A sand removal and desanding device for oil wellheads

Abstract

This invention discloses a sand removal and discharge device for oil wellheads, relating to the technical field of sand removal. The device includes a top box and a bottom box fixed to the bottom of the top box, an oil inlet fixed to and communicating with the top box, a tapered bottom of the bottom box with an oil outlet fixed to and communicating with it, a partition fixed inside the top box dividing the top box into a drive chamber and a primary separation chamber. A primary separation mechanism is installed in the primary separation chamber and connected to a drive mechanism installed in the drive chamber. A secondary separation mechanism is installed inside the bottom box and cooperates with the primary separation mechanism. Dual-stage synergistic filtration is achieved through the primary and secondary filtration mechanisms. In the primary filtration mechanism, a scraper cleans the sand and gravel, simultaneously causing the sand to move towards the sand discharge assembly, which then discharges the sand.

Description

Technical Field

[0001] This invention relates to the field of sand removal technology, specifically to a sand removal and discharge device for oil wellheads. Background Technology

[0002] Petroleum, a viscous, dark brown liquid, is often referred to as the "blood of industry." Petroleum resources are stored in certain areas of the Earth's upper crust. Its main components are a mixture of various alkanes, cycloalkanes, and aromatic hydrocarbons. It is also one of the primary targets of geological exploration.

[0003] After the oil is extracted, it contains a certain amount of sand, which needs to be removed when it is discharged from the inlet to avoid the sand particles in the oil causing wear and jamming to subsequent processing equipment.

[0004] Regarding sand removal in oil, a search revealed a sand filter for oil wells with announcement number CN207673325U. This sand filter for oil wells utilizes flow dynamics. However, oil is a viscous liquid, and filtration relies on flow dynamics and the pressure of oil ejection to drive the oil flow, resulting in low filtration efficiency.

[0005] Furthermore, since it filters sand particles from oil, and the sand particles are relatively small in diameter, the filter pores in the filter structure are also relatively small. Therefore, the fluidity of oil is inevitably less than that of water, and its filtration efficiency will decrease significantly. Although the oil is under a certain pressure when it is discharged from the inlet, with a pressure of 2.5-3.5 bar, when this pressure is applied to the entire chamber, the flow rate of the oil as it is driven through the filter components does not increase significantly.

[0006] Secondly, the equipment directly extracts oil and sand particles through the pump body, which will extract some oil along with it. This oil is mixed with a large amount of sand particles, and can only be separated again or discarded, which does not conform to the concept of energy-saving and low-carbon oil extraction. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a sand removal and discharge device for oil wellheads, which solves the problem of insufficient pressure during oil filtration.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a sand removal and discharge device for oil wellheads, comprising:

[0009] Top box and bottom box fixed to the bottom of the top box;

[0010] An oil inlet is fixed to and communicates with the top box, and the bottom of the bottom box is tapered, with an oil outlet fixed to and communicating with it.

[0011] A partition is fixed inside the top box, which divides the top box into a drive chamber and a primary separation chamber. A primary separation mechanism is installed in the primary separation chamber, and the primary separation mechanism is connected to the drive mechanism installed in the drive chamber.

[0012] The secondary separation mechanism is installed inside the base box and cooperates with the primary separation mechanism;

[0013] The primary and secondary separation mechanisms are driven to work synchronously by the drive mechanism. The oil is processed sequentially by the primary and secondary separation mechanisms, and the separated sand is discharged at the same time.

[0014] Furthermore, the primary separation mechanism includes a central shaft tube that passes through and is rotatably and sealingly connected to the partition plate. A flow-limiting plate is coaxially fixed on the central shaft tube, and flow-limiting holes are formed on the flow-limiting plate. Multiple scrapers are fixed at equal intervals around the bottom circumference of the flow-limiting holes.

[0015] The scraper is arc-shaped, and an inclined part is provided at the bottom of the inner side of the arc. The scraper cooperates with the filter plate opened at the bottom of the top box.

[0016] The scraper is also fixed to the central tube, and the bottom of the central tube is provided with a sand inlet at the fixing point of the two scrapers;

[0017] A sand removal assembly is installed inside the central tube. The sand removal assembly is connected to the drive mechanism and the secondary separation mechanism, and the central tube is connected to the drive mechanism.

[0018] Furthermore, multiple mixing plates are fixed equidistantly around the circumference of the central tube, and multiple through slots are formed on the mixing plates;

[0019] The mixing plate is located within the primary separation chamber.

[0020] Furthermore, the sand removal assembly includes a top sealing plate fixed to the top of the central tube, a central shaft is provided inside the central tube, the central shaft passes through the top box and the top sealing plate and is rotatably connected to them in a sealed manner, the central shaft connects the drive mechanism and the secondary separation mechanism, and a sand discharge component for discharging sand is installed at the top of the central shaft;

[0021] A first spiral conveying blade and a first actuating plate are coaxially fixed on the central shaft, with the first actuating plate located at the top of the first spiral conveying blade;

[0022] A sand collection pipe is coaxially fixed at the bottom of the top box. The sand collection pipe is inserted into the bottom of the central shaft tube and is sealed and rotatably connected to it. A sand collection port is opened on one side of the sand collection pipe, and the sand collection port cooperates with the sand inlet.

[0023] Furthermore, the sand discharge component includes a flow divider box that is rotatably and sealed on the central shaft tube. The central shaft tube has multiple sand discharge holes equidistantly spaced around its circumference, and the flow divider box and the central shaft tube are connected through the sand discharge holes.

[0024] A sand-collecting pipe is fixed to the outside of the top box, and a sand discharge port connected to the sand-collecting pipe is fixed to the sand-collecting pipe. Multiple sand discharge pipes connected to the sand-collecting pipe are fixed to the inner wall of the sand-collecting pipe. The sand discharge pipes pass through the top box and are fixed to the top box. The other end of the sand discharge pipe is fixedly connected to the distribution box and is connected to it.

[0025] The sand discharge pipe is located inside the drive cavity.

[0026] Furthermore, the drive mechanism includes a support member fixed to the inner wall of the top box and rotatably connected to the central shaft, and a bracket is fixed on the support member;

[0027] A drive gear is coaxially fixed on the central shaft, and multiple driven gears that mesh with the drive gear are rotatably mounted on the bracket. The driven gears mesh with a toothed ring fixed to the inner wall of the central shaft tube.

[0028] A motor is fixed to the top of the top box, and the motor's transmission shaft passes through the top box and is coaxially fixed with the central shaft.

[0029] Furthermore, the secondary separation mechanism includes a flow-concentrating element fixed to the bottom of the top box;

[0030] The current-gathering component includes a tapered upper part and an integrally formed lower part at the bottom of the upper part. The lower part is cylindrical and has fine filter holes. The central shaft is inserted into the lower part and is coaxial with it. A second spiral conveying blade is provided in the lower part of the current-gathering component and is fixed coaxially with it.

[0031] A return flow assembly is installed at the bottom of the flow collector, and the return flow assembly is connected to the central shaft.

[0032] Furthermore, the pitch of the second spiral conveying blade gradually decreases from top to bottom, and the spiral direction of the second spiral conveying blade is opposite to that of the first spiral conveying blade.

[0033] Furthermore, the reflux assembly includes a reflux pipe fixed to the bottom of the current collector, and a lower sand hole is provided on the reflux pipe. The reflux pipe and the current collector are connected through the lower sand hole.

[0034] The central shaft passes through the return pipe and is rotatably connected to it. Multiple second-stage actuating plates are coaxially fixed on the central shaft, and the second-stage actuating plates are located inside the return pipe.

[0035] The other end of the reflux pipe is connected to the primary separation chamber.

[0036] Furthermore, the arc of the scraper is the same as that of the Archimedean spiral.

[0037] The present invention has the following beneficial effects:

[0038] 1. The wellhead sand removal and discharge device of this oil well achieves dual-stage synergistic filtration through a primary filtration mechanism and a secondary filtration mechanism;

[0039] In the primary filtration mechanism, a scraper cleans the sand and gravel, and at the same time, moves the sand toward the sand discharge assembly, which then discharges the sand.

[0040] At the same time, while cleaning sand particles, the scraper can apply a certain amount of pressure to the oil on the filter plate (the pressure of the scraper + the pressure when the oil is sprayed out + the downward flow of oil due to gravity), which improves the filtration efficiency of the oil and has a dynamic self-cleaning ability.

[0041] The secondary filtration mechanism compresses the oil using a tapered second spiral conveyor blade, and with finer filter holes (fine filter holes), it achieves finer secondary filtration. The filtered sand can be returned to the primary filtration mechanism via a return component. As a result, this invention can discharge sand particles without stopping the machine.

[0042] Second, the sand removal and discharge device at the wellhead of this oil well achieves secondary separation through the reflux component, and then returns the sand particles and part of the oil to the primary separation component. Compared with the existing technology that directly extracts oil and sand particles, this invention can significantly reduce oil waste, reduce extraction costs, and help oil extraction in a low-carbon and energy-saving manner.

[0043] Third, the sand removal and discharge device at the wellhead of this oil well is driven by a planetary gear set of the drive mechanism. Through a three-stage transmission structure of sun gear-planet gear-gear ring, the high speed of the central shaft and the high torque of the central tube are synchronously rotated in opposite directions. This not only meets the high-speed rotation requirements of the spiral conveyor blades, but also provides high torque for the central tube and scraper.

[0044] The unique phase difference design creates a "scissor effect" in sand conveying, which, combined with the evenly distributed planetary gears to eliminate off-center loading, controls the vibration amplitude within ±0.05mm, thereby reducing the probability of oil foam formation.

[0045] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0047] Figure 2 for Figure 1 A structural diagram from another direction;

[0048] Figure 3 for Figure 2 A sectional view;

[0049] Figure 4 This is a schematic diagram of the internal structure of the top box and bottom box in this invention;

[0050] Figure 5 for Figure 4 Another structural diagram from another angle;

[0051] Figure 6 for Figure 4 Exploded structural diagram;

[0052] Figure 7 for Figure 6 A schematic diagram of the mechanism in another direction;

[0053] Figure 8 for Figure 7 Enlarged view of the local structure at point A;

[0054] Figure 9 This is a cross-sectional view of the central tube and the current-collecting element in this invention;

[0055] Figure 10 for Figure 9 Another structural diagram from another angle;

[0056] Figure 11 This is a schematic diagram of the reflux pipe in this invention;

[0057] Figure 12 This is a schematic diagram of the connection structure between the central shaft tube and the sand collection tube in this invention;

[0058] Figure 13 This is a schematic diagram of the scraper shape in this invention.

[0059] In the diagram: 1. Top box; 101. Oil inlet; 102. Support leg; 103. Filter plate; 2. Sand collection pipe; 201. Sand discharge port; 202. Sand discharge pipe; 203. Diverter box; 204. Sand discharge hole; 3. Bottom box; 301. Oil outlet; 4. Return pipe; 401. Flow collector; 402. Fine filter hole; 403. Sand discharge hole; 5. Motor; 501. Bracket; 502. Drive gear; 503. Driven gear; 504. Gear ring section; 505. Top sealing plate; 6. Central shaft tube; 601. Support component; 602. Partition plate; 603. Through groove; 604. Flow limiting plate; 605. Mixing plate; 606. Flow limiting hole; 607. Scraper; 608. Inclined part; 7. Central shaft rod; 701. No. 1 actuating plate; 702. No. 1 spiral conveyor blade; 703. No. 2 spiral conveyor blade; 704. No. 2 actuating plate; 8. Sand collection pipe; 801. Sand collection port; 802. Sand inlet. Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0062] The following is based on Figures 1-13 This invention describes a sand removal and discharge device for oil wellheads provided in an embodiment of the present invention.

[0063] like Figures 1-13 As shown, an embodiment of the present invention provides a sand removal and discharge device for oil wellheads, including a top box 1 and a bottom box 3 fixed to the bottom of the top box 1; a support leg 102 is fixed to the bottom of the bottom box 3;

[0064] An oil inlet 101 is fixed to and communicates with the top box 1, and the bottom of the bottom box 3 is tapered, with an oil outlet 301 fixed to and communicating with the bottom of the bottom box 3.

[0065] A partition 602 fixed inside the top box 1 divides the top box 1 into a drive chamber and a primary separation chamber. A primary separation mechanism is installed in the primary separation chamber, and the primary separation mechanism is connected to the drive mechanism installed in the drive chamber.

[0066] A secondary separation mechanism installed inside the base box 3 and cooperating with the primary separation mechanism;

[0067] The primary and secondary separation mechanisms are driven to work synchronously by the drive mechanism. The oil is processed sequentially by the primary and secondary separation mechanisms, and the separated sand is discharged at the same time.

[0068] In this embodiment of the invention, when the drive mechanism is working, it simultaneously drives the primary separation mechanism and the secondary separation mechanism.

[0069] Before construction, the oil well outlet is fixed and connected to the oil inlet 101 through a pipe fitting, so that oil is transported to the top box 1 through the oil inlet 101, and at the same time the oil outlet 301 is connected to the oil collection equipment through a pipe fitting.

[0070] The oil entering the top tank 1 undergoes initial separation treatment through a primary separation mechanism, causing sand to remain in the top tank 1. The oil then enters the bottom tank 3, where it undergoes secondary separation treatment through a secondary separation mechanism.

[0071] The primary separation unit can discharge the separated sand to the outside of the top box 1 without stopping the machine and disassembling it. The sand separated by the secondary separation unit will be transported to the primary separation unit and discharged through the sand discharge structure of the primary separation unit.

[0072] The oil separated by the secondary separation mechanism is transported to the oil collection equipment through the oil outlet 301 and pipe fittings.

[0073] The primary separation mechanism includes a central shaft tube 6 that passes through and is rotatably and sealed to the partition plate 602. A flow limiting plate 604 is coaxially fixed on the central shaft tube 6. A flow limiting hole 606 is formed on the flow limiting plate 604. Multiple scrapers 607 are fixed at equal intervals around the bottom circumference of the flow limiting hole 606.

[0074] The scraper 607 is arc-shaped, and an inclined part 608 is provided at the bottom of its inner side. The scraper 607 cooperates with the filter plate 103 opened at the bottom of the top box 1.

[0075] The scraper 607 is also fixed to the central tube 6, and the bottom of the central tube 6 is provided with sand inlet 802 at the fixing points of the two scrapers 607;

[0076] A sand removal assembly is installed inside the central tube 6. The sand removal assembly is connected to the drive mechanism and the secondary separation mechanism, and the central tube 6 is connected to the drive mechanism.

[0077] The arc of the scraper 607 is the same as that of the Archimedean spiral.

[0078] In embodiments of the present invention, such as Figure 13 As shown, the Archimedes spiral will drive the material to move centripetally when it rotates. In this embodiment, the arc of the scraper 607 is set to be the same as the arc of the Archimedes spiral, which has the effect of centripetal motion without material when the Archimedes spiral rotates.

[0079] When the drive mechanism is working, it drives the central shaft tube 6 to rotate and simultaneously drives the sand removal assembly to work; when the central shaft tube 6 rotates, it synchronously drives the flow restriction hole 606 and the scraper 607 to rotate.

[0080] When the oil enters the top box 1, it is actually in the primary separation chamber. The oil flows naturally to the bottom of the top box 1 and is filtered by the filter plate 103 at the bottom of the top box 1. During filtration, the oil enters the bottom box 3 through the filter plate 103, while the sand remains in the primary separation chamber.

[0081] Petroleum has a certain viscosity, resulting in relatively low filtration efficiency through filter plate 103. The solution of the present invention is to place the petroleum on the flow limiting plate 604 after it enters the primary separation chamber, and limit the falling speed of the petroleum by the mixing plate 605 set on the flow limiting plate 604, so that the petroleum will not all accumulate on the filter plate 103.

[0082] The oil moving onto the filter plate 103 has a certain viscosity and contains sand, resulting in poor efficiency when passing through the filter plate 103. The solution of the present invention is to drive the scraper 607 to rotate. When the scraper 607 rotates, it scrapes the surface of the filter plate 103 to remove the sand that is clogging the filter plate 103. Furthermore, since the bottom of the scraper 607 is provided with an inclined portion 608, when the inclined portion 608 rotates, it applies a compressive force to the oil, thereby increasing the filtration efficiency of the oil.

[0083] It should be noted that the filter plate 103 is not installed at the center of the bottom of the top box 1. Figure 9 As shown.

[0084] Multiple mixing plates 605 are fixed equidistantly around the central tube 6, and multiple through slots 603 are provided on the mixing plates 605.

[0085] The mixing plate 605 is located inside the primary separation chamber.

[0086] In this embodiment of the invention, when the central shaft tube 6 rotates, it drives the mixing plate 605 to rotate synchronously, so as to stir the oil in the primary separation chamber through the mixing plate 605, so as to mix the sand and oil evenly, so as to avoid sand agglomeration, which would cause the oil output to be intermittent during separation, and thus make the oil output of this device inconsistent when separating sand.

[0087] The sand removal assembly includes a top sealing plate 505 fixed to the top of the central shaft tube 6. A central shaft rod 7 is provided inside the central shaft tube 6. The central shaft rod 7 passes through the top box 1 and the top sealing plate 505 and is rotatably connected to them in a sealed manner. The central shaft rod 7 is connected to the drive mechanism and the secondary separation mechanism. A sand discharge component for discharging sand is installed on the top of the central shaft rod 7.

[0088] A first spiral conveying blade 702 and a first actuating plate 701 are coaxially fixed on the central shaft 7, and the first actuating plate 701 is located at the top of the first spiral conveying blade 702.

[0089] A sand collection pipe 8 is coaxially fixed at the bottom of the top box 1. The sand collection pipe 8 is inserted into the bottom of the central shaft pipe 6 and is sealed and rotatably connected to it. A sand collection port 801 is opened on one side of the sand collection pipe 8, and the sand collection port 801 cooperates with the sand inlet 802.

[0090] In this embodiment of the invention, when the drive mechanism is working, it drives the central shaft 7 to rotate, and when the central shaft 7 rotates, it synchronously drives the first actuating plate 701 and the first spiral conveying blade 702 to rotate.

[0091] When the central shaft tube 6 rotates, the scraper 607 drives the separated sand towards the sand inlet 802. The sand will enter the sand collection tube 8 when the sand inlet 802 and the sand collection port 801 overlap. The rotating first spiral conveyor blade 702 causes the sand in the sand collection tube 8 and the central shaft tube 6 to move towards the top of the central shaft tube 6, and finally the sand is discharged through the sand discharge component.

[0092] As an alternative embodiment, a first filter hole is provided on the central shaft 7, and a second filter hole is provided on the first spiral conveying blade 702. When the sand is conveyed from bottom to top by the rotation of the first spiral conveying blade 702, a small amount of oil will inevitably be conveyed along with it. During the conveying process, the oil in the conveyed sand can be filtered again through the first and second filter holes, so that the sand stays in the central shaft 7 and the oil enters the top box 1.

[0093] This solution is effective when used with low-viscosity oil, but not so effective when the oil viscosity is high. Therefore, this embodiment can be selected according to the actual situation when used.

[0094] The sand discharge component includes a diversion box 203 that is rotatably and sealed on the central shaft tube 6. The central shaft tube 6 has a plurality of sand discharge holes 204 equidistantly opened on its circumference. The diversion box 203 and the central shaft tube 6 are connected through the sand discharge holes 204.

[0095] A sand-collecting pipe 2 is fixed to the outside of the top box 1. A sand discharge port 201 connected to the sand-collecting pipe 2 is fixed to the sand-collecting pipe 2. Multiple sand discharge pipes 202 connected to the sand-collecting pipe 2 are fixed to the inner wall of the sand-collecting pipe 2. The sand discharge pipes 202 pass through the top box 1 and are fixed to the top box 1. The other end of the sand discharge pipe 202 is fixedly connected to the diversion box 203 and is connected to it.

[0096] The sand discharge pipe 202 is located inside the drive cavity.

[0097] In this embodiment of the invention, after the sand is conveyed to the top by the rotation of the No. 1 spiral conveying blade 702, the No. 1 actuating plate 701 drives the sand to enter the diversion box 203 through the sand discharge hole 204. Then the sand in the diversion box 203 moves to the sand collection pipe 2 through the sand discharge pipe 202 and is discharged through the sand discharge port 201.

[0098] The function of the diversion box 203 is that when the first spiral conveying blade 702 rotates, sand can be discharged into the diversion box 203. The diversion box 203 transports the sand through the sand discharge pipe 202 to the sand collection pipe 2, and then discharges it at the designated position through the sand discharge port 201.

[0099] The drive mechanism includes a support member 601 fixed to the inner wall of the top box 1 and rotatably connected to the central shaft 7, and a bracket 501 is fixed on the support member 601;

[0100] A drive gear 502 is coaxially fixed on the central shaft 7, and a plurality of driven gears 503 that mesh with the drive gear 502 are rotatably mounted on the bracket 501. The driven gears 503 mesh with the toothed ring portion 504 fixed on the inner wall of the central shaft tube 6.

[0101] A motor 5 is fixed to the top of the top box 1, and the conveying shaft of the motor 5 passes through the top box 1 and is coaxially fixed with the central shaft 7.

[0102] In this embodiment of the invention, when the motor 5 is working, it drives the central shaft 7 to rotate through its output shaft. When the central shaft 7 rotates, it drives the driving gear 502 to rotate coaxially. When the driving gear 502 rotates, it drives the driven gear 503 to rotate through meshing with the driven gear 503. When the driven gear 503 rotates, it drives the gear ring part 504 to rotate through meshing with the gear ring part 504.

[0103] For example, the central shaft 7 and the driving gear 502 rotate clockwise, while the driven gear 503 meshing with the driving gear 502 rotates counterclockwise. When the driven gear 503 rotates counterclockwise, the gear ring 504 and the central shaft tube 6 also rotate counterclockwise. (This description of the rotation direction is only for the purpose of explaining the principle and is not intended to limit the features of this invention.) This makes the rotation directions of the central shaft 7 and the central shaft tube 6 opposite, and the rotation speed of the central shaft 7 is greater than that of the central shaft tube 6.

[0104] Because the rotation of the central shaft 7 and the first spiral conveying blade 702 to achieve bottom-to-top conveying requires the first spiral conveying blade 702 to have a certain rotational speed, while the rotation of the central shaft 7 does not require high conveying speed but requires a certain torque, this driving method can effectively achieve high rotational speed of the central shaft 7 and high torque of the central shaft tube 6. Furthermore, the cooperation between the first spiral conveying blade 702 and the inner wall of the central shaft tube 6 requires that the two rotate asynchronously and in opposite directions, thus the drive and transmission in this embodiment are perfectly matched.

[0105] The secondary separation mechanism includes a flow-concentrating element 401 fixed to the bottom of the top box 1;

[0106] The flow-concentrating component 401 includes a tapered upper part and an integrally formed lower part at the bottom of the upper part. The lower part is cylindrical and has fine filter holes 402. The central shaft 7 is inserted into the lower part and is coaxially arranged with it. A second spiral conveying blade 703 is provided in the lower part of the flow-concentrating component 401 and is fixed coaxially with the central shaft 7.

[0107] The bottom of the flow-gathering component 401 is equipped with a return flow assembly, which is connected to the central shaft 7.

[0108] In this embodiment of the invention, the oil filtered by the filter plate 103 is collected and limited by the top of the concentrator 401, causing the oil to move toward the bottom of the concentrator 401 until it reaches the second spiral conveying blade 703.

[0109] When the central shaft 7 rotates, it drives the second spiral conveying blade 703 to rotate. When the second spiral conveying blade 703 rotates, it conveys the oil at the top of the blade towards the ground. During the conveying process, since the second spiral conveying blade 703 is designed with a variable diameter thread, it exerts a certain amount of pressure on the actual oil, forcing the oil to be discharged through the fine filter hole 402 and move into the bottom box 3. Then, it is discharged in a directional manner through the oil outlet 301 at the bottom of the bottom box 3.

[0110] It should be noted that the spiral direction of the second spiral conveying blade 703 is opposite to that of the first spiral conveying blade 702, so that when the central shaft 7 rotates, the first spiral conveying blade 702 moves from bottom to top, and the second spiral conveying blade 703 moves from top to bottom.

[0111] The pitch of the second spiral conveying blade 703 gradually decreases from top to bottom, and the spiral direction of the second spiral conveying blade 703 is opposite to that of the first spiral conveying blade 702.

[0112] In an optional embodiment: the reflux assembly includes a reflux pipe 4 fixed to the bottom of the current collector 401, the reflux pipe 4 having a lower sand hole 403, and the reflux pipe 4 and the current collector 401 being connected through the lower sand hole 403;

[0113] The central shaft 7 passes through the return pipe 4 and is rotatably connected to it. Multiple second-stage actuating plates 704 are coaxially fixed on the central shaft 7, and the second-stage actuating plates 704 are located inside the return pipe 4.

[0114] The other end of the return pipe 4 is connected to the primary separation chamber.

[0115] In this embodiment of the invention, after the oil is squeezed by the rotation of the second spiral conveying blade 703, it will be discharged through the fine filter hole 402, while the sand will enter the return pipe 4 through the lower sand hole 403. When the central shaft 7 rotates, it drives the second actuating plate 704 to rotate. The rotation of the second actuating plate 704 drives the sand in the return pipe 4 to flow back to the primary separation chamber.

[0116] In the process of squeezing the oil through the second spiral conveying blade 703, although most of the oil will be squeezed out through the fine filter hole 402, some oil will still enter the return pipe 4, and this part of the oil is the medium for sand return.

[0117] In summary, this oil separation system adopts a vertical layout structure of top tank 1 and bottom tank 3, and synchronously controls the coordinated operation of the primary separation mechanism (inside the top tank) and the secondary separation mechanism (inside the bottom tank) through a drive mechanism. Key features include modular design: the top tank 1 and bottom tank 3 are connected, and the bottom tank 3 has an oil outlet 301 at its conical bottom for directional oil discharge; a dual-stage filtration mechanism: the primary separation chamber achieves coarse filtration through filter plate 103, and the secondary separation mechanism completes fine filtration through fine filter holes 402; and continuous sand discharge function: the automatic collection and discharge of separated sand is achieved through the counter-rotation of the central shaft tube 6 and the central shaft rod 7. The core of the primary separation mechanism's motion principle lies in the dynamic coordination of the flow restrictor 604 and the scraper 607.

[0118] When the central shaft tube 6 rotates, the Archimedes spiral-shaped scraper 607 scrapes along the surface of the filter plate 103, and its inclined part 608 applies radial extrusion force to the oil, increasing the filtration rate of viscous oil by more than 40%. The mixing plate 605 forms turbulence during rotation through the through groove 603 structure, preventing sand particles from depositing. The sand particles move towards the center along the filter plate 103 and enter the sand collection pipe 8 through the sand inlet 802. The central shaft 7 pushes the sand particles upward through the first spiral conveying blade 702. During this process, the first filter hole achieves secondary separation of sand and oil. During sand discharge, the diversion box 203 distributes the sand particles to the sand collection pipe 2, and finally discharges them through the sand discharge port 201.

[0119] The secondary separation mechanism achieves efficient separation through the variable-diameter compression design of the flow-converging element 401. Its core lies in the second spiral conveying blade 703, which employs a reverse spiral direction (opposite to the first spiral conveying blade 702) and a gradually narrowing flow channel structure with decreasing pitch from top to bottom. When oil passes through the fine filter holes 402, the resulting 0.3MPa pressure gradient significantly improves separation purity, while the second actuating plate 704 ensures that residual sand particles are pushed back into the primary separation chamber to form a closed-loop process. The drive mechanism achieves precise control through a gear set (driving gear 502 / driven gear 503 / gear ring 504): the high-speed rotation of the central shaft 7 drives the spiral blades, while the central shaft tube 6 maintains stable scraping by the scraper 607 at low speed and high torque. This dual-speed coordination ensures that sand particle conveying and filter plate 103 cleaning are completed synchronously.

[0120] The system's collaborative workflow begins with oil entering the primary separation chamber through inlet 101, where a flow restrictor 604 controls the flow rate to prevent overload. In the initial separation stage, scraper 607 clears blockages from filter plate 103 using an Archimedean spiral trajectory, while mixing plate 605 maintains uniform mixing of oil and sand through channels 603. In the sand recovery stage, the first spiral conveyor blade 702, driven by the central shaft 7, pushes sand particles upwards, distributing them via a distribution box 203 to the sand collection pipe 2 for centralized treatment. Simultaneously, the second spiral conveyor blade 703 compresses and squeezes the remaining oil through a variable diameter mechanism. Finally, the purified oil is discharged from outlet 301, forming a continuous closed-loop operation. This process achieves a sand removal rate of 98% through two-stage separation. The collaborative design of scraper 607 and spiral blades enables real-time self-cleaning of filter plate 103, while the continuous sand discharge mechanism completely avoids downtime for sand cleaning, making it particularly suitable for continuous oilfield operations.

[0121] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0122] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A sand removal and discharge device for oil wellheads, characterized in that, include: Top box (1) and bottom box (3) fixed to the bottom of the top box (1); An oil inlet (101) is fixed to and connected to the top box (1). The bottom of the bottom box (3) is cone-shaped, and an oil outlet (301) connected to it is fixed at the bottom of the bottom box (3). The partition (602) is fixed inside the top box (1). The partition (602) divides the top box (1) into a drive chamber and a first-level separation chamber. A first-level separation mechanism is installed in the first-level separation chamber. The first-level separation mechanism is connected to the drive mechanism installed in the drive chamber. The secondary separation mechanism is installed in the bottom box (3) and cooperates with the primary separation mechanism; The primary and secondary separation mechanisms are driven by a drive mechanism to work synchronously, and the oil is processed sequentially by the primary and secondary separation mechanisms, while the separated sand is discharged at the same time. The primary separation mechanism includes a central tube (6) that passes through and is rotatably and sealed to the partition (602). A flow limiting plate (604) is coaxially fixed on the central tube (6). A flow limiting hole (606) is formed on the flow limiting plate (604). Multiple scrapers (607) are fixed at equal intervals around the bottom circumference of the flow limiting hole (606). The scraper (607) is arranged in an arc shape, and an inclined part (608) is provided at the bottom of the inner side of the arc. The scraper (607) cooperates with the filter plate (103) opened at the bottom of the top box (1). The scraper (607) is also fixed to the central tube (6), and the bottom of the central tube (6) is provided with a sand inlet (802) at the fixing point of the two scrapers (607). A sand removal assembly is installed inside the central tube (6). The sand removal assembly is connected to the drive mechanism and the secondary separation mechanism, and the central tube (6) is connected to the drive mechanism. The sand removal assembly includes a top sealing plate (505) fixed to the top of the central tube (6), a central shaft (7) is provided inside the central tube (6), the central shaft (7) passes through the top box (1) and the top sealing plate (505) and is rotatably connected to them in a sealed manner, the central shaft (7) connects the drive mechanism and the secondary separation mechanism, and a sand discharge component for discharging sand is installed on the top of the central shaft (7); A first spiral conveying blade (702) and a first actuating plate (701) are coaxially fixed on the central shaft (7), and the first actuating plate (701) is located at the top of the first spiral conveying blade (702); The top box (1) is coaxially fixed with a sand collection pipe (8). The sand collection pipe (8) is inserted into the bottom of the central shaft pipe (6) and sealed and rotated. A sand collection port (801) is opened on one side of the sand collection pipe (8), and the sand collection port (801) cooperates with the sand inlet (802). The sand discharge component includes a flow divider box (203) that is rotatably and sealed on the central shaft tube (6). The central shaft tube (6) has multiple sand discharge holes (204) equidistantly opened on its circumference. The flow divider box (203) and the central shaft tube (6) are connected through the sand discharge holes (204). A sand-collecting pipe (2) is fixed on the outside of the top box (1). A sand discharge port (201) connected to the sand-collecting pipe (2) is fixed on the sand-collecting pipe (2). Multiple sand discharge pipes (202) connected to the sand-collecting pipe (2) are fixed on the inner wall of the sand-collecting pipe (2). The sand discharge pipe (202) passes through the top box (1) and is fixed to the top box (1). The other end of the sand discharge pipe (202) is fixedly connected to the diversion box (203) and connected to it. The sand discharge pipe (202) is located inside the drive cavity; The secondary separation mechanism includes a flow-gathering element (401) fixed to the bottom of the top box (1); The flow-concentrating component (401) includes a cone-shaped upper part and an integrally formed lower part at the bottom of the upper part. The lower part is cylindrical and has fine filter holes (402). The central shaft (7) is inserted into the lower part and is coaxial with it. The lower part of the flow-concentrating component (401) is provided with a second spiral conveying blade (703) that cooperates with it. The second spiral conveying blade (703) is coaxially fixed with the central shaft (7). The bottom of the flow collector (401) is equipped with a return flow assembly, which is connected to the central shaft (7). The reflux assembly includes a reflux pipe (4) fixed to the bottom of the flow collector (401), and a lower sand hole (403) is opened on the reflux pipe (4). The reflux pipe (4) and the flow collector (401) are connected through the lower sand hole (403). The central shaft (7) passes through the return pipe (4) and is rotatably connected to it. Multiple second-stage actuating plates (704) are coaxially fixed on the central shaft (7). The second-stage actuating plates (704) are located inside the return pipe (4). The other end of the reflux pipe (4) is connected to the primary separation chamber.

2. The sand removal and discharge device for oil wellheads according to claim 1, characterized in that, Multiple mixing plates (605) are fixed equidistantly on the circumference of the central tube (6), and multiple through slots (603) are provided on the mixing plates (605). The mixing plate (605) is located inside the primary separation chamber.

3. The sand removal and discharge device for oil wellheads according to claim 2, characterized in that: The drive mechanism includes a support member (601) fixed to the inner wall of the top box (1) and rotatably connected to the central shaft (7), and a bracket (501) is fixed on the support member (601). A drive gear (502) is coaxially fixed on the central shaft (7), and a plurality of driven gears (503) that mesh with the drive gear (502) are rotatably mounted on the bracket (501). The driven gears (503) mesh with the toothed ring portion (504) fixed on the inner wall of the central shaft tube (6). A motor (5) is fixed to the top of the top box (1), and the conveying shaft of the motor (5) passes through the top box (1) and is coaxially fixed with the central shaft (7).

4. The sand removal and discharge device for oil wellheads according to claim 3, characterized in that: The pitch of the second spiral conveying blade (703) gradually decreases from top to bottom, and the spiral direction of the second spiral conveying blade (703) is opposite to that of the first spiral conveying blade (702).

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