RU2810186C1 - Method of operation of submersible multi-stage centrifugal pump with polymer impellers and design for its implementation - Google Patents

Abstract

FIELD: petroleum engineering.

SUBSTANCE: group of inventions relates to multi-stage submersible pumps for pumping formation fluid from wells. The method of operation of the installation of a submersible multi-stage centrifugal pump is to lift the formation fluid in steps containing a guide vane and an impeller made of materials that cannot come into contact with each other during operation. Axial supports are installed between the guide vane and the impeller, which include support washers. A sealing sleeve is installed on the shaft for each stage, eliminating leakage, made of a material that can be in friction pair with the material from which the mating surface of the guide vane is made. The impeller is made of a polymer material with a low rate of salt deposition, low weight, smooth surface of the flow part, and high corrosion resistance. There is a gap between the wheel hub and the guide vane hub, the size of which is guaranteed to exclude contact between the impeller and the guide vane during operation. A blade rim is made on the driving disk of the impeller, which provides the optimal amount of axial force acting on the impeller. The installation of a submersible multistage centrifugal pump contains a motor, hydraulic protection, a pump containing a shaft, one stage containing a guide vane consisting of a shell, a lower disk with a hub, an upper disk, with blades installed between the disks, an impeller that contains a drive disk with a hub and a covering disk, with blades installed between the disks. Between the upper disk of the guide vane and the driven disk of the impeller, between the hub of the guide vane and the driving disk of the impeller, axial supports are installed, which include support washers. A sealing sleeve is installed on the shaft for each stage, the length of which is at least fifty percent of the length of the guide vane hub. The impeller is made of a polymer thermoplastic material; a gap is made between the wheel hub and the guide vane hub, the value of which is twenty percent greater than the gap between the sealing sleeve and the guide vane hub. A blade rim is made on the driving disk of the impeller, the height of the blade rim does not exceed the minimum distance between the driving and covering disks of the impeller, the angle between each blade of the blade rim at its periphery and the radius is from minus 30° up to plus 30°.

EFFECT: increase in the efficiency and reliability of the centrifugal pump installation.

11 cl, 7 dwg

Description

The group of inventions relates to petroleum engineering, in particular to multi-stage submersible pumps for pumping formation fluid from wells.

Known from patent RU 2449176 is a method of operating a submersible multistage centrifugal pump, in which the impeller is made of solid cast iron and contains impellers - blade rims.

The disadvantage of the stage is its high cost due to the need to introduce expensive additives into the material from which the stage is made in order to reduce the coefficient of friction. Also, the impellers and, consequently, the pump rotor have a relatively large weight, imbalance and vibration, which reduces the service life. Relatively high roughness reduces hydraulic efficiency and the efficiency of the installation.

The closest analogue is the method of operation of a submersible multistage centrifugal pump from patent RU 2564742. When the impeller rotates, due to the presence of a blade rim on the drive disk, the liquid in the bosom between this disk and the guide vane rotates at a higher angular speed than in the absence of a blade rim. A torus-shaped vortex appears, due to which the fluid transfers from the impeller to the guide vane. With the help of a helical groove on the inner diameter of the guide vane shell, mechanical impurities are effectively transferred with the fluid flow from one stage to the entrance to the guide vane of the next stage. Free gas present in the liquid flow is dispersed by the blade ring. Mechanical impurities are washed out of the friction pair through radial grooves made on the support washers.

The disadvantage is that cast iron impellers are heavy, susceptible to corrosion, and have a rough surface of the flow part. The size of the gap between the hubs of the apparatus and the wheel has not been determined, ensuring the absence of guaranteed contact during long-term operation of the pump in the well. Therefore, relatively high rotor vibration occurs, low service life and efficiency.

Known from patent RU 2449176 is the stage of a submersible multistage centrifugal pump, the impeller of which is made of solid cast iron and contains impellers - blade rims.

The disadvantage of the stage is its high cost due to the need to introduce expensive additives into the material from which the stage is made in order to reduce the coefficient of friction.

The closest analogue is a submersible multistage centrifugal pump from patent RU 2564742, which includes a shaft, at least one stage containing a guide device made in the form of a solid cast iron structure, consisting of a shell, a lower disk with a hub, an upper disk, blades are made between the disks, an impeller made in the form of a solid cast iron structure, which contains a drive disk with a hub and a cover disk, blades are placed between the disks, and between the upper guide disk and the driven disk of the impeller, between the guide vane hub and the drive disk of the impeller wheels, axial supports are installed, which include support washers, in accordance with the invention, a sealing sleeve is installed on the shaft for each stage, the length of which is at least fifty percent of the length of the guide vane hub, on the inner diameter of the guide vane hub, on the side of the impeller hub is made a groove whose diameter is obviously larger than the outer diameter of the impeller hub.

The disadvantage is that cast iron impellers are heavy, susceptible to corrosion, and have a rough surface of the flow part. The size of the gap between the hubs of the apparatus and the wheel has not been determined, ensuring the absence of guaranteed contact during long-term operation of the pump in the well. Therefore, high rotor vibration, low service life and efficiency are possible.

The technical problem of the group of claimed inventions is the creation of a technical solution that significantly reduces the weight, imbalance and vibration of the rotor, establishes a gap between the hubs of the guide vane and the impeller, which is guaranteed to exclude contact of parts during long-term operation of the installation, increases the smoothness of the surface of the flow part, and ensures corrosion resistance , the rate of salt deposition is reduced due to the use of polymer material.

The technical result of the group of inventions is to increase the efficiency and reliability of the centrifugal pump installation.

The technical problem is solved by the fact that the method of operation of the installation of a submersible multistage centrifugal pump consists in lifting the reservoir fluid in steps containing a guide vane and an impeller made of materials that cannot come into contact with each other during operation; axial drives are installed between the guide vane and the impeller supports, which include support washers; a sealing sleeve is installed on the shaft for each stage, eliminating leakage, made of a material capable of being in a friction pair with the material from which the mating surface of the guide vane is made, while the impeller is made of a polymer material, with a low rate of salt deposition, low weight, smooth surface of the flow part, with high corrosion resistance, a gap is made between the wheel hub and the hub of the guide vane, the size of which is guaranteed to exclude contact of the impeller and the guide vane during operation, A blade rim is made on the driving disk of the impeller, which provides the optimal amount of axial force acting on the impeller.

The inventive method has the following implementation aspect.

Structural elements are made on the inner diameter of the guide vane shell and on the outer diameter of the sealing sleeve to remove mechanical impurities and disperse large bubbles of free gas.

The stated technical result is also achieved due to the fact that in the installation of a submersible multistage centrifugal pump, which includes an engine, hydraulic protection, a pump containing a shaft, one stage containing a guide apparatus consisting of a shell, a lower disk with a hub, an upper disk, between blades are made of disks, an impeller, which contains a drive disk with a hub and a covering disk, blades are placed between the disks, and between the upper disk of the guide vane and the driven disk of the impeller, between the hub of the guide vane and the drive disk of the impeller, axial supports are installed, which include support washers are included, a sealing sleeve is installed on the shaft for each stage, the length of which is at least fifty percent of the length of the guide vane hub, the impeller is made of polymer thermoplastic material, a gap is made between the wheel hub and the guide vane hub, the value of which is twenty percent greater , the size of the gap between the sealing sleeve and the guide vane hub, a blade rim is made on the driving disk of the impeller, the height of the blade rim does not exceed the minimum distance between the driving and covering disks of the impeller, the angle between each blade of the blade rim at its periphery and the radius is from minus 30 ° up to plus 30°.

The inventive submersible installation has the following implementation aspects.

There are roundings made between the side faces of each blade of the blade rim and the drive disk; the radius of the roundings is from 0.1 to 0.8 of the height of the blade rim.

The pump shaft rests on the engine hydraulic protection shaft.

A groove is made on the inner diameter of the guide vane hub on the impeller hub side.

A helical groove is made on the inner diameter of the guide vane shell.

A helical groove is made on the outer diameter of the sealing sleeve.

The guide vane hub is made of polymer material.

The guide apparatus is made of cast iron, which contains, in particular, silicon, manganese, chromium, cerium, phosphorus and sulfur, with the following content of these elements, wt. %:

carbon 3.5-3.9 silicon 2.1-2.7 manganese 0.4-0.6 phosphorus <0.3 cerium <0.03 boron <0.01 sulfur <0.05 chromium <0.12 iron rest

The guide apparatus is made of cast iron, which contains, in particular, silicon, manganese, chromium, nickel, copper, phosphorus and sulfur, with the following content of these elements, wt. %:

carbon <3 silicon 1.0-2.8 manganese 0.5-1.5 nickel 13.5-17.5 copper 5.0-8.0 chromium 1.5-2.5 aluminum <0.3 sulfur <0.05 phosphorus <0.25 iron rest

The essence of technical solutions is explained as follows.

If the impeller is made of a polymer material, for example, polyphenylene sulfide with a low density, five times less than cast iron, a smooth surface of the flow part, with high corrosion resistance, then the weight, imbalance, and vibration of the rotor are significantly reduced. The rate of deposition of salts and mechanical impurities is reduced.

If a gap is made between the wheel hub and the guide vane hub, the value of which is twenty percent greater than the gap between the sealing sleeve and the guide vane hub, contact between the impeller and the guide vane during operation is guaranteed to be eliminated, and the reliability of the installation increases.

The length of the sealing sleeve is at least fifty percent of the length of the guide vane hub. In this case, as the results of physical and numerical experiments show, the sealing sleeve can not only effectively reduce fluid leakage, but also work reliably as an intermediate bearing. With a shorter length, the volumetric efficiency decreases due to leaks, and the service life decreases due to an increase in the specific load on the friction pair.

If a blade rim is made on the driving disk of the impeller, the height of which does not exceed the minimum distance between the driving and covering disks of the impeller, the angle between each blade of the blade rim at its periphery and the radius ranges from minus 30° to plus 30°.

This design provides the optimal value of the axial force acting on the impeller.

If the angle is greater or less than the specified one, as shown by the results of physical and numerical experiments, the flow will spin worse in the area between the driving disk of the impeller and the lower disk of the guide vane, while hydraulic losses will increase, and due to this, the efficiency of the stage will decrease.

If roundings (fillets) are made between the side edges of each blade of the blade rim and the drive disk, the radius of the fillets is from 0.1 to 0.8 of the height of the blade rim, the hydraulic efficiency of the stage increases.

With a smaller fillet radius, as shown by the results of physical and numerical experiments, stagnant areas arise, leading to an increase in hydraulic losses of vortex formation. With an increase, the flow in the area between the driving disk of the impeller and the lower disk of the guide vane becomes worse, hydraulic losses increase and, as a result, the efficiency of the stage decreases.

If the pump shaft rests on the hydraulic motor protection shaft, which has an axial support in oil, then the reliability of the installation will increase compared to design options in which the engine rests on impellers or on an axial support operating in the formation fluid.

If a groove is made on the inner diameter of the guide vane hub, on the side of the impeller hub, this will increase the radial clearance between the hubs of the impeller and the guide vane, eliminating the possibility of their contact during long-term operation of the unit in the well.

If a helical groove is made on the inner diameter of the guide vane shell, this will make it possible to better remove mechanical impurities and disperse free gas bubbles. This solution is especially relevant in the case of manufacturing the guide vane from a polymer material.

If a screw groove is made on the outer diameter of the sealing sleeve, this will allow mechanical impurities to be removed and better cooling of the friction pair. This solution is especially relevant in the case of manufacturing the guide vane from a polymer material.

If the guide vane hub is made of a polymer material, this will reduce the likelihood of salt deposits and jamming of the pump rotor shaft.

If the guide devices are made of cast iron, which contains silicon, manganese, chromium, cerium, phosphorus and sulfur, with the following content of these elements, wt. %:

carbon 3.5-3.9 silicon 2.1-2.7 manganese 0.4-0.6 phosphorus <0.3 cerium <0.03 boron <0.01 sulfur <0.05 chromium <0.12 iron rest

Installations with such working bodies are low cost and can be used in wells that do not require corrosion-resistant equipment.

If the guide devices are made of cast iron, which contains silicon, manganese, chromium, nickel, copper, phosphorus and sulfur, with the following content of these elements, wt. %:

carbon <3 silicon 1.0-2.8 manganese 0.5-1.5 nickel 13.5-17.5 copper 5.0-8.0 chromium 1.5-2.5 aluminum <0.3 sulfur <0.05 phosphorus <0.25 iron rest

Installations with such working bodies can be used in wells that do not require corrosion-resistant equipment.

The essence of the invention is illustrated by figures 1-7, which show:

fig. 1 - diagram of a submersible installation consisting of an engine, hydraulic protection, gas separator, pump and tubing;

fig. 2 - general cross-sectional view of the pump;

fig. 3 - sectional assembly of stages with polymer impellers;

fig. 4 - guide vane with a helical groove made on the inner diameter of the shell and a sectional groove on the hub;

fig. 5 - sealing sleeve with a screw groove;

fig. 6 - axial support with ribs;

fig. 7 - view of the section of the scapular rim with blades.

In fig. 1-7 positions 1-30 indicate:

1. electric motor;

2. water protection;

3. gas separator;

4. vane pump;

5. tubing;

6. guide vane;

7. body;

8. impeller;

9. shaft;

10. bearing;

11. sealing sleeve;

12. driving disk of the impeller;

13. driven disk of the impeller;

14. impeller hub;

15. impeller blades;

16. lower disk of the guide vane;

17. upper disk of the guide vane;

18. guide vanes;

19. guide vane hub;

20. additional blade crown;

21. groove in the guide vane hub;

22. guide vane shell;

23. helical groove in the shell of the guide vane;

24. screw groove on the sealing sleeve;

25. pump section base;

26. pump section head;

27. axial supports in the form of ribs;

28. impeller support washers;

29. the angle between the blade of the blade rim at its periphery and the radius;

30. roundings between the side edges of the blade rim and the drive disk.

The submersible installation contains an electric motor 1, a hydraulic protection 2, a gas separator 3, a vane pump 4, and tubing pipes 5.

Vane pump 4 contains guide vanes 6 installed in housing 7, impellers 8 mounted on shaft 9.

Bearings 10 are installed between the housing 7 and the shaft 9.

A sealing sleeve 11 is installed on the shaft 9 inside the guide vane 6.

The impeller 8 contains a drive disk 12, a driven disk 13, a hub 14, and blades 15 are installed between the disks. The guide vane 6 contains a lower disk 16, an upper disk 17, blades 18, and a hub 19.

Between the hub 14 of the impeller 8 and the hub 19 of the guide vane 6, a gap is made, the value of which is twenty percent greater than the gap between the sealing sleeve 11 and the hub 19 of the guide vane.

On the drive disk 12 of the impeller 8, a blade rim with blades 20 is made.

The height of the blade rim 20 does not exceed the minimum distance between the driving 12 and the driven (cover) 13 disks of the impeller, the angle 29 between each blade of the blade rim 20 at its periphery and the radius ranges from minus 30° to plus 30°

Between the side edges of each blade of the blade rim 20 and the drive disk 12, roundings 30 are made; the radius of the roundings is from 0.1 to 0.8 of the height of the blade rim 20 at the point of rounding 30.

The wheel has axial support washers 28.

As an axial support during ascent, radial ribs (axial supports in the form of ribs) 27 are made on the drive disk 12 of the impeller 8, which operate as a hydrodynamic bearing.

In the hub 19 of the guide vane 6, a groove 21 is made.

A helical groove 23 is made on the inner diameter of the shell 22 of the guide vane 6.

A helical groove 24 is made on the outer diameter of the sealing sleeve 11.

The length of the sealing sleeve 11 is at least fifty percent of the length of the hub 19 of the guide vane.

A base 25 is installed at the entrance to the housing 7, and a head 26 of the pump section is installed at the exit.

The installation of a submersible multistage centrifugal pump works as follows.

When the electric motor shaft 1 rotates, torque is transmitted through the hydraulic protection shafts 2 and the gas separator 3, the shaft 9 of the pump 4 to the impellers 8. The formation fluid enters the pump section 4 through the base 25, sequentially passes through the impellers 8, guide vanes 6, bearings 10, exits through the head 26 and tubing pipes 5 to the surface. In this case, the pressure of the formation fluid increases.

When the impeller 8 rotates, due to the presence of a blade rim 20 on the drive disk 12, the liquid in the bosom between this disk 12 and the lower disk 16 of the guide vane 8 rotates at a higher speed than in the absence of a blade rim 20. A torus-shaped vortex arises; due to a change in speed, the pressure can be increased at low flow rates and optimize the amount of axial force acting on wheel 8.

The helical groove 24, made on the outer diameter of the sealing sleeve 11, makes it possible to reduce leakage due to hydrodynamics, increase wear resistance and the permissible content of mechanical impurities by eliminating mechanical impurities from the friction pair.

The helical groove 23, made on the inner diameter of the shell of the guide vane 6, makes it possible to increase the permissible content of free gas due to dispersion and mechanical impurities due to the effective transfer from this stage to the entrance to the next guide vane.

The guide apparatus is made of cast iron, which contains, in particular, silicon, manganese, chromium, cerium, phosphorus and sulfur, with the following content of these elements, wt. %:

carbon 3.5-3.9 silicon 2.1-2.7 manganese 0.4-0.6 phosphorus <0.3 cerium <0.03 boron <0.01 sulfur <0.05 chromium <0.12 iron rest

The guide apparatus is made of cast iron, which contains, in particular, silicon, manganese, chromium, nickel, copper, phosphorus and sulfur, with the following content of these elements, wt. %:

carbon <3 silicon 1.0-2.8 manganese 0.5-1.5 nickel 13.5-17.5 copper 5.0-8.0 chromium 1.5-2.5 aluminum <0.3 sulfur <0.05 phosphorus <0.25 iron rest

The above composition of cast iron allows you to optimize the cost of the product.

Claims (13)

1. The method of operation of the installation of a submersible multistage centrifugal pump, which consists in lifting the reservoir fluid in stages containing a guide vane and an impeller made of materials that cannot come into contact with each other during operation, axial supports are installed between the guide vane and the impeller, in the composition of which includes support washers; a sealing sleeve is installed on the shaft for each stage, eliminating leakage, made of a material capable of being in a friction pair with the material from which the mating surface of the guide vane is made, characterized in that the impeller is made of a polymer material, with a low rate of salt deposition, low weight, smooth surface of the flow part, with high corrosion resistance, a gap is made between the wheel hub and the hub of the guide vane, the size of which is guaranteed to exclude contact of the impeller and the guide vane during operation, A blade rim is made on the driving disk of the impeller, which provides the optimal amount of axial force acting on the impeller. 2. The method according to claim 1, characterized in that structural elements are made on the inner diameter of the guide vane shell and on the outer diameter of the sealing sleeve to remove mechanical impurities and disperse large bubbles of free gas. 3. Installation of a submersible multistage centrifugal pump, which includes a motor, hydraulic protection, a pump containing a shaft, one stage containing a guide vane consisting of a shell, a lower disk with a hub, an upper disk, blades are made between the disks, an impeller that contains a driving disk with a hub and a covering disk, blades are placed between the disks, and between the upper disk of the guide vane and the driven disk of the impeller, between the hub of the guide vane and the driving disk of the impeller, axial supports are installed, which include support washers, on the shaft for each stage a sealing sleeve is installed, the length of which is at least fifty percent of the length of the guide vane hub, characterized in that the impeller is made of a polymer thermoplastic material, a gap is made between the wheel hub and the hub of the guide vane, the value of which is twenty percent greater than the gap between the sealing sleeve and the hub of the guide vane, a blade rim is made on the drive disk of the impeller, the height of the blade rim does not exceed the minimum distance between the driving and covering disks of the impeller, the angle between each blade of the blade rim at its periphery and the radius ranges from minus 30° to plus 30°. 4. The installation according to claim 3, characterized in that there are roundings made between the side edges of each blade of the blade ring and the drive disk, the radius of the roundings is from 0.1 to 0.8 of the height of the blade ring. 5. Installation according to claim 3, characterized in that the pump shaft rests on the engine hydraulic protection shaft. 6. Installation according to claim 3, characterized in that a groove is made on the inner diameter of the guide vane hub, on the side of the impeller hub. 7. Installation according to claim 3, characterized in that a helical groove is made on the inner diameter of the guide vane shell. 8. Installation according to claim 3, characterized in that a helical groove is made on the outer diameter of the sealing sleeve. 9. Installation according to claim 3, characterized in that the hub of the guide vane is made of a polymer material. 10. Installation according to claim 3, characterized in that the guide apparatus is made of cast iron, which contains, in particular, silicon, manganese, chromium, cerium, phosphorus and sulfur, with the following content of these elements, wt. %: carbon 3.5-3.9 silicon 2.1-2.7 manganese 0.4-0.6 phosphorus <0.3 cerium <0.03 boron <0.01 sulfur <0.05 chromium <0.12 iron rest 11. Installation according to claim 3, characterized in that the guide apparatus is made of cast iron, which contains, in particular, silicon, manganese, chromium, nickel, copper, phosphorus and sulfur, with the following content of these elements, wt. %: carbon < 3 silicon 1.0-2.8 manganese 0.5-1.5 nickel 13.5-17.5 copper 5.0-8.0 chromium 1.5-2.5 aluminum <0.3 sulfur <0.05 phosphorus <0.25 iron rest