially outward from the main passage, opening between the bearing surface and the thrust pad, and arranged at intervals in the circumferential direction;
2. The pump of claim 1, comprising: The supply channel is
an annular channel formed in the inner peripheral surface of the thrust pad and recessed radially outward;
a pad internal channel that communicates with the annular channel and opens onto the pad surface;
a main flow path extending in the axial direction within the pump shaft;
a plurality of second discharge passages extending radially outward from the main passage and opening toward the annular passage and arranged at intervals in the circumferential direction;
2. The pump of claim 1, comprising: The supply channel is
an annular collar annular channel formed on the inner peripheral surface of the thrust collar and recessed radially outward;
a collar internal channel communicating with the collar annular channel and opening into the bearing surface;
a main flow path extending in the axial direction within the pump shaft;
a plurality of third discharge channels extending radially outwardly from the main channel and opening toward the collar annular channel and arranged at intervals in the circumferential direction;
2. The pump of claim 1, comprising: The pump according to any one of claims 1 to 4, wherein the thrust bearing is a hydrodynamic bearing. 6. The pump according to any one of claims 1 to 5, wherein the liquid has a property that its viscosity changes based on changes in temperature/components.

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