A small-diameter oil well downhole allocation device

Abstract

The utility model discloses a kind of small-diameter oil well downhole production allocation device, belong to petroleum exploitation device technical field, including upper joint, outer protective tube, screen pipe, lower joint and center tube, and production allocation device further includes stepped sleeve and drive unit, stepped sleeve is arranged between outer protective tube, screen pipe and center tube, stepped sleeve includes transmission sleeve at upside and functional sleeve at downside, the upper and lower ends of functional sleeve are all provided with radially outward convex sealing protrusion, two sealing protrusions are respectively rotatably connected with outer protective tube inner wall and lower joint inner wall, the side of functional sleeve is provided with first oil inlet, second oil inlet is provided on the side wall of center tube, first oil inlet and second oil inlet are staggered with each other at initial position;Drive unit is arranged on the upside of functional sleeve, and drive unit is used to drive stepped sleeve to rotate;Therefore, the production allocation device disclosed in the utility model can realize continuous accurate adjustment of yield of each layer.

Description

Technical Field

[0001] This utility model belongs to the technical field of oil extraction equipment, specifically relating to a downhole production distribution device for small-diameter oil wells. Background Technology

[0002] In the oilfield development sector, downhole intelligent production allocation devices are key tools for achieving stratified production and precise water control. This is especially true in small-diameter oil wells, where higher demands are placed on the tool's structural dimensions and reliability. Existing intelligent production allocation devices mostly employ motor-driven screw transmission mechanisms to control the opening and closing of nozzles. The screw converts rotary motion into linear motion, pushing the sealing push rod axially to achieve flow channel opening and closing.

[0003] Traditional downhole production control systems for small-diameter oil wells mainly consist of components such as an upper connector, a central tube, an nozzle assembly, a lower connector, an outer protective tube, and a screen tube. The nozzle assembly comprises a motor, coupling, a lead screw, multiple bushings, an anti-rotation push rod, a sealing push rod, and a second sealing ring. The lead screw is connected to the motor's output shaft via a coupling, and the anti-rotation push rod is connected to the lower end of the lead screw. Therefore, when the lead screw rotates, it drives the anti-rotation push rod to move axially. The sealing push rod has multiple pre-machined windows of different sizes along its axial direction. When the sealing push rod moves to different preset positions, a specific window aligns with a fixed nozzle hole on the side wall of the central tube, thus switching to a limited fixed opening degree such as fully open, half open, or fully closed. Therefore, existing production control systems struggle to precisely adjust the production output of each layer. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a small-diameter oil well downhole production distribution device that addresses the shortcomings of the prior art. The device has a simple structure, reasonable design, and strong practicality.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a small-diameter oil well downhole production distribution device, comprising, from bottom to top, an upper connector, an outer protective pipe, a screen pipe, and a lower connector, and further comprising, a central pipe disposed inside the outer protective pipe, the screen pipe, and the lower connector, and further comprising: A stepped sleeve is installed between the outer protective tube, the screen tube, and the central tube. The stepped sleeve includes a transmission sleeve on the upper side and a functional sleeve on the lower side. The outer diameter of the transmission sleeve is smaller than the outer diameter of the functional sleeve. Both ends of the functional sleeve are provided with radially outward-protruding sealing protrusions. The two sealing protrusions are rotatably connected to the inner wall of the outer protective tube and the inner wall of the lower connector, respectively. A first oil inlet is provided on one side of the functional sleeve, which is located between the two sealing protrusions. A second oil inlet is provided on the side wall of the central tube. In the initial position, the first oil inlet and the second oil inlet are staggered. The drive unit is located on the upper side of the functional sleeve and is used to drive the stepped sleeve to rotate.

[0006] Preferably, the drive unit includes a motor bracket disposed on the inner wall of the outer protective tube, a motor mounted on the motor bracket, the output shaft of the motor being vertically downward and connected to a transmission rod via a coupling, a drive gear mounted on the transmission rod, a driven gear meshing with the drive gear mounted on the transmission sleeve, and the motor being connected to the control unit.

[0007] Preferably, the two sealing protrusions at the upper and lower ends are rotatably connected to the outer protective tube and the lower connector via bearings.

[0008] Preferably, the outer protective tube has a pressure guiding hole on its wall, which is located above a sealing protrusion on the upper side. An external pressure sensor for detecting the pressure of the bottom layer is installed inside the pressure guiding hole, and an internal pressure sensor for detecting the internal pressure is installed on the inner wall of the central tube. Both the external pressure sensor and the internal pressure sensor are connected to the control unit.

[0009] Preferably, a moisture content sensor is also provided on the inner wall of the central tube, and the moisture content sensor is connected to the control unit.

[0010] Preferably, a rotary encoder is provided on the transmission sleeve, and the rotary encoder is connected to the control unit.

[0011] Preferably, the functional sleeve and the side wall of the central tube are respectively provided with a first balance hole and a second balance hole. In the initial position, the first balance hole and the second balance hole are aligned and connected to form a balance channel.

[0012] A first sealing ring is provided in the annular gap between the functional sleeve and the central tube, and a second sealing ring is provided in the annular gap between the transmission sleeve and the central tube. The first sealing ring and the second sealing ring are located at both ends of the first oil inlet and the second oil inlet.

[0013] Preferably, the inner walls of the outer protective tube and the lower connector are provided with connecting grooves corresponding to the sealing protrusions, and the two sealing protrusions are rotatably connected to the outer protective tube and the lower connector through the connecting grooves.

[0014] Preferably, a third sealing ring is provided in the connecting groove.

[0015] This utility model has the following advantages compared with the prior art: 1. This utility model discloses a downhole production distribution device for small-diameter oil wells. By using a rotating stepped sleeve as a regulating valve core, the rotation angle of the sleeve is linearly related to the flow area generated by the overlap of the first and second oil inlets. By controlling the rotation angle of the stepped sleeve, continuous control of the flow area can be achieved. Compared with the limited fixed opening of traditional production distribution devices (such as fully open, half open, and fully closed), the production distribution device disclosed in this utility model can achieve continuous and precise adjustment of the production at each layer. 2. This utility model discloses a small-diameter oil well downhole production distribution device. Through the installation of external pressure sensors and internal pressure sensors, a pressure sensing unit is formed that can realize the closed-loop control of each layer. On this basis, the control unit can accurately calculate the real effective pressure difference acting on each layer nozzle. Therefore, the control unit can adjust the production of each layer to the optimal state with the goal of stabilizing the pressure difference, protecting the formation, or optimizing production distribution. 3. This utility model discloses a downhole production distribution device for small-diameter oil wells. By setting a water cut sensor, the control unit can determine the water content of each layer of product. Then, based on the detection result, the control unit can suppress the production of high water cut layers. For layers with low water cut, the production can be controlled by adjusting the overlap area between the first oil inlet and the second oil inlet. Thus, the oil production of a single well can be significantly increased without changing or even reducing the total liquid volume.

[0016] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a small-diameter oil well downhole production distribution device according to the present invention; Figure 2 for Figure 1 Enlarged structural diagram at point A in the middle; Figure 3 for Figure 1 Enlarged structural diagram at point B; Figure 4 for Figure 1 Enlarged structural diagram at point C.

[0018] Explanation of reference numerals in the attached figures: 1. Upper connector; 2. Outer protective tube; 3. Central tube; 3-1. First oil inlet; 3-2. Second oil inlet; 4. Screen tube; 5. Lower connector; 6. Stepped sleeve; 6-1. Transmission sleeve; 6-2. Functional sleeve; 6-3. Sealing protrusion; 6-4. Driven gear; 7. Drive unit; 7-1. Motor bracket; 7-2. Motor; 7-3. Coupling; 7-4. Transmission rod; 7-5. Drive gear; 8. Bearing; 9. Pressure guide hole; 10-1. External pressure sensor; 10-2. Internal pressure sensor; 11. Moisture content sensor; 12. Second sealing ring; 13. Battery unit; 14. First sealing ring; 15. Second sealing ring. Detailed Implementation

[0019] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, this utility model discloses a small-diameter oil well downhole production distribution device, including an upper connector 1, an outer protective pipe 2, a screen pipe 4, a lower connector 5, and a central pipe 3. The upper connector 1, outer protective pipe 2, screen pipe 4, and lower connector 5 are arranged sequentially from bottom to top. The central pipe 3 is located inside the outer protective pipe 2, screen pipe 4, and lower connector 5. The production distribution device also includes a stepped sleeve 6 and a drive unit. The stepped sleeve 6 is located between the outer protective pipe 2, screen pipe 4, and central pipe 3. The stepped sleeve 6 includes a transmission sleeve 6-1 on the upper side and a functional sleeve 6-2 on the lower side. The outer diameter of the transmission sleeve 6-1 is smaller than the outer diameter of the functional sleeve 6-2. Both the upper and lower ends of the functional sleeve 6-2 are provided with radially protruding sealing protrusions. The two sealing protrusions 6-3 are rotatably connected to the inner wall of the outer protective tube 2 and the inner wall of the lower connector 5, respectively. A first oil inlet 3-1 is provided on one side of the functional sleeve 6-2, and the first oil inlet 3-1 is located between the two sealing protrusions 6-3. A second oil inlet 3-2 is provided on the side wall of the central tube 3. In the initial position, the first oil inlet 3-1 and the second oil inlet 3-2 are staggered. The drive unit 7 is located on the upper side of the functional sleeve 6-2. The drive unit is used to drive the stepped sleeve 6 to rotate. Therefore, when the drive unit drives the stepped sleeve 6 to rotate, it can realize the stepless adjustment of the oil inlet channel composed of the first oil inlet 3-1 and the second oil inlet 3-2 from closed to fully open.

[0020] Specifically, to ensure the stable rotation of the stepped sleeve 6 and to improve the reliability of the entire production assembly device; such as Figure 2 As shown, in this embodiment, both the outer protective tube 2 and the lower connector 5 have connecting grooves corresponding to the sealing protrusions 6-3 on their inner walls. The two sealing protrusions 6-3 are rotatably connected to the outer protective tube 2 and the lower connector 5 through the connecting grooves; a third sealing ring 12 is provided in the connecting groove. The connecting grooves on the inner walls of the outer protective tube 2 and the lower connector 5 provide precise axial positioning and circumferential rotation track for the sealing protrusions 6-3; by adding the third sealing ring 12 in the connecting groove, static sealing of high-pressure fluid is achieved on the basis of rotational connection, thereby improving the durability and reliability of the device under harsh well conditions.

[0021] In summary, when the small-diameter oil well downhole production distribution device disclosed in this utility model is in operation, in the initial position, the first oil inlet 3-1 on the functional sleeve 6-2 and the second oil inlet 3-2 on the central pipe 3 are completely misaligned, and the flow channel is blocked. Then, when the layer drive unit drives the stepped sleeve 6 to rotate, as the stepped sleeve rotates, the first oil inlet 3-1 on the functional sleeve and the second oil inlet 3-2 on the side wall of the central pipe 3 generate relative circumferential displacement. When the two are partially or completely aligned, an adjustable flow area is formed, and the fluid from the formation is filtered sequentially through the screen pipe 4 before being further processed. The oil flows through the first inlet 3-1 and the second inlet 3-2 and enters the inner cavity of the central tube 3, achieving controllable production. The downhole production distribution device disclosed in this utility model uses a rotating stepped sleeve 6 as an adjusting valve core. Its rotation angle is linearly related to the flow area generated by the overlap of the first inlet 3-1 and the second inlet 3-2. By controlling the rotation angle of the stepped sleeve, continuous control of the flow area can be achieved. Compared with the limited fixed opening of a few levels (such as fully open, half open, and fully closed) of traditional production distribution devices, the production distribution device disclosed in this utility model can achieve continuous and precise adjustment of the production at each layer.

[0022] Furthermore, to achieve stable rotation of the stepped sleeve 6, this embodiment discloses only one drive unit, which includes a motor bracket 7-1 mounted on the inner wall of the outer protective tube 2. A motor 7-2 is mounted on the motor bracket 7-1. The output shaft of the motor 7-2 is vertically downward and connected to a transmission rod 7-4 via a coupling 7-3. A drive gear 7-5 is mounted on the transmission rod 7-4, and a driven gear 6-4 meshes with the drive gear 7-5 on the transmission sleeve 6-1. The motor 7-2 is connected to a control unit. When the drive unit needs to operate, the control unit sends a command to the motor 7-1. The output shaft of the motor 7-2 drives the transmission rod 7-4 and the drive gear 7-5 to rotate via the coupling 7-3. The drive gear 7-5 meshes with the driven gear 6-4 fixed on the transmission sleeve 6-1, transmitting torque to the stepped sleeve 6, thereby driving it to rotate. Therefore, continuous control of the flow area formed between the first oil inlet on the functional sleeve and the second oil inlet of the central tube can be achieved.

[0023] Furthermore, the two sealing protrusions 6-3 at the upper and lower ends are rotatably connected to the outer protective tube 2 and the lower connector 5 via bearings 8. Specifically, the bearings 8 are fully sealed rolling bearings. By setting bearings 8 between the sealing protrusions 6-3 and the outer protective tube 2 and the lower connector 5, the original sliding friction is converted into rolling friction, which significantly reduces the frictional resistance and required driving torque when the stepped sleeve 6 rotates, making the adjustment action easier and the response more sensitive. At the same time, the bearings 8 provide precise radial positioning and support for the stepped sleeve, ensuring its coaxiality with the central tube. This not only extends the service life of the sealing protrusions 6-3, but also makes the gear meshing smoother, improving the mechanical reliability and adjustment stability of the device in the high-pressure downhole environment.

[0024] Furthermore, in this embodiment, the outer protective tube 2 has a pressure guiding hole 9 on its wall. The pressure guiding hole 9 is located above a sealing protrusion 6-3 on the upper side. An external pressure sensor 10-1 for detecting the bottom layer pressure is installed inside the pressure guiding hole 9. In this embodiment, the pressure guiding hole 9 is positioned above the sealing protrusion 6-3 on the upper side. The purpose is to place the hole and the sensing end of the external pressure sensor 10-1 within a relatively static annular pressure buffer zone isolated by the sealing protrusion. This position effectively avoids the severe pressure disturbance and high-speed sand-containing fluid generated by the throttling zone of the functional sleeve below, ensuring that the external pressure sensor 10-1 can stably and accurately measure the actual formation static pressure. Rather than distorted dynamic pressure; and because an internal pressure sensor 10-2 for detecting internal pressure is also provided on the inner wall of the central tube 3, and both the external pressure sensor 10-1 and the internal pressure sensor 10-2 are connected to the control unit; through the external pressure sensor 10-1 and the internal pressure sensor 10-2, a pressure sensing unit that can realize the closed-loop control of each layer is formed. Specifically, in this embodiment, by acquiring the formation pressure and the internal pressure of the central tube 3 in real time, the control unit can accurately calculate the real effective pressure difference acting on each layer nozzle. Based on this, the control unit can adjust the production of each layer to the optimal state with the goal of stabilizing the pressure difference, protecting the formation, or optimizing production allocation.

[0025] Furthermore, such as Figure 4 As shown, a water cut sensor 11 is also installed on the inner wall of the central pipe 3 disclosed in this embodiment, and the water cut sensor 11 is connected to the control unit. Through the installed water cut sensor 11, the control unit can determine the water content of each layer of product. Then, based on the detection result, the control unit can suppress the production of high water cut layers. For layers with low water cut, the production can be controlled by adjusting the overlap area between the first oil inlet and the second oil inlet. Thus, the oil production of a single well can be significantly increased without changing or even reducing the total liquid volume.

[0026] Furthermore, in order to achieve precise control over the overlap area between the first and second oil inlets, a rotary encoder coaxially mounted on the transmission sleeve 6-1 disclosed in this embodiment is connected to the control unit. Therefore, the rotary encoder can provide real-time and accurate feedback on the rotation angle of the stepped sleeve, enabling the control unit to accurately control the output of each layer.

[0027] Furthermore, such as Figure 3As shown, a first sealing ring 14 is provided in the annular gap between the functional sleeve and the central tube 3, and a second sealing ring 15 is provided in the annular gap between the transmission sleeve 6-1 and the central tube 3. The first sealing ring 14 and the second sealing ring 15 are both located at the two ends of the first oil inlet 3-1 and the second oil inlet 3-2. By setting the first sealing ring 14 and the second sealing ring 15, crude oil can be prevented from leaking from the annular gap, ensuring that the oil enters the central tube 3 only through the first oil inlet 3-1 and the second oil inlet 3-2, avoiding production loss or pressure fluctuation due to leakage, and at the same time ensuring that the drive unit 7 can work normally without interference.

[0028] The functional sleeve 6-2 and the sidewall of the central tube 3 are respectively provided with a first balance hole and a second balance hole. In the initial position, the first balance hole and the second balance hole are aligned and connected to form a balance channel. In the initial position (i.e., the first and second oil inlets are staggered and the nozzle is closed), the first balance hole and the second balance hole are aligned and connected to form a constant pressure balance path independent of the main nozzle channel. This allows the pressure on both sides of the functional sleeve to quickly become consistent even when the well is shut in, thereby significantly reducing the pressure difference borne by the sealing system. When the stepped sleeve 6 is rotated to the open position where the first and second oil inlets overlap, the main nozzle channel has been established. The balance hole may be misaligned and closed, or it may remain connected as an auxiliary balance path.

[0029] In order to ensure normal power supply to the entire production unit, a battery unit is also provided on the upper side of the drive unit 7 disclosed in this embodiment, which is used to supply power to the drive unit 7.

[0030] In summary, this invention uses a drive unit located above the stepped sleeve to drive the stepped sleeve 6 to rotate, thereby controlling the output of each layer by adjusting the overlap area of ​​the first and second oil inlets. Simultaneously, the external pressure sensor 10-1 above the upper sealing protrusion 6-3 and the internal pressure sensor 10-2 inside the central tube collect the formation pressure and the internal pressure of the central tube 3 in real time. The rotary encoder on the transmission sleeve 6-1 accurately feeds back the opening of the oil inlet channel. All this data is uploaded to the control unit. The control unit analyzes this data in real time and dynamically adjusts the output of the drive unit, forming a complete closed-loop control process. Therefore, the production distribution device disclosed in this invention can accurately maintain the output of each layer at the optimal state based on the actual formation conditions and the real-time changes in the internal state of the central tube 3.

[0031] The above description is merely a preferred embodiment of the present utility model and does not constitute any limitation on the present utility model. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present utility model shall still fall within the protection scope of the present utility model.

Claims

1. A downhole production distribution device for a small-diameter oil well, comprising, from bottom to top, an upper connector (1), an outer protective pipe (2), a screen pipe (4), and a lower connector (5), and further comprising a central pipe (3) disposed inside the outer protective pipe (2), the screen pipe (4), and the lower connector (5), characterized in that, Also includes: A stepped sleeve (6) is disposed between the outer protective tube (2), the screen tube (4), and the central tube (3). The stepped sleeve (6) includes a transmission sleeve (6-1) on the upper side and a functional sleeve (6-2) on the lower side. The outer diameter of the transmission sleeve (6-1) is smaller than the outer diameter of the functional sleeve (6-2). Both ends of the functional sleeve (6-2) are provided with radially protruding sealing protrusions (6-3). The two sealing protrusions (6-3) are rotatably connected to the inner wall of the outer protective tube (2) and the inner wall of the lower connector (5), respectively. A first oil inlet (3-1) is provided on one side of the functional sleeve (6-2). The first oil inlet (3-1) is located between the two sealing protrusions (6-3). A second oil inlet (3-2) is provided on the side wall of the central tube (3). In the initial position, the first oil inlet (3-1) and the second oil inlet (3-2) are staggered. A drive unit (7) is disposed on the upper side of the functional sleeve (6-2), and the drive unit is used to drive the stepped sleeve (6) to rotate.

2. The downhole production distribution device for small-diameter oil wells according to claim 1, characterized in that, The drive unit includes a motor bracket (7-1) disposed on the inner wall of the outer protective tube (2), a motor (7-2) disposed on the motor bracket (7-1), the output shaft of the motor (7-2) is vertically downward and connected to a transmission rod (7-4) through a coupling (7-3), a drive gear (7-5) disposed on the transmission rod (7-4), and a driven gear (6-4) meshing with the drive gear (7-5) disposed on the transmission sleeve (6-1), and the motor (7-2) is connected to the control unit.

3. The downhole production distribution device for small-diameter oil wells according to claim 2, characterized in that, The two sealing protrusions (6-3) at the upper and lower ends are rotatably connected to the outer protective tube (2) and the lower connector (5) via bearings (8).

4. The downhole production distribution device for small-diameter oil wells according to claim 1, characterized in that, The outer protective tube (2) has a pressure guiding hole (9) on its wall. The pressure guiding hole (9) is located above a sealing protrusion (6-3) on the upper side. An external pressure sensor (10-1) for detecting the bottom pressure is installed in the pressure guiding hole (9). An internal pressure sensor (10-2) for detecting the internal pressure is installed on the inner wall of the central tube (3). Both the external pressure sensor (10-1) and the internal pressure sensor (10-2) are connected to the control unit.

5. The downhole production distribution device for small-diameter oil wells according to claim 4, characterized in that, A moisture content sensor (11) is also provided on the inner wall of the central tube (3), and the moisture content sensor (11) is connected to the control unit.

6. The downhole production distribution device for small-diameter oil wells according to claim 4, characterized in that, A rotary encoder is provided on the transmission sleeve (6-1), and the rotary encoder is connected to the control unit.

7. The downhole production distribution device for small-diameter oil wells according to claim 1, characterized in that, The functional sleeve (6-2) and the side wall of the central tube (3) are respectively provided with a first balance hole and a second balance hole. In the initial position, the first balance hole and the second balance hole are aligned and connected to form a balance channel.

8. The downhole production distribution device for small-diameter oil wells according to claim 1, characterized in that, A first sealing ring (14) is provided in the annular gap between the functional sleeve (6-2) and the central tube (3), and a second sealing ring (15) is provided in the annular gap between the transmission sleeve (6-1) and the central tube (3). The first sealing ring (14) and the second sealing ring (15) are both located at the two ends of the first oil inlet (3-1) and the second oil inlet (3-2).

9. A downhole production distribution device for small-diameter oil wells according to claim 1, characterized in that, The inner walls of the outer protective tube (2) and the lower connector (5) are provided with connecting grooves corresponding to the sealing protrusions (6-3). The two sealing protrusions (6-3) are rotatably connected to the outer protective tube (2) and the lower connector (5) through the connecting grooves.

10. A downhole production distribution device for small-diameter oil wells according to claim 9, characterized in that, Each of the connecting grooves is provided with a third sealing ring (12).

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