Self-cooling type oil extraction single-screw pump

Abstract

The invention relates to the technical field of oil extraction processes, in particular to a self-cooling type oil extraction single-screw pump, which comprises an oil extraction conveying mechanism, a cooling mechanism and a control mechanism, and the self-cooling mechanism cools circulating oil in the stator bushing by absorbing heat of the stator, and comprises a first cooling channel and a second cooling channel which are connected with the stator bushing and are matched with each other to provide a cooling circulation space for the oil, and the relative spatial configuration of the first cooling channel and the second cooling channel is of a double-helix structure. The self-heat-dissipation performance of the rubber stator of the oil extraction single-screw pump is improved, the rubber wall thickness uniformity and working performance of the stator of the screw pump are improved, and the damage caused by the heat accumulation effect generated by the rubber stator and the uneven wall thickness is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of oil production technology, in particular to a self-cooling single screw pump for oil production. Background Art

[0002] In the prior art, a single screw pump for oil production is a mechanical device used for oil production, which uses the rotational motion of a single screw to lift crude oil. The main advantages of this pump are simple structure, stable operation, easy maintenance, and the ability to adapt to oil wells with high viscosity and high sand content. A closed cavity is formed between the screw and the pump casing of the single screw pump. As the screw rotates, the oil is continuously sucked in and discharged. The single screw pump for oil production has the technical advantages of both a volumetric pump and a centrifugal pump. It has a simple structure, a small one-time investment, can continuously lift the medium, has a stable load during operation, has low loss, and high efficiency. It is one of the mechanical oil production methods with the lowest energy consumption and the highest efficiency, and is used in batches in various domestic oil fields. Single screw pumps are usually made of metal materials to withstand the harsh working environment underground. The pump can be driven by either electric or hydraulic. In the electric drive mode, the motor drives the screw to rotate through a reducer; the hydraulic drive uses the pressure of the underground fluid to drive the screw. In order to improve oil recovery efficiency, the design of single-screw pumps is constantly optimized, including improving the geometry of the screw and pump casing, improving the corrosion resistance and wear resistance of materials, and optimizing the working performance of the pump.

[0003] Chinese patent publication number: CN102434458A discloses a 2 / 3 type double-headed single screw pump suitable for oilfield production, including a 2 / 3 type double-headed single screw pump body, characterized in that: the double-headed spiral rotor surface of the 2 / 3 type double-headed single screw pump is evenly compounded with a nylon layer, and the stator is a die-cast metal stator. It can be seen that the 2 / 3 type double-headed single screw pump suitable for oilfield production has the problems of decreased working performance of the spiral pump due to the friction of the rotor running on the stator, which increases the temperature of the stator, and decreased operating stability of the spiral pump due to gas inhalation at the stator suction port. Summary of the invention

[0004] To this end, the present invention provides a self-cooling single screw pump for oil production to overcome the problems of poor working performance and premature product failure caused by heat accumulation effect in thicker parts of the rubber stator during the operation of the screw pump in the prior art.

[0005] To achieve the above object, the present invention provides a self-cooling oil production single screw pump, comprising: The oil extraction and conveying mechanism comprises a rotor which rotates in the oil conveying direction to provide oil suction power and a stator which is connected to the rotor to form an oil closed conveying channel with the rotor, wherein the stator comprises a stator bushing which collects oil by cooperating with the rotor and a stator outer tube which is connected to the stator bushing to support the stator bushing; A self-cooling mechanism is connected to the stator and cools the oil circulating inside the stator bushing by absorbing the heat of the stator. The self-cooling mechanism includes a first cooling channel and a second cooling channel connected to the stator bushing and cooperating with each other to provide a cooling circulation space for the oil. The relative spatial configuration of the first cooling channel and the second cooling channel is a double helix structure.

[0006] Furthermore, the pitches of the first cooling channel and the second cooling channel are equal.

[0007] Further, a pitch of the first cooling channel or the second cooling channel is twice a pitch of the stator bushing.

[0008] Further, the midpoint of the first cooling channel and the midpoint of the second cooling channel are at the same distance in the cross section along the oil inlet direction.

[0009] Furthermore, the first cooling channel includes a plurality of external communication holes and an internal communication hole provided on the suction end of the stator for sucking the cooling oil; The second cooling channel has the same internal structure as the first cooling channel.

[0010] Furthermore, a single external communication hole is provided on the stator outer tube to discharge the cooling oil to the area outside the stator outer tube.

[0011] Furthermore, the number of the external communicating holes is positively correlated with the pitch of the stator bushing.

[0012] Further, the projection distances of the distances between every two adjacent external communication holes in the first cooling channel and the second cooling channel on the stator center line are the same.

[0013] Furthermore, the rotor is also used to suck the cooling oil into the oil closed delivery channel when the cooling oil flows from the external connecting port into the cooling channel and flows out through the internal connecting port to merge with the oil in the oil suction area of ​​the stator.

[0014] Furthermore, the rotor circulates and squeezes the cooling channel during the meshing process with the stator so that the cooling oil is transported from the outer communicating hole to the inner communicating hole.

[0015] Furthermore, during the periodic rotation and meshing process, the rotor and the stator allow oil to be repeatedly sucked in and discharged through the first cooling channel and the second cooling channel to dissipate heat from the stator.

[0016] Furthermore, the stator is also used to form a vacuum space between the outer wall of the rotor and the inner wall of the stator bushing during the rotation of the rotor so that the oil flows in the oil delivery direction.

[0017] Furthermore, the material of the stator bushing is rubber.

[0018] Compared with the prior art, the beneficial effect of the present invention lies in that the system of the present invention, by setting up an oil production and transportation mechanism and a self-cooling mechanism, can improve the uniformity of the stator wall thickness of the single-screw pump by setting a cooling channel in the stator bushing due to the uneven thickness of the inner wall of the stator, thereby improving the working performance of the single-screw pump.

[0019] Furthermore, the system of the present invention is provided with a first cooling channel and a second cooling channel. Since the thickness of the rubber is uneven when the stator bushing is cast and rubber is a poor conductor of heat, the heat generated by the operation of the rotor causes a higher temperature rise in the thicker rubber part. In addition, the swelling of the medium in the thicker rubber part is also greater, the interference fit between the stator and the rotor is greatly increased, and the friction and frictional heat between the stator and the rotor are also increased, resulting in reduced system efficiency. The first cooling channel and the second cooling channel are arranged around the inside of the stator bushing to continuously dissipate heat from the stator, thereby improving the working stability of the single screw rod and improving the uniformity of the wall thickness of the rubber stator bushing.

[0020] Furthermore, the system of the present invention realizes communication with the outside when the rotor is working and realizes the circulation of oil circuits and continuous heat absorption and heat dissipation by setting an internal connecting hole and an external connecting hole group. The cooling oil enters the cooling channel through the external connecting hole to absorb heat from the stator bushing and is discharged from the external connecting hole to achieve heat dissipation, which helps to exchange the cooling oil in the cooling channel with the collected oil, thereby improving the heat dissipation performance of the stator.

[0021] Furthermore, the system described in the present invention forms a cooling channel by setting up a cooling channel and an external area to form a loop. The rotor squeezes the cooling oil during operation. The cooling oil flows up and down in the cooling channel and absorbs heat at different positions in the stator sleeve. After the cooling oil flows through the cooling channel and absorbs heat, it merges with the oil at the suction end of the stator to carry the heat out, thereby enhancing the heat dissipation performance of the self-cooling mechanism and further enhancing the working performance of the single-screw pump.

[0022] Furthermore, the system of the present invention increases the flow length of the cooling oil in the channel and prolongs the contact time between the coolant and the channel wall by setting a double helix structure of the cooling channel, which helps to improve the heat exchange efficiency. Compared with a straight channel, it can also reduce sharp turns and mutations in the flow, thereby reducing the flow resistance of the fluid, reducing the energy consumption of the pump, and enhancing the working performance of the single-screw pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is an overall structural diagram of a self-cooling oil production single screw pump according to an embodiment of the present invention; Figure 2 Another angle structural diagram of the self-cooling oil production single screw pump according to an embodiment of the present invention; Figure 3 This is a structural diagram of the external communication hole of the self-cooling oil production single screw pump according to an embodiment of the present invention; Figure 4 This is a structural diagram of the cooling channel of a self-cooling oil production single screw pump according to an embodiment of the present invention; Figure 5 This is a structural diagram of a cooling channel with a non-circular cross section of a self-cooling oil production single screw pump according to an embodiment of the present invention; Explanation of the accompanying drawings: 1-rotor, 21-external connecting hole of the first cooling channel, 22-external connecting hole of the second cooling channel, 31-internal connecting hole of the first cooling channel, 32-internal connecting hole of the second cooling channel, 4-statator outer tube, 5-stator bushing, 6-first cooling channel, 7-second cooling channel, 8-temperature sensor, 9-inner wall of the stator bushing, 10-outer wall of the rotor. DETAILED DESCRIPTION

[0024] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0026] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0027] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] See also Figure 1 , Figure 2 , Figure 3 , Figure 4 as well as Figure 5 As shown, they are respectively an overall structural diagram of the self-cooling oil production single screw pump according to an embodiment of the present invention, a structural diagram from another angle, a structural diagram of the external connecting hole, a structural diagram of the cooling channel, and a structural diagram of the cooling channel in another form.

[0029] Embodiment 1, Embodiment 1 of the present invention provides a self-cooling oil production single screw pump, comprising: The oil extraction and delivery mechanism comprises a rotor 1 which rotates in the oil delivery direction to provide oil suction power and a stator which is connected to the rotor 1 to form an oil closed delivery channel with the rotor 1, wherein the stator comprises a stator bushing 5 which collects oil by cooperating with the rotor 1 and a stator outer tube 4 which is connected to the stator bushing 5 to support the stator bushing 5; A self-cooling mechanism is connected to the stator and cools the oil flowing inside the stator bushing 5 by absorbing the heat of the stator. The mechanism includes a first cooling channel 6 and a second cooling channel 7 which are connected to the stator bushing 5 and cooperate with each other to provide a cooling circulation space for the oil. The relative spatial configuration of the first cooling channel 6 and the second cooling channel 7 is a double helix structure.

[0030] Specifically, the working process of the self-cooling oil production single screw pump described in the present invention is as follows: the oil will enter the stator suction port from the upper external connecting hole through the coolant channel and the internal connecting hole, merge with the produced liquid from the lower part of the pump, and be lifted to the ground by the screw pump; at the same time, during the meshing process between the rotor 1 and the stator, the liquid in the coolant channel is circulated and squeezed to flow up and down: upward through the external connecting hole to form a connecting passage with the outside of the stator outer tube 4, downward through the internal connecting hole to connect with the stator suction port, and force the stator rubber to dissipate heat. The above-mentioned oil is repeatedly sucked in and discharged through the coolant channel to dissipate heat for the stator, and is repeated and automatically performed during the periodic rotation meshing process between the rotor 1 and the stator, thereby avoiding heat accumulation and temperature rise of the stator rubber.

[0031] In practice, the system of the present invention is provided with an oil production and transportation mechanism and a self-cooling mechanism. Since the uneven thickness of the inner wall of the stator causes cohesive heat to rise in the stator, which makes it difficult for the stator to dissipate heat, a cooling channel is provided in the stator bushing 5 to improve the uniformity of the stator wall thickness of the single-screw pump, thereby further improving the working performance of the single-screw pump.

[0032] Specifically, the pitches of the first cooling channel 6 and the second cooling channel 7 are equal.

[0033] Specifically, the pitch of the first cooling channel 6 or the second cooling channel 7 is twice the pitch of the stator bushing 5 .

[0034] Specifically, the midpoints of the first cooling channel 6 and the second cooling channel 7 are at the same distance in the cross section along the oil inlet direction.

[0035] Specifically, the cross-sectional shape of the cooling channel can be set to be circular or non-circular as long as the above function can be achieved.

[0036] In practice, the system of the present invention is provided with a first cooling channel 6 and a second cooling channel 7. Since the thickness of the rubber is uneven when the stator bushing 5 is cast by rubber and rubber is a poor conductor of heat, the heat generated by the operation of the rotor 1 causes a higher temperature rise in the thicker rubber part. In addition, the swelling of the medium in the thicker rubber part is also greater, the interference fit between the stator and the rotor is greatly increased, and the friction and frictional heat between the stator and the rotor are also increased, resulting in reduced system efficiency. The first cooling channel 6 and the second cooling channel 7 are arranged around the inside of the stator bushing 5 to continuously dissipate heat from the stator, thereby improving the working stability of the single screw rod and improving the uniformity of the wall thickness of the rubber stator bushing 5.

[0037] Specifically, the first cooling channel 6 includes a plurality of external communication holes and an internal communication hole provided on the suction end of the stator for sucking the cooling oil; The second cooling channel 7 has the same internal structure as the first cooling channel 6 .

[0038] Specifically, the first cooling channel 6 is provided with a plurality of first cooling channel 6 outer connecting holes 21 and a first cooling channel 6 inner connecting hole 31 , and the second cooling channel 7 is provided with a plurality of second cooling channel 7 outer connecting holes 22 and a second cooling channel 7 inner connecting hole 32 .

[0039] Specifically, a single external communication hole is provided on the stator outer tube 4 to discharge the cooling oil to the outer area of ​​the stator outer tube 4 .

[0040] Specifically, the number of the external communication holes is positively correlated with the pitch of the stator bushing 5 .

[0041] Specifically, the projection distances of the distances between each two adjacent external communication holes in the first cooling channel 6 and the second cooling channel 7 on the stator center line are the same.

[0042] In practice, the pitch of the stator liner 5 is positively correlated with the number of external connecting holes. For example, when the pitch of the stator liner 5 is within 200 mm, the number of external connecting holes on a cooling channel is set to 1-3. When the pitch of the stator liner 5 is 200 mm-300 mm, the number of external connecting holes on a cooling channel is set to 4-6. When the pitch of the stator liner 5 exceeds 300 mm, the number of external connecting holes on a cooling channel increases by 2-4 for every 100 mm above the pitch. The specific number of external connecting holes on a cooling channel is appropriately adjusted according to the stator length.

[0043] In practice, the system of the present invention realizes oil circulation and continuous heat absorption and heat dissipation by setting an internal connecting hole and an external connecting hole group when the rotor 1 is working. The cooling oil enters the cooling channel through the external connecting hole to absorb heat from the stator bushing 5 and is discharged from the external connecting hole to dissipate heat, which helps to exchange the cooling oil in the cooling channel with the collected oil, thereby improving the heat dissipation performance of the stator.

[0044] Specifically, the rotor 1 is also used for the stator to suck the cooling oil into the oil closed delivery channel when the cooling oil flows from the external connecting port into the cooling channel and flows out through the internal connecting port to merge with the oil in the oil suction area of ​​the stator.

[0045] Specifically, the rotor 1 circulates and squeezes the cooling channel during the meshing process with the stator so that the cooling oil is transported from the outer communication hole to the inner communication hole.

[0046] Specifically, during the periodic rotation and meshing process of the rotor 1 and the stator, the oil is repeatedly sucked in and discharged through the first cooling channel 6 and the second cooling channel 7 to dissipate the heat of the stator.

[0047] Specifically, the stator is also used to form a vacuum space between the rotor outer wall 12 and the stator sleeve inner wall 11 during the rotation of the rotor 1 so that the oil flows in the oil delivery direction.

[0048] Specifically, the material of the stator bushing 5 is rubber.

[0049] Embodiment 2, Embodiment 2 of the present invention is further provided with a temperature sensor 8 on the basis of Embodiment 1, which is respectively connected to the stator and the self-cooling mechanism to detect the temperature of the contact position between the stator outer tube 4 and the stator bushing 5; A controller is connected to the temperature sensor 8 and the rotor 1, respectively, and is used to determine the operating stability of the rotor 1 according to the temperature difference of the stator bushing 5 to determine whether to adjust the rotation speed of the rotor 1, and after the single-screw pump stops working, determine the degree of friction between the stator bushing 5 and the rotor 1 according to the temperature reduction rate of the stator bushing 5.

[0050] In practice, the preferred embodiment of the controller is a small single chip microcomputer.

[0051] Specifically, a single temperature sensor 8 is arranged on the inner wall of the stator outer tube 4 to detect the corresponding temperature of the stator liner 5 in the area where the single temperature sensor 8 is located; a plurality of circles of the temperature sensors 8 are arranged at equal intervals on the inner wall of the stator outer tube 4, and the number of the temperature sensors 8 in a single circle is determined according to the diameter of the stator outer tube 4.

[0052] Specifically, the temperature sensors 8 of a single turn are distributed at equal intervals along the diameter of the stator outer tube 4 .

[0053] In implementation, the number of temperature sensors 8 in a single turn is positively correlated with the diameter of the stator outer tube 4. For example, when the diameter of the stator outer tube 4 is 150 mm, the number of temperature sensors 8 in a single turn is set to 4; when the diameter of the stator outer tube 4 is 200 mm, the number of temperature sensors 8 in a single turn is set to 5.

[0054] Specifically, the controller is connected to the temperature sensor 8 to obtain the temperature of the stator liner 5, and calculates the temperature difference of the stator liner 5 according to the average temperature of the stator liner 5 per unit time. If the temperature difference is greater than a preset difference, it is determined that the operating stability of the rotor 1 does not meet the requirements, and the rotation speed of the rotor 1 is adjusted.

[0055] Specifically, the speed adjustment amplitude of the rotor 1 is positively correlated with the temperature difference.

[0056] Specifically, the temperature difference is the difference between the temperature of the stator liner 5 and the average temperature of the stator liner 5 per unit time.

[0057] Specifically, the general value range of the preset difference amount is [4°C, 6°C].

[0058] Preferably, a preferred embodiment of the preset difference amount is 5°C.

[0059] During implementation, when the difference between the temperature difference and the preset difference is within 1°C, the rotation speed of rotor 1 increases to 1.2 times the original; when the difference between the temperature difference and the preset difference exceeds 1°C, the rotation speed of rotor 1 increases by 8 rpm for every 1°C increase. For example, when the temperature difference is 7°C and the current rotation speed of rotor 1 is 120 rpm, the rotation speed of rotor 1 increases to 120 rpm×1.2+8 rpm=152 rpm.

[0060] During implementation, the rotation speed of the rotor 1 is adjusted, and impurities in the cooling oil accumulate in the cooling channel, resulting in frictional heat generation in the stator liner 5 and reduced operating stability of the rotor 1. By initially adjusting the rotation speed of the rotor 1 to reduce the accumulation of impurities in the cooling channel, the operating stability of the rotor 1 is improved, and the heat dissipation performance of the stator is further increased.

[0061] Specifically, the controller is connected to the temperature sensor 8 to determine that the friction degree between the stator liner 5 and the rotor 1 does not meet the requirements if the temperature reduction rate of the stator liner 5 is greater than a preset rate after the single-screw pump stops working.

[0062] Specifically, the temperature reduction rate is a ratio of a difference between the temperature of the stator liner 5 at the start time of the unit time and the temperature of the stator liner 5 at the end time of the unit time and the unit time.

[0063] Specifically, the general value range of the preset rate is [4°C / min, 6°C / min].

[0064] In practice, a preferred embodiment of the preset rate is 5°C / min.

[0065] In implementation, the system of the present invention sets a preset rate. Since after the single-screw pump stops working, if there is wear that causes local temperature rise and thus a fast temperature reduction rate, it is determined that there is abnormal wear between the stator sleeve 5 and the rotor 1. By determining whether the degree of friction between the stator sleeve 5 and the rotor 1 meets the requirements, the working performance of the single-screw pump is improved.

[0066] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A self-cooling single screw pump for oil production, characterized in that: include: The oil extraction and conveying mechanism comprises a rotor which rotates in the oil conveying direction to provide oil suction power and a stator which is connected to the rotor to form an oil closed conveying channel with the rotor, wherein the stator comprises a stator bushing which collects oil by cooperating with the rotor and a stator outer tube which is connected to the stator bushing to support the stator bushing; A self-cooling mechanism is connected to the stator and cools the oil circulating inside the stator bushing by absorbing the heat of the stator. The self-cooling mechanism includes a first cooling channel and a second cooling channel connected to the stator bushing and cooperating with each other to provide a cooling circulation space for the oil. The relative spatial configuration of the first cooling channel and the second cooling channel is a double helix structure.

2. The self-cooling single screw pump for oil production according to claim 1, characterized in that: The pitches of the first cooling channel and the second cooling channel are equal.

3. The self-cooling single screw pump for oil production according to claim 2, characterized in that: A pitch of the first cooling channel or the second cooling channel is twice a pitch of the stator bushing.

4. The self-cooling single screw pump for oil production according to claim 3, characterized in that: The midpoints of the first cooling channel and the second cooling channel are at the same distance in the cross section along the oil inlet direction.

5. The self-cooling oil production single screw pump according to claim 4, characterized in that: The first cooling channel includes a plurality of external communication holes and an internal communication hole provided on the suction end of the stator for sucking the cooling oil; The second cooling channel has the same internal structure as the first cooling channel.

6. The self-cooling oil production single screw pump according to claim 5, characterized in that: The single external communication hole is arranged on the stator outer tube to discharge the cooling oil to the area outside the stator outer tube.

7. The self-cooling single screw pump for oil production according to claim 6, characterized in that: The number of the external communication holes is positively correlated with the pitch of the stator bushing.

8. The self-cooling single screw pump for oil production according to claim 7, characterized in that: The projection distances of the distances between each two adjacent external communication holes in the first cooling channel and the second cooling channel on the stator center line are the same.

9. The self-cooling oil production single screw pump according to claim 8, characterized in that: The rotor is also used for the stator to suck the cooling oil into the oil closed delivery channel when the cooling oil flows from the external communication port into the cooling channel and flows out through the internal communication port to merge with the oil in the oil suction area of ​​the stator.

10. The self-cooling oil production single screw pump according to claim 9, characterized in that: The rotor circulates and squeezes the cooling channel during the meshing process with the stator so that the cooling oil is transported from the outer communication hole to the inner communication hole.

11. The self-cooling oil production single screw pump according to claim 10, characterized in that: The rotor and the stator are periodically rotated and meshed so that oil is repeatedly sucked in and discharged through the first cooling channel and the second cooling channel to dissipate heat from the stator.

12. The self-cooling oil production single screw pump according to claim 11, characterized in that: The stator is also used to form a vacuum space between the outer wall of the rotor and the inner wall of the stator bushing during the rotation of the rotor to allow the oil to flow in the oil delivery direction.

13. The self-cooling single screw pump for oil production according to claim 12, characterized in that: The material of the stator bushing is rubber.

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