EP2865894A1 - Submersible pump unit for use in a borehole - Google Patents

Abstract

The invention relates to a submersible pump unit for use in a borehole, comprising a screw pump and / or an eccentric screw pump with a longitudinal axis. The dipping unit further comprises a drive and a bearing arrangement for receiving and discharging the axial and / or radial forces occurring during operation of the worm pump and / or eccentric worm pump. The drive is arranged via a first coupling rod at one end of the screw pump and / or eccentric screw pump and the bearing assembly is associated with the opposite end of the screw pump and / or eccentric screw along the longitudinal axis via a second coupling rod.

Description

The present invention relates to a submersible pump unit for use in a well according to the features of the preamble of claim 1.

State of the art

Submersible pumps for use in a borehole are known from the prior art, for example as NSPCP (Netzsch submersible PCP = submersible screw pump from Netzsch) or ESPCP (= electric submersible screw pump). In these submersible pumps, a submersible motor located at the lower end is provided, which drives an eccentric screw pump located above by means of a coupling rod. The use of eccentric screw pumps has the advantage over the conventionally used centrifugal pumps that products with higher viscosity, for example, with higher sand and Paraphinanteilen can be promoted.

In order to be able to absorb the axial force resulting from the delivery pressure, a bearing arrangement for mounting the coupling rod is usually arranged directly above the submersible motor or above a transmission unit connected to the submersible motor.

DE 10258666 A1 describes a submersible pump device for use in a wellbore with a worm or eccentric screw, wherein between the slowly rotating drive and the worm or eccentric screw pump, an axially and radially force-absorbing coupling member is arranged.

DE 19848792 C1 describes a submersible pump device for use in a borehole, which comprises a gear and a compensator between the drive and the eccentric screw pump. A gear stage is used to slow down the rotational movement of the input shaft in the transmission housing. The compensator equalizes the lubrication fluid pressure in the transmission housing to the ambient pressure. To the resulting Distribute heat of the gear stage evenly on the lubricating fluid, the compensator is disposed within the gear housing next to the gear stage and integrated into the lubricating fluid circuit.

A major disadvantage of these arrangements is that slender and fast-running coupling rods tend to buckle between the drive and screw or eccentric screw due to the prevailing axial force and then start on the housing tube. This leads to friction between coupling rod and housing tube and thus wear of these components, which must be replaced or replaced accordingly frequently.

The object of the invention is to eliminate the disadvantages of the prior art, in particular a buckling of the coupling rods is to be prevented due to acting on the coupling rods axial forces.

The above object is achieved by a submersible pump unit comprising the features in claim 1. Further advantageous embodiments are described by the subclaims.

description

The invention relates to a submersible pump unit for use in a borehole. In particular, drill hole is a hole in the ground in order to promote oil and natural gas to understand. In particular, the submersible pump unit comprises a screw pump and / or an eccentric screw pump with a longitudinal axis for conveying medium within a riser arranged in the borehole in an upwardly directed conveying direction, that is to say in a conveying direction directed towards the earth's surface. The screw pump and / or eccentric screw pump is preferably driven by a drive, in particular a motor. The submersible pump assembly further includes a bearing assembly. The bearing assembly serves to receive and derive the occurring during operation of the screw pump and / or eccentric screw axial and / or radial forces.

According to the invention, the drive via a first coupling rod at one end of the screw pump and / or eccentric screw pump along the longitudinal axis arranged. The bearing assembly is associated with the opposite end of the screw pump and / or eccentric screw along the longitudinal axis via a second coupling rod. In particular, the bearing arrangement is thus assigned to the end of the rotor of the worm pump and / or eccentric worm pump facing away from the drive.

In an arrangement of the submersible pump unit in the borehole, the drive is preferably arranged below the screw pump and / or eccentric screw pump. In particular, a first coupling rod is arranged between the drive and the rotor of the screw pump and / or eccentric screw pump, which transmits the drive energy to the rotor. The bearing arrangement of the submersible pump unit is arranged within the borehole above the screw pump and / or eccentric screw pump.

According to one embodiment of the invention is used as a bearing assembly an employed support bearing in O-form. This can absorb both axial and radial forces and divert into the surrounding structure, wherein the function of receiving axial and radial forces is divided into a thrust bearing and a radial bearing. In the employed support bearing, the two bearings are braced against each other and there is only a slight tilting play.

According to one embodiment of the invention, the bearing arrangement is part of a storage unit. The screw pump and / or eccentric screw pump has a rotor and a stator, wherein a first coupling rod for transmitting the drive energy of the drive is arranged on the rotor between the drive arranged in the downhole and the rotor arranged above the screw pump and / or eccentric screw. Furthermore, a second coupling rod is arranged between the end of the rotor facing away from the drive and the bearing unit.

Preferably, the bearing unit is connected via a fastening device with the second coupling rod and / or with a housing tube surrounding the second coupling rod. Furthermore, in a region between the fastening device and the bearing arrangement, the bearing unit may comprise a mechanical seal for sealing the interior of the bearing unit. In particular, the sliding ring direction hermetically seals the bearing interior at the lower end of the bearing unit with respect to the conveyed medium.

According to one embodiment of the invention, the storage unit is flowed around in the well of funded medium, whereby heat of the bearing assembly is discharged.

The bearing unit may further comprise a pressure compensating piston for equalizing the differential pressure between a lubricant of the bearing assembly and the conveyed medium. The pressure balance piston prevents the oil-lubricated bearing unit from being contaminated by contaminated fluid by compensating for the differential pressure between the bearing unit lubricating oil and the pumped fluid.

In the submersible pump unit according to the invention, the axial and / or radial forces of the screw pump and / or eccentric screw pump are converted by the bearing unit into a tensile force. Instead of supporting the axial force as a compressive force on a bearing arrangement located under the eccentric screw pump, between eccentric screw pump and submersible motor - as conventionally known - this is intercepted in the submersible pump unit according to the invention as a pulling force on a bearing arrangement of the bearing unit located above the screw pump and / or eccentric screw pump and in the flow , The bearing unit thus serves in particular to protect the coupling rods, since they are relieved of the buckling force.

figure description

• Figur 1 zeigt ein erfindungsgemäßes Tauchpumpenaggregat mit Lagereinheit zur Verwendung in einem Bohrloch.
• Figur 2 zeigt eine Lagereinheit eines Tauchpumpenaggregats gemäß Figur 1.

In the following, embodiments of the invention and their advantages with reference to the accompanying figures will be explained in more detail. The proportions of the individual elements to one another in the figures do not always correspond to the actual size ratios, since some shapes are simplified and other shapes are shown enlarged in relation to other elements for better illustration.

• FIG. 1 shows a submersible pump unit according to the invention with storage unit for use in a borehole.
• FIG. 2 shows a storage unit of a submersible pump unit according to FIG. 1 ,

For identical or equivalent elements of the invention, identical reference numerals are used. Furthermore, for the sake of clarity only reference numerals in the individual figures that are required for the description of the respective figure. The illustrated embodiments are only examples of how the device according to the invention can be designed and do not represent a final limitation.

FIG. 1 shows a submersible pump unit 1 with bearing unit 10 for use in a borehole BL. In the borehole BL, a lining 30 is often provided which stabilizes the borehole BL. The submersible pump unit 1 comprises an eccentric screw pump 3 with a longitudinal axis L, a drive 2, for example a motor M for driving the eccentric screw pump 3, and a bearing assembly 12 for receiving and discharging the axial and / or radial forces occurring during operation of the eccentric screw pump 3.

The submersible pump unit 1 is arranged in particular in the borehole BL such that the drive 2 forms the lower end of the submersible pump assembly 1. Above the submersible pump unit 1, a riser SR is arranged, in which the liquid flow FS of the pumped medium rises in the conveying direction FR upwards.

The eccentric screw pump 3 comprises a pump housing 4 with suction openings 5 for the medium to be conveyed in the conveying direction FR. Furthermore, the eccentric screw pump 3 comprises a stator 7 and a rotor 6. The rotor 6 is connected via a directly driven, arranged in the pump housing 4 coupling rod 8 with the external drive 2. The opposite end of the rotor 6 is connected to the bearing unit 10 via a further coupling rod 9, which is surrounded by a housing tube 20. In particular, the bearing unit 10 thus forms within the borehole BL the upper end of the submersible pump unit 1 and directly adjoins the riser SR.

The upper coupling rod 9 is bathed within the housing tube 20 by the liquid flow FS of the pumped medium. At the upper end of the coupling rod 9, which is opposite to the rotor 6, the bearing unit 10 is arranged, which in FIG. 2 is shown in detail. In particular, a fastening device 40 is provided, which connects the housing tube 20 with the bearing unit 10.

FIG. 2 shows a storage unit 10 of a submersible pump unit 1 according to FIG. 1 , The bearing unit 10 serves in particular to guide the upper coupling rod 9 and to initiate the operation of the eccentric screw pump 3 (cf. FIG. 1 ) occurring axial forces in the surrounding structure. The bearing unit 10 comprises a bearing housing 11 with a bearing arrangement 12 arranged therein. The bearing arrangement 12 effects an axial and radial force-absorbing coupling, which is necessary for the safe operation of the eccentric screw pump 3.

This may be, for example, a so-called fixed bearing that can absorb both axial and radial forces and in the surrounding structure, in particular in the bearing housing 11, can derive. Alternatively, a so-called separate bearing arrangement can be used, in which the function recording axial and radial forces is divided into a thrust bearing and a radial bearing. In the embodiment shown, a so-called employed support bearing 13 is used as a bearing assembly 12. By employing thrust bearings and radial bearings is meant a defined bracing of the two bearings against each other. In the illustrated O-arrangement, the bearing arrangement 12, 13 can accommodate a greater tilting moment than in an X-arrangement (not shown), since in the O-arrangement the distance of the pressure centers is greater.

The upper free end of the bearing unit 10 is arranged and fixed at the lower end of a riser SR. Between bearing assembly 12 and riser SR a pressure compensation piston 15 is provided. With the pressure equalizing piston 15, the differential pressure between the lubricating oil of the bearing assembly 12 and the conveyed medium is compensated. This effectively prevents the oil-lubricated bearing unit 10 is contaminated by contaminated fluid.

At the shaft input, that is adjacent to the upper end of the coupling rod 9 and at the lower end or in the lower region of the bearing unit 10, a slide ring 16 is arranged. The mechanical seal 16 hermetically seals the interior of the bearing unit 10 to the flow FS of the pumped medium. The storage unit 10 is flowed around by conveying medium, whereby the heat of the bearing assembly 12 of the storage unit 10 is discharged.

Instead of the axial force - as conventional - known as compressive force on one under the eccentric screw 3, between eccentric screw 3 and submersible motor M, support bearing arrangement, the axial force is trapped as a tensile force on a located above the eccentric screw 3 and the liquid flow FS bearing unit 10 and thus the underlying coupling rods 8, 9 relieved of the buckling force.

The invention has been described with reference to a preferred embodiment. However, it will be apparent to those skilled in the art that modifications or changes may be made to the invention without departing from the scope of the following claims.

LIST OF REFERENCE NUMBERS

1

A submersible pump unit

2

drive

3

Cavity Pump

4

pump housing

5

suction

6

rotor

7

stator

8th

coupling rod

9

coupling rod

10

storage unit

11

bearing housing

12

bearing arrangement

13

hired support bearing

15

Balance piston

16

Mechanical seal

20

housing tube

30

lining

40

fastening device

BL

well

FR

conveying direction

FS

flow

L

longitudinal axis

M

engine

SR

riser

Claims (10)

Submersible pump unit (1) for use in a borehole (BL), comprising a screw pump and / or an eccentric screw pump (3) with a longitudinal axis (L), a drive (2) and a bearing arrangement (12) for receiving. and deriving the axial and / or radial forces which occur during operation of the screw pump and / or eccentric screw pump (3), characterized in that the drive via a first coupling rod (8) at one end of the screw pump and / or eccentric screw pump (3) along the longitudinal axis ( L) is arranged and that the bearing assembly (12) via a second coupling rod (9) is associated with the opposite end of the screw pump and / or eccentric screw pump (3) along the longitudinal axis (L). Submersible pump unit (1) according to claim 1, wherein the submersible pump unit (1) is arranged in the borehole (BL), that the drive (2) in the borehole (BL) below the screw pump and / or eccentric screw pump (3) is arranged and that the bearing assembly (12) of the submersible pump unit (1) within the borehole (BL) above the screw pump and / or eccentric screw pump (3) is arranged. Submersible pump unit (1) according to claim 1 or 2, wherein the bearing assembly (12) is an employed support bearing (13) in O-shape. Submersible pump unit (1) according to one of the preceding claims, wherein the bearing arrangement (12) is part of a bearing unit (10). Submersible pump unit (1) according to claim 4, wherein the screw pump and / or eccentric screw pump (3) has a rotor (6) and a stator (7), wherein between the drive (2) and the rotor (6) of the screw pump and / or eccentric screw pump (3) a first coupling rod (8) for transmitting the drive energy of the drive (2) is arranged on the rotor (6), wherein between the drive (2) facing away from the end of the rotor (6) of the screw pump and / or eccentric screw pump (3 ) and the bearing unit (10) a second coupling rod (9) is arranged. Submersible pump unit (1) according to claim 5, wherein the bearing unit (10) via a fastening device (40) with the second coupling rod (9) and / or with a second coupling rod (9) surrounding the housing tube (20). Submersible pump unit (1) according to claim 6, wherein the bearing unit (3) in a region between the fastening device (40) and the bearing assembly (12) comprises a mechanical seal (16) for sealing the interior of the bearing unit (10). Submersible pump unit (1) according to one of claims 4 to 7, wherein the bearing unit (3) in the borehole (BL) flows around of conveyed medium, whereby heat of the bearing assembly (12) can be discharged. Submersible pump unit (1) according to one of claims 4 to 8, wherein the bearing unit (3) comprises a pressure compensating piston (15) for compensating the differential pressure between a lubricant of the bearing assembly (12) and the conveyed medium. Submersible pump unit (1) according to one of claims 4 to 9, wherein the axial force of the screw pump and / or eccentric screw pump (3) by the bearing assembly (12) of the bearing unit (10) is convertible into a tensile force.

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