OIL FIELD PUMP

Abstract

An oil field pump is installed within a pipe that connects to an oil field, and feeds accumulated extraction oil in a predetermined direction, the oil field pump including a rotor formed with an internal flow path for the extraction oil, a stator mounted on the outer circumference of the rotor, a thrust bearing that supports the axial weight of the rotor and the stator, and a supply pipe that supplies a portion of the extraction oil from the center side in the rotational direction of the flow path to the thrust bearing.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2019-102335 filed in Japan on May 31, 2019.

FIELD

The present invention relates to an oil field pump installed in oil fields.

BACKGROUND

Oil fields extract oil by way of oil field equipment including pipes connecting to positions where oil can be extracted and pumps installed within the pipes to feed the oil within the pipes. The pumps are installed within the fluid in the pipes and feed the oil within the pipes to the oil extraction port. The pumps feed oil extracted from oil fields and the fluid therefore sometimes contains foreign matter. The foreign matter mixes in between rotating parts and stationary parts and causes breakdown if the foreign matter accumulates as deposits.

The technology for example in Patent literature 1 discloses a rotary shaft mechanism including a flow path extending on the circumference of a rotary shaft in sliding contact with the inner circumferential side of a cylindrical-shaped bearing and with at least one end and the other end formed with an opening on the outer circumferential surface of the rotary shaft.

CITATION LIST

Patent Literature

Patent Literature 1: Japanese Patent Application Laid-open No. 2016-130491 A

SUMMARY

Technical Problem

Here, the oil field pump includes a pump body containing an impeller to compress and feed extraction oil, and a motor connecting to the pump body that serves as a drive source. The oil field pump further includes a bearing mechanism. When lubricating oil is supplied to the rotary shaft mechanism, installing supply lines for lubricating oil across the entire area or performing periodic maintenance is needed. In contrast, when lubricating the bearing mechanism with extraction oil, foreign matter might possibly contaminate the bearing mechanism of the oil field pump. The device according to Patent literature 1 can reduce the effect of the foreign matter but requires improvements.

To resolve the aforementioned problems with the related art, the present invention has the objective of providing an oil field pump capable of reducing the need for frequent maintenance.

Solution to Problem

To achieve the above object, an oil field pump installed within a pipe that connects to an oil field, the oil filed pump being configured to feed accumulated extraction oil in a predetermined direction is disclosed. The oil field pump includes a rotor formed with a flow path for the extraction oil therein, a stator mounted on an outer circumference of the rotor, a thrust bearing that supports an axial weight of the rotor and the stator, and a supply pipe that supplies a portion of extraction oil from a center side in a rotational direction of the flow path to the thrust bearing.

It is preferable that the thrust bearing includes a protrusion part fixed to the outer circumference of the rotor and rotating as one piece with the rotor, and a facing part fixed to the stator and facing opposite a surface in an axial direction of the protrusion part, and the extraction oil is filled between the protrusion part and the facing part.

It is preferable that a portion of the supply pipe protrudes into the flow path.

It is preferable that an end of the supply pipe on the flow path side is installed along the flow direction of the extraction oil on the flow path.

It is preferable that the supply pipe is open on an end surface on an inner side of the flow path in a radial direction.

It is preferable that the oil field pump further includes a discharge pipe that discharges the extraction oil supplied to the thrust bearing to further downstream than a connector of the supply pipe of the flow path.

Advantageous Effects of Invention

The present invention is capable of reducing the need for frequent maintenance.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an overall structural view of an oil extraction device including an oil field pump of the embodiment of the present invention.

FIG. 2 is a fragmentary cross sectional view of the oil field pump illustrated in FIG. 1.

FIG. 3 is a cross-sectional view illustrating one example of the mechanism that supplies extraction oil to a thrust bearing.

FIG. 4 is a cross-sectional view illustrating another example of the mechanism that supplies the extraction oil to the thrust bearing.

FIG. 5 is a cross-sectional view taken along line A-A in FIG. 4.

FIG. 6 is an overall structural view illustrating another example of the thrust bearing.

FIG. 7 is an overall structural view illustrating another example of the thrust bearing.

DESCRIPTION OF EMBODIMENTS

The embodiment of the present invention is described next while referring to the drawings. The present invention is not limited by this embodiment. The structural elements in the following embodiment can be easily substituted by one skilled in the art or may include essentially the same item.

FIG. 1 is an overall structural view of an oil extraction device including an oil field pump of the embodiment of the present invention. An oil extraction device 10 is installed on an installation surface 2. The installation surface 2 is a structure installed at an oil field 4. When the oil field 4 is on the ocean floor or in other words, when the oil field 4 is an offshore oil field, the installation surface 2 is a structure at sea level. When the oil field 4 is below ground, the installation surface 2 is a structure at ground level. The oil field 4 is an area to accumulate the oil for extraction.

As illustrated in FIG. 1, the oil extraction device 10 includes a pump (oil field pump) 12, a pipe 14, a ground facility 16, and a guide pipe 18. The pump 12 is equipment that feeds the extraction oil Q accumulated in the oil field 4. The extraction oil Q might contain solid matter such as ores in addition to the crude oil. The pipe 14 is a flow path for the flow of extraction oil therein. One end of the pipe 14 is installed in the oil field 4 and the other end is connected to the ground facility 16. The pump 12 is installed at a section on the oil field 4 side in the pipe 14. The ground facility 16 includes a device to wind up a wire 20 such as a coil turbine or a wire winder mechanism described below. The guide pipe 18 guides the extraction oil.

The pump 12 is described next while referring to FIG. 2 and FIG. 3 in addition to FIG. 1. FIG. 2 is fragmentary cross sectional view of the oil field pump illustrated in FIG. 1. FIG. 3 is a cross-sectional view illustrating one example of the mechanism that supplies the extraction oil to the thrust bearing. The pump 12 includes a wire 20, a pump body 22, a coupler 24, a motor 26, a stationary pipe 28, an electric cable 29, a thrust bearing 50, and a supply pipe 62.

The pump body 22, the coupler 24, and the motor 26 (rotor 30 described below) are integrally connected in the pump 12. The upper end of the pump body 22 connects to the wire 20. The wire 20 can be wound up and fed out by the above described ground facility 16. The stationary pipe 28 fixes a stator 32 that is a portion of the motor 26. The extraction oil Q can flow within the interior of the stationary pipe 28. The electric cable 29 connects between the ground facility 16 and the stator 32 and supplies electrical power to the stator 32.

In the pump 12 of the present embodiment, the pump body 22, the coupler 24, and motor 26, are detachable from the electric cable 29. In other words, winding the wire 20 separates the pump body 22, the coupler 24, and the rotor 30 of the motor 26 as an integrated piece from the stator 32 and raises them upward within the stationary pipe 28. This structure can easily insert and pull up the pump body 22, the coupler 24, and the rotor 30 as an integrated piece so that installing a large scale rig or similar equipment at the installation surface 2 is not necessary.

The motor 26 includes the rotor (rotating part) 30 and the stator (stationary part) 32. The rotor 30 is a cylindrical shape. A flow path 34 for the flow of extraction oil Q therein is formed in the rotor 30. The flow path 34 for the flow of extraction oil Q connects to a flow path of the connecting part 24. In the connecting part 24, flow paths 56, 58 and a branch part 60 are formed as passages for extraction oil Q. The flow path 56 connects to the flow path 34 and the branch part 60. The branch part 60 supplies the extraction oil Q that flows within the rotor 30 to a space between the rotor 20 and the stator 32. The flow path 58 is installed on the upper side perpendicular to the branch part 60, and the internal circumferential surface forms the rotor 30 and the external circumferential surface forms the stator 32. The flow path 58 connects to the flow path of the pump 22.

The rotor 30 can rotate centering on the center axis CL. The rotor 30 includes a permanent magnet 40. The permanent magnet 40 is mounted as one piece with the rotor 30 on the outer circumference of the rotor 30. The stator 32 includes an electromagnet 42. The electromagnet 42 generates a magnetic field from the electrical power supplied from the electric cable 29. The interaction between the magnetic field generated from the electromagnet 40 and the magnetic field generated from the permanent magnet 42 allows rotation of the rotor 30 centering on the center axis CL. An impeller of the pump 22 is mounted on the upper side perpendicular to the rotor 30. Rotation of the rotor 30 rotates the impeller that forms one piece with the rotor 30. The rotation of the impeller compresses and feeds the extraction oil Q on the periphery to the interior of the rotor 30. In other words, the rotor 30 rotates as one piece by the attachment with the rotor (rotating part) of the pump 12. The stator 32 is attached to the stator (stationary part) of the pump 12.

In the coupler 24, the upper end along the central axis of the rotor 30 is inserted into the lower end of the stationary pipe 28. The flow path 56 is connected to the branch part 60 within the stationary pipe 28. The branch part 60 feeds the extraction oil Q flowing upwards perpendicularly within the flow path 34 radially to the outer side R.

The thrust bearing 50 includes a protrusion part 70, a retainer part 72 including a facing part 72a, and a retainer part 74 including a facing part 74a. The protrusion part 70 is fixed to the outer circumference 30a of the rotor 30 and rotates as one piece with the rotor 30. The protrusion part 70 is for example, a disk shape and includes a first surface 70a and a second surface 70b mounted on the front and rear along the axial direction of the center axis CL. In the present embodiment, for example, the first surface 70a is a surface on the lower side in a perpendicular direction, and the second surface 70b is a surface on the upper side in a perpendicular direction. The facing part 72a is the surface opposite the first surface 70a of the protrusion part 70. The facing part 74a is a surface opposite the second surface 70b of the protrusion part 70. The protrusion part 70 includes a cylindrical-shaped side surface 70c centering on the center axis CL. The side surface 70c is a surface opposite an inner circumferential surface 28a of the stationary pipe 28. On the retainer parts 72, 74, the bearing pads 76 are mounted on the surface facing the protrusion part 70. The facing part 72a and the facing part 74a are the front surfaces of the bearing pads 76.

Gaps G filled with lubricating oil are respectively formed between the first surface 70a and the facing part 72a, between the second surface 70b and the facing part 74b, and the side surface 70c and the inner circumferential surface 28a. By filling the extraction oil into the gaps G, the thrust bearing 50 can smoothly rotate the rotor 30, and can support the axial weight on the center axis CL between the rotor 30 and the stator 32. The extraction oil Q extracted from the oil field 4 is utilized as the lubricating oil. The structure for supplying the extraction oil Q to the gap G is described below.

As illustrated from FIG. 1 through FIG. 3, the supply pipe 62 is installed within the flow path 56 and the rotor 30. The supply pipe 62 supplies a portion of the extraction oil Q from the center side in the rotational direction of the flow path 56 to the thrust bearing 50. The supply pipe 62 includes a protrusion pipe 62a protruding into the flow path 56, and a rotor internal pipe 62b formed in the interior of the rotor 30. The protrusion pipe 62a protrudes towards the inner side in the radial direction R from an area bordering the branch part 60 in the rotor 30 and the top end of the protrusion pipe 62a curves downward. The protrusion pipe 62a includes an oil extraction port 62c on the lower end. The oil extraction port 62c is installed on the center side of the radial direction R of the flow path 56. The rotation of the rotor 30 causes a centrifugal force to act on the extraction oil Q flowing within the flow path 56. This centrifugal force causes the solid matter such as ores contained within the extraction oil Q to centrifugally separate to the outer side in the radial direction R in the flow path 56. The extraction oil Q flowing on the outer side in the radial direction R of the flow path 56 therefore has a large solid matter content. The extraction oil Q flowing on the center side in the radial direction R of the flow path 56 has little solid matter content. A solid matter content distribution in this way forms in the radial direction R, between the outer side and the center side in the flow path 56. In the present embodiment, the extraction oil Q can be efficiently collected in a state with little solid matter by installing the oil extraction port 62c on the center side in the radial direction R of the flow path 56.

The oil extraction port 62c faces downward in the perpendicular direction. The protrusion pipe 62a extends upward from the oil extraction port 62c. The end of the supply pipe 62 on the flow path 56 side is installed along the flow direction of the extraction oil Q in the flow path 56. The extraction oil Q flowing from the lower side to the upper side in the perpendicular direction within the flow path 56 can therefore be efficiently collected.

The rotor internal pipe 62b extends along the axial direction of the center axis CL in the interior of the rotor 30. One end of the rotor internal pipe 62b connects to the protrusion pipe 62a. The other end of the rotor internal pipe 62b bends to the outer side in the radial direction R at a position height corresponding to the thrust bearing 50, and connects to the supply port 62d formed on the outer circumferential surface 30a of the rotor 30. The supply port 62d is mounted near the gap G of the thrust bearing 50. The extraction oil Q collected from the oil extraction port 62c flows out from the supply port 62d by way of the protrusion pipe 62a and the rotor internal pipe 62b. A portion of the extraction oil Q flowing out from the supply pipe 62d flows upwards and a portion of the extraction oil Q is supplied to the gap G.

FIG. 4 is a cross-sectional view illustrating another example of the mechanism that supplies the extraction oil Q to the thrust bearing. FIG. 5 is a cross-sectional view taken along line A-A in FIG. 4. As illustrated in FIG. 4, the supply pipe 66 may be configured to collect the extraction oil Q flowing in the flow path 58 on the downstream side (upper side in FIG. 4) of the branch part 60 and supply the extraction oil Q to the thrust bearing 50.

As illustrated in FIG. 4, the supply pipe 66 is formed within the rotor 30. The supply pipe 66 includes an oil extraction port 68a open on the end surface on the inner radial side R of the flow path 58 among the outer circumferential surface 30a of the rotor 30, a supply port 68b formed at a position corresponding to the thrust bearing 50 among the outer circumferential surface 30a of the rotor 30, and a rotor internal pipe 68c that connects with the oil extraction port 68a and the supply port 68b.

The oil extraction port 68a faces the inner circumferential side in the radial direction R of the flow path 58. Rotation of the rotor 30 causes the already described centrifugal force to also act on the extraction oil Q flowing within the flow path 58. This centrifugal force causes the solid matter such as ores contained within the extraction oil Q to centrifugally separate in the outer circumferential side in the radial direction R of the flow path 58. The extraction oil Q flowing on the outer circumferential side in the radial direction R of the flow path 58 therefore has a large solid matter content. The extraction oil Q flowing on the inner circumferential side in the radial direction R of the flow path 58 also has little solid matter content. A solid matter content distribution in this way forms between the outer circumferential side and the inner circumferential side in the radial direction R in the flow path 58. In the present embodiment, the extraction oil Q can be efficiently collected in a state with little solid matter by installing the oil extraction port 68a facing the inner circumferential side in the radial direction R of the flow path 58.

As illustrated in FIG. 5, a plurality of rotor internal pipes 68c are installed around the axial direction of the center axis CL so as to prevent interfering with the branch part 60. Installing the rotor internal pipes 68c at a plurality of locations allows a uniform supply of the extraction oil Q in the rotational direction of the thrust bearing 50.

As illustrated in FIG. 5, a plurality of the branch parts 60 are installed along the axial direction of the center axis CL. Each of the branch parts 60 in the sectional view is formed in a linear shape intersecting in the rotational direction of the rotor 30. Due to centrifugal separation in the flow path 56 within the rotor 30, the solid matter content in the extraction oil Q flowing on the outer side in the radial direction R becomes large. The rotation of the rotor 30 forms a flow along the direction of rotation of the rotor 30 in the flow path 56. In other words, a large amount of solid matter flows along the rotational direction of the rotor 30 on the outer side in the radial direction R. In the example in FIG. 5, a branch part 60 is formed so as to intersect the rotational direction of the rotor 30. Therefore, when the rotor 30 rotates, the inflow of solid matter into the branch part 60 is suppressed. The structure illustrated in FIG. 3 as described above, may be formed so that the branch part 60 intersects the rotational direction of the rotor 30, the same as the structure illustrated in FIG. 5.

As illustrated in the structure in FIG. 5, a discharge pipe 92 is installed within the stationary pipe 28. The discharge pipe 92 includes an inflow port 92a, a discharge port 92b, and a stationary pipe inner pipe 92c. The inflow port 92a is opened at a portion of an area corresponding to the gap G on the inner circumferential surface 28a of the stationary pipe 28. The discharge port 92b is open further downstream (upper side in FIG. 5) than the oil extraction port 68a of the supply pipe 66 among the inner circumferential surface 28a of the stationary pipe 28.

In this structure, among the extraction oil Q flowing from the branch part 60 in the flow path 58, a portion of the extraction oil Q flowing on the inner circumferential side in the radial direction R of the flow path 58, flows into the oil extraction port 68a. The extraction oil Q flowing into the oil extraction port 68a, flows through the connector 68c, and flows out from the supply port 68b. A portion of the extraction oil Q flowing out from a supply port 68d flows upward and a portion of the extraction oil Q flows to the gap G. The extraction oil Q supplied to the gap G is discharged via the discharge pipe 92 to further downstream than the oil extraction port 68a of supply pipe 66 among the flow path 58.

FIG. 6 is an overall structural view illustrating another example of the thrust bearing. As illustrated in FIG. 6, the thrust bearing 50a may be formed in multiple steps along the axial direction of the center axis CL. This structure disperses the load on the thrust bearing 50a in the axial direction along the center axis CL. Therefore, the surface pressure acting on each single thrust bearing 50a is reduced and the gap G can be enlarged. In structures utilizing extraction oil Q containing solid matter as lubricating oil, the bite-in of solid matter among the first surface 70a, the second surface 70b, and the facing parts 72a, 74a of the protrusion part 70 is reduced and a long life can be achieved.

FIG. 7 is an overall structural view illustrating another example of the thrust bearing. As illustrated in FIG. 7, when the thrust bearing 50b is formed in multi-stages along the axial direction of the center axis CL, a spring part 78 may be installed between the protrusion part 70 and at least either of the retainer parts 72, 74. The surface pressure acting on each single thrust bearing 50a can in this way be a uniform surface pressure. The bearing pads 76 may also be installed on the protrusion part 70.

As illustrated in FIG. 6 and FIG. 7, when multi-stage thrust bearings are installed, the supply pipes 62, 66 may be installed at each protrusion part 70 gap, or may be installed so that the extraction oil Q is supplied to the gap of the next protrusion part after passing the gap of one protrusion part.

The pump 12 of the present embodiment in this way serves as an oil field pump installed within a pipe 14 connecting to the oil field 4 that feeds the accumulated extraction oil Q in a predetermined direction, and that includes the rotor 30 formed with a flow path for the extraction oil Q therein, the stator 32 installed on the outer circumference of the rotor 30, the thrust bearing 50 that supports the axial weights on the center axis CL of the rotor 30 and the stator 32, and the supply pipes 62, 66 that supply a portion of the extraction oil Q from the center side in the rotational direction of the flow paths 56, 58 to the thrust bearing 50.

The above described structure forms an area with a large content of solid matter and an area with a small content of solid matter by way of centrifugal separation that is exerted on the extraction oil Q flowing in the flow path, and it is therefore possible to collect the extraction oil Q having a small solid material content. The solid matter content contained within the extraction oil serving as lubricant oil that is supplied to the thrust bearing 50 can therefore be reduced. The need for frequent maintenance can in this way be reduced.

In the pump 12 of the present embodiment, the thrust bearing 50 includes a protrusion part 70 that is fixed to the outer circumference of the rotor 30 and rotates as one piece with the rotor 30, and the facing parts 72a, 74a fixed to the stator 32 and facing opposite the axial direction of the protrusion part, and the extraction oil Q is filled into the gap G between the protrusion part 70 and the facing parts 72a, 74a. Therefore, the extraction oil Q having a small solid material content can be securely supplied to the thrust bearing 50.

In the pump 12 of the present embodiment, a portion of the supply pipe 62 protrudes into the flow path 56. The extraction oil Q flowing in the area near the center side from the radial direction of the flow path 56 can in this way be collected.

In the pump 12 of the present embodiment, the end of the supply pipe 62 on the flow path 56 side is installed along the flow direction of the extraction oil Q in the flow path 56. The extraction oil Q flowing from the lower side to the upper side in the perpendicular direction within the flow path 56 can therefore be efficiently collected.

In the pump 12 of the present embodiment, the supply pipe 66 is open on the end surface on the radial direction side of the flow path 58. The extraction oil Q having small solid matter content can in this way be collected.

The pump 12 of the present embodiment includes a discharge pipe 92 that discharges the extraction oil Q supplied to the thrust bearing 50 to further downstream side than the oil extraction port 68a of the supply pipe 66 of the flow path 58. A flow can in this way be formed for the extraction oil Q supplied to the thrust bearing 50 and therefore new extraction oil Q can be supplied to the thrust bearing 50.

The technical scope of the present invention is not limited to the above embodiment and changes in a range not departing from the spirit and scope of the present invention may be added.

REFERENCE SIGNS LIST

2 Installation surface

4 Oil field

10 Oil extraction device

12 Pump

14 Pipe

16 Ground facility

18 Guide pipe

20 Wire

22 Pump body

24 Coupler

26 Motor

28 Stationary pipe

28a Inner circumferential surface

29 Electric cable

30 Rotor

30a Outer circumference

32 Stator

34, 56, 58 Flow path

40 Electromagnet

42 Permanent magnet

50, 50a, 50b Thrust bearing

60 Branch part

62, 66 Supply pipe

62a Protrusion pipe

62b, 68c Rotor internal pipe

62c, 68a Oil extraction port

62d, 68b, 68d Supply port

68c Connector

70 Protrusion part

70a First surface

70b Second surface

70c Side surface

72, 74 Retainer part

72a, 74a Facing part

78 Spring part

92 Discharge pipe

92a Inflow port

92b Discharge port

92c Stationary pipe inner pipe

CL Center axis

G Gap

Q Extraction oil

R Radial direction

Claims

1. An oil field pump installed within a pipe that connects to an oil field, the oil filed pump being configured to feed accumulated extraction oil in a predetermined direction, the oil field pump comprising:

a rotor formed with a flow path for the extraction oil therein;

a stator mounted on an outer circumference of the rotor;

a thrust bearing that supports an axial weight of the rotor and the stator; and

a supply pipe that supplies a portion of extraction oil from a center side in a rotational direction of the flow path to the thrust bearing.

2. The oil field pump according to claim 1, wherein

the thrust bearing includes a protrusion part fixed to the outer circumference of the rotor and rotating as one piece with the rotor, and a facing part fixed to the stator and facing opposite a surface in an axial direction of the protrusion part, and

the extraction oil is filled between the protrusion part and the facing part.

3. The oil field pump according to claim 1, wherein a portion of the supply pipe protrudes into the flow path.

4. The oil field pump according to claim 3, wherein an end of the supply pipe on the flow path side is installed along the flow direction of the extraction oil on the flow path.

5. The oil field pump according to claim 1, wherein the supply pipe is open on an end surface on an inner side of the flow path in a radial direction.

6. The oil field pump according to claim 5, further comprising a discharge pipe that discharges the extraction oil supplied to the thrust bearing to further downstream than a connector of the supply pipe of the flow path.