Screw pump stator, screw pump friction pair and screw pump

Abstract

The invention belongs to the technical field of oil and gas development of ultra-deep wells and ultra-deep wells, and discloses a screw pump stator, a screw pump friction pair and a screw pump. The surface of the screw pump stator is provided with a bionic non-smooth array, the bionic non-smooth array comprises a plurality of curved surface texture monomers, the plurality of curved surface texture monomers are arranged in multiple rows and multiple columns, each curved surface texture monomer comprises a main body part and two spherical crown parts, and the two spherical crown parts are arranged at the two ends of the main body part in the length direction. And the main body part and the spherical crown part form an ellipsoid shell-shaped bionic curved surface. Friction wear between the screw pump stator and the screw pump rotor can be reduced, so that friction torque generated in the working process of the screw pump stator and the screw pump rotor is reduced, particularly, starting torque of the screw pump can be reduced, and then energy consumption of the screw pump is reduced.

Description

Technical Field

[0001] This invention relates to the field of deep and ultra-deep well oil and gas development technology, and in particular to a screw pump stator, a screw pump friction pair, and a screw pump. Background Technology

[0002] Deep and ultra-deep well oil and gas development is an important area for increasing reserves and production in my country's oil and gas industry. Screw pumps have been used in drilling and oil production engineering since the 1980s and have now become one of the most important lifting devices in crude oil extraction, with outstanding advantages in high-viscosity, high-sand, and gas-bearing wells.

[0003] In deep and ultra-deep well oil production projects, the stator and rotor of screw pumps are in a state of friction for extended periods, which can easily cause wear on the rubber stator and lead to pump failure. In the high-temperature environment at the bottom of the well, if the rubber stator heats up too quickly or heat dissipation is uneven, it can easily cause accidents such as delamination, rubber breakage, rubber swelling causing pump jamming, and pump burnout. Furthermore, at high temperatures, the frictional torque between the stator and rotor increases, resulting in a large starting torque, directly affecting the working performance and service life of the screw pump. Therefore, it is urgent to reduce the frictional wear between the rubber stator and rotor to extend the service life of rubber screw pumps. Summary of the Invention

[0004] The purpose of this invention is to provide a screw pump stator, a screw pump friction pair, and a screw pump to solve the problem of high friction and wear of the screw pump stator, thereby extending the service life of the rubber screw pump.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] The present invention provides a screw pump stator, the surface of which has a biomimetic non-smooth array. The biomimetic non-smooth array includes multiple curved textured units, which are arranged in multiple rows and columns. Each curved textured unit includes a main body and two spherical caps, which are located at both ends of the main body along its length. The main body and the spherical caps form an ellipsoidal biomimetic curved surface.

[0007] Optionally, along the length of the main body, multiple curved textured units are connected end to end to form a unit column, and the multiple unit columns are arranged sequentially without interval along the width of the main body to form the biomimetic non-smooth array.

[0008] Optionally, the biomimetic non-smooth array is arranged along the surface helical direction of the screw pump stator.

[0009] Optionally, any two adjacent single-unit columns may have their multiple curved textured single units arranged aligned or staggered along the width direction of the main body.

[0010] Optionally, at least 50% of the surface area of ​​the screw pump stator has the biomimetic non-smooth array.

[0011] Optionally, the aspect ratio of the biomimetic surface is greater than 50.

[0012] Optionally, the length L of the biomimetic surface is 8-16 mm; the height H of the biomimetic surface is 80-160 μm.

[0013] Optionally, the radius of the spherical crown is 0.5-1.6 mm.

[0014] The present invention also provides a screw pump friction pair, including a screw pump rotor and the screw pump stator provided by the present invention, wherein the screw pump rotor is rotatably disposed within the screw pump stator.

[0015] The present invention also provides a screw pump, including a motor and the screw pump friction pair provided by the present invention, wherein the output shaft of the motor is connected to the screw pump rotor of the screw pump friction pair.

[0016] The beneficial effects of this invention are:

[0017] The screw pump stator provided by this invention designs at least a portion of the working surface of the screw pump stator as a biomimetic non-smooth array. The surfaces of the multiple curved texture units constituting the biomimetic non-smooth array are all biomimetic curved surfaces. This reduces the frictional wear between the screw pump stator and the screw pump rotor, thereby reducing the frictional torque generated by the screw pump stator and the screw pump rotor during operation, especially reducing the starting torque of the screw pump, and thus reducing the energy consumption of the screw pump. The curved texture unit of this invention adopts a composite texture including a main body and a spherical crown, avoiding the problem of increased grinding caused by dead angles between a single texture and the base surface. The composite texture and the surface structure of the ellipsoidal shell-shaped biomimetic curved surface greatly reduce the friction coefficient between the screw pump stator and the screw pump rotor, and further reduce the wear of the screw pump stator. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the screw pump stator provided in an embodiment of the present invention;

[0019] Figure 2 yes Figure 1 Enlarged structural diagram of region A in the middle;

[0020] Figure 3 This is a cross-sectional view of the stator of the screw pump provided in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of the curved textured single unit in the stator of the screw pump provided in an embodiment of the present invention;

[0022] Figure 5This is a front view of a single curved textured unit in the stator of a screw pump provided in an embodiment of the present invention.

[0023] In the picture:

[0024] 100. Screw pump stator; 1. Single-unit row; 11. Curved textured single unit; 111. Main body; 112. Spherical crown. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0026] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0028] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0029] This invention provides a screw pump stator 100, such as... Figures 1-5As shown, the surface of the screw pump stator 100 has a biomimetic non-smooth array. The biomimetic non-smooth array includes multiple curved texture units 11, which are arranged in multiple rows and columns. Each curved texture unit 11 includes a main body 111 and two spherical caps 112. The two spherical caps 112 are located at both ends of the length direction of the main body 111. The main body 111 and the spherical caps 112 form an ellipsoidal shell-shaped biomimetic curved surface.

[0030] The screw pump stator 100 provided in this embodiment of the invention cooperates with the screw pump rotor to form a friction pair. In deep and ultra-deep well oil extraction conditions, the screw pump stator 100 is made of rubber and is a component that is easily damaged in the screw pump. In this embodiment of the invention, the surface of the screw pump stator 100, which is the working surface that mates with the screw pump rotor, is designed with a structure featuring a biomimetic non-smooth array. The surfaces of the multiple curved texture units 11 that make up the biomimetic non-smooth array are all biomimetic curved surfaces, which can reduce the frictional wear between the screw pump stator 100 and the screw pump rotor, thereby reducing the frictional torque generated between the screw pump stator 100 and the screw pump rotor during operation, especially reducing the starting torque of the screw pump, and thus reducing the energy consumption of the screw pump. In this embodiment of the invention, the curved texture unit 11 adopts a composite texture including a main body 111 and a spherical crown 112, avoiding the problem of increased grinding caused by dead angles between a single texture and the base surface. The composite texture and the surface structure of the ellipsoidal shell-shaped biomimetic curved surface greatly reduce the friction coefficient between the screw pump stator 100 and the screw pump rotor, and further reduce the wear of the screw pump stator 100.

[0031] It should be noted that in this embodiment of the invention, the curved texture unit 11 is a biomimetic structure. The main body 111 and the spherical crown 112 are respectively biomimetic curved surface shapes of pangolin scales and dung beetle shells. Multiple curved texture units 11 form a multi-row, multi-column biomimetic non-smooth array, which is a biomimetic representation of the body surface of organisms and animals. In terms of wear resistance, pangolins, dung beetles, and mole crickets can move through sand and soil without damaging their body surfaces because the non-smooth shape of their body surfaces has excellent wear resistance and compression resistance. In terms of drag reduction, the body surfaces of soil animals such as earthworms exhibit various non-smooth geometric shapes, which enable them to reduce soil sliding resistance and facilitate movement in the soil. This invention designs the surface of the screw pump stator 100 as a biomimetic non-smooth array, altering the surface morphology of the stator 100 and thereby reducing the friction between the stator 100 and the rotor. This reduces the torque generated by friction between the rotor and stator 100 during rotor rotation, resulting in lower starting torque and energy consumption. This ultimately improves the service life and performance of the screw pump.

[0032] Optionally, along the length of the main body 111, multiple curved textured units 11 are connected end to end to form a unit column 1, and the multiple unit columns 1 are arranged sequentially without interval along the width of the main body 111 to form a biomimetic non-smooth array.

[0033] like Figure 2 As shown, on the surface of the screw pump stator 100, multiple curved textured units 11 are arranged in multiple rows and columns. Each unit column 1 includes multiple curved textured units 11 along the length direction of the main body 111. The curved textured units 11 are connected end to end. Multiple unit columns 1 are arranged along the width direction of the main body 111. It can be understood that because each curved textured unit 11 has an ellipsoidal shell-shaped biomimetic curved surface, the multiple curved textured units 11 are arranged to form a biomimetic non-smooth curved surface, which has drag reduction and wear resistance properties, thereby realizing the wear reduction and drag reduction of the friction pair composed of the screw pump stator 100 and the screw pump rotor.

[0034] Optionally, the biomimetic non-smooth array is arranged along the helical direction of the surface of the screw pump stator 100.

[0035] It is understandable that the friction surfaces between the screw pump stator 100 and the screw pump rotor are helical. Arranging the biomimetic smooth array along the helical direction can further reduce the surface friction coefficient of the screw pump stator 100. Specifically, as... Figure 2 and Figure 3 As shown, multiple single-unit rows 1 are arranged in the spiral direction of the screw pump stator 100. During the rotation of the screw pump rotor, they always follow the extension direction of the multiple single-unit rows 1, which makes the transition between the screw pump rotor and the surface of the curved textured single unit 11 smooth and the friction wear of the friction pair small.

[0036] Optionally, multiple curved textured units 11 of any two adjacent unit columns 1 are arranged aligned or staggered along the width direction of the main body 111.

[0037] like Figure 2The diagram shows a structural schematic of multiple unit columns 1 with the same number of curved textured units 11 arranged in alignment, each unit column 1 having the same number of curved textured units 11. In some embodiments, when the curved textured units 11 in two adjacent unit columns 1 are staggered, the number of curved textured units 11 included in each unit column 1 can be the same or different. For the staggered arrangement, it can be formed by alternating two types of unit columns 1 with a fixed stagger distance, or by multiple unit columns 1 being staggered sequentially at a fixed stagger distance. The stagger distance is the offset dimension along the length direction of the main body 111, and the stagger distance is less than the length of the main body 111. Furthermore, the staggered arrangement is arranged sequentially in the direction of the helix of the screw pump stator 100, which facilitates a stable and smooth friction contact surface during the rotation of the screw pump rotor, reducing frictional wear on the screw pump stator 100.

[0038] Optionally, at least 50% of the surface area of ​​the screw pump stator 100 has a biomimetic non-smooth array.

[0039] The screw pump stator 100 provided in this embodiment of the invention has this biomimetic non-slip array on 50% to 100% of the surface that mates with the screw pump rotor. Specifically, the design of specific parts can be tailored to the friction and wear characteristics of the screw pump stator 100 surface to improve its lubrication conditions. Based on the friction and wear characteristics of existing rubber-material screw pump stators 100, the biomimetic non-slip array, with a projected area of ​​at least 50% of the screw pump stator 100 surface and arranged sequentially along the helical rotation direction of the screw pump rotor, can change the lubrication medium state of the friction pair and improve its lubrication conditions.

[0040] Optionally, the aspect ratio of the biomimetic surface is greater than 50.

[0041] The length of the biomimetic surface refers to the sum of the length of the main body 111 and the radii of the two spherical caps 112 along the length direction of the main body 111. The depth of the biomimetic surface refers to the maximum protrusion height of the main body 111 and / or the spherical caps 112, that is, the height of the protrusion of the main body 111 and the spherical caps 112 relative to the smooth surface of the original screw pump stator 100. The ratio of the length to the width of the biomimetic surface is the length-to-depth ratio. A length-to-depth ratio greater than 50 results in a large angle between the original smooth surface of the screw pump stator 100 and the highest point of the surface of the biomimetic non-smooth array, but with a gentle slope. In the prior art, there are also embodiments that provide non-smooth surfaces on the surface of the screw pump stator 100. However, because the non-smooth surfaces are rhomboid or strip-shaped, they have sharp corners, resulting in large grinding and cutting problems during the rotation of the screw pump rotor. If the angle between the screw pump stator 100 and the highest point of its original smooth surface is less than or equal to 90°, it can easily cause grinding wear on the screw pump stator 100. In this embodiment of the invention, such as... Figure 5 The biomimetic surface formed by the main body 111 and the spherical cap 112 has a length L of 8-16 mm and a height H of 80-160 μm. The aspect ratios vary by orders of magnitude, with a maximum aspect ratio reaching 200. However, due to the use of a composite texture combining the main body 111 and the spherical cap 112, the problem of excessive dead angles between the texture and the substrate surface, which exists under a single morphology, is avoided, preventing increased grinding of the friction pair after prolonged operation.

[0042] Optionally, the radius of the spherical crown 112 is 0.5-1.6 mm.

[0043] In this embodiment of the invention, the spherical crown 112 is preferably a quarter-spherical shell, having the same maximum protrusion height as the main body 111, and the main body 111 and the spherical crown 112 smoothly form an ellipsoidal shell with a smooth biomimetic curved surface. The specific radius of the spherical crown 112, as well as the length and height of the main body 111, are determined according to the working depth of the screw pump. The above-mentioned preferred dimensions are particularly suitable for the surface design requirements of the rubber screw pump stator 100 in deep and ultra-deep wells, which can improve the service life of the screw pump and reduce energy consumption.

[0044] This invention also provides a screw pump friction pair, including a screw pump rotor and a screw pump stator 100 provided by this invention. It is applicable to deep and ultra-deep well screw pumps, wherein the screw pump is a rubber screw pump, and the rubber stator is the screw pump stator 100. This invention, by changing the surface morphology of the rubber stator, reduces the starting torque of the rubber screw pump rotor and improves the wear resistance, lubrication, and sealing performance of the rubber stator, thereby extending the service life of the rubber screw pump. It provides a surface-textured rubber stator screw pump with low starting static torque, strong adaptability, long service life, and low energy consumption for deep and ultra-deep well oil and gas extraction.

[0045] The friction pair consisting of the screw pump stator 100 and the screw pump rotor provided in this embodiment of the invention was tested under lubrication conditions such as water / oil-water mixture. The results show that the friction coefficient of the friction pair is directly proportional to the aspect ratio of the curved textured unit 11. By selecting a suitable surface density of 50-100% (i.e., more than 50% of the surface of the screw pump stator 100 is a biomimetic non-smooth array), when the aspect ratio is greater than 50, compared with conventional rubber stators with smooth surfaces, the friction coefficient of the friction pair can be reduced by 24.3-61.7%, and the wear amount can be reduced by 11-23%. The experimental results show that the biomimetic non-smooth array improves the wear resistance of the screw pump stator 100, improves the lubrication conditions of the friction pair consisting of the screw pump stator 100 and the screw pump rotor, helps to reduce the friction torque of the friction pair, thereby reducing the starting torque of the screw pump, and thus reducing the energy consumption of the screw pump. This is suitable for the performance requirements of screw pumps in deep and ultra-deep wells. This invention can be applied to the petroleum industry, food industry and other fields, and has considerable potential for promotion.

[0046] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A screw pump stator, characterized in that, The surface of the screw pump stator (100) has a biomimetic non-smooth array, which includes multiple curved texture units (11). The multiple curved texture units (11) are arranged in multiple rows and columns. Each curved texture unit (11) includes a main body (111) and two spherical caps (112). The two spherical caps (112) are located at both ends of the length direction of the main body (111). The main body (111) and the spherical caps (112) form an ellipsoidal shell-shaped biomimetic curved surface.

2. The screw pump stator according to claim 1, characterized in that, Along the length of the main body (111), a plurality of curved textured units (11) are connected end to end to form a unit column (1), and the plurality of unit columns (1) are arranged sequentially without interval along the width of the main body (111) to form the biomimetic non-smooth array.

3. The screw pump stator according to claim 2, characterized in that, The biomimetic non-smooth array is arranged along the spiral direction of the surface of the screw pump stator (100).

4. The screw pump stator according to claim 3, characterized in that, Any two adjacent single-unit columns (1) are arranged or staggered along the width direction of the main body (111) with multiple curved textured single units (11).

5. The screw pump stator according to any one of claims 1-4, characterized in that, At least 50% of the surface area of ​​the screw pump stator (100) has the biomimetic non-smooth array.

6. The screw pump stator according to claim 1, characterized in that, The aspect ratio of the biomimetic surface is greater than 50.

7. The screw pump stator according to claim 6, characterized in that, The length L of the biomimetic surface is 8-16mm; the height H of the biomimetic surface is 80-160μm.

8. The screw pump stator according to claim 7, characterized in that, The radius of the spherical crown (112) is 0.5-1.6 mm.

9. A screw pump friction pair, characterized in that, It includes a screw pump rotor and a screw pump stator (100) as described in any one of claims 1-8, wherein the screw pump rotor is movably disposed within the screw pump stator.

10. A screw pump, characterized in that, It includes a motor and the screw pump friction pair as described in claim 9, wherein the output shaft of the motor is connected to the screw pump rotor of the screw pump friction pair.

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