An automatic monitoring device for oil well liquid level in oil field

Abstract

The present invention discloses an automatic monitoring device for the liquid level of an oil well in an oil field, comprising a measuring mechanism, which is arranged in an annulus and comprises an annular support plate, an acoustic wave transmitter and an acoustic wave receiver. The acoustic wave transmitter and the acoustic wave receiver are arranged below the annular support plate and are electrically connected to a control box outside the annulus through a data line, the control box is connected to a control center, the annular support plate is installed below a bearing and is connected to an inner ring of the bearing; a transmission mechanism is arranged on the outside of the annulus, the transmission mechanism is magnetically connected to the annular support plate, and a driving mechanism is connected to the side of the transmission mechanism; the present invention arranges a measuring mechanism, arranges an acoustic wave transmitter and an acoustic wave receiver below the annular support plate and is installed in the annulus, can measure the depth of the liquid level in the annulus by using the acoustic wave transmitter and the acoustic wave receiver using the echo principle, and sends the acquired information to the control center, providing support for the staff to take corresponding measures.

Description

Technical Field

[0001] The invention relates to the technical field of oil well liquid level monitoring, in particular to an automatic monitoring device for oil well liquid level in an oil field. Background Art

[0002] In the early stages of oil field exploitation, a cylindrical hole channel, namely an oil well, will be dug or drilled at the corresponding location. It is an important channel connecting the ground and underground reservoirs. It is generally composed of structures such as well walls and casings, extending from the wellhead to the deep of the target formation.

[0003] After the oil well is formed, it is necessary to insert multiple sections of oil pipes connected end to end into the oil well. The oil pipe is used to pump oil through the cooperation of the Christmas tree and the beam pumping unit, that is, the up and down reciprocating motion of the donkey head drives the sucker rod to reciprocate up and down in the oil pipe. The sucker rod is closely matched with the oil pipe, and the lower end of the sucker rod is connected to the piston of the oil pump (generally located downhole near the oil layer). When the nodding machine drives the sucker rod to move upward, the piston also moves upward, the space in the oil pipe increases, and the pressure decreases. Under the action of the oil layer pressure, the crude oil will enter the oil pump through the annular space (annulus) between the oil pipe and the casing to achieve the suction of crude oil. When the sucker rod drives the piston to move downward, the piston squeezes the crude oil in the oil pump, so that it is lifted to the ground through the oil pipe and enters the ground gathering and transportation system. Therefore, the oil pipe plays an important role in providing an upward transportation channel for crude oil and cooperating with the sucker rod to realize the pumping action.

[0004] From the above, it can be seen that in the process of oil production, the oil in the annulus flows into the oil pipe, and the oil can be continuously pumped out under the action of the beam pumping unit, which means that the liquid surface in the annulus has an important impact on oil production.

[0005] For example, the height of the liquid level in the annulus is directly related to the load borne by the suspension point of the beam pump. When the annulus liquid level is high, it means that the liquid column in the wellbore generates a large back pressure on the pump. The pump needs to overcome greater resistance in the process of lifting the sucker rod upward, and the suspension point load will increase. Conversely, if the annulus liquid level drops, the back pressure decreases, and the suspension point load decreases accordingly.

[0006] The annular liquid level reflects the fluid supply capacity of the oil well and is one of the key bases for determining the reasonable strokes (the number of up and down reciprocating movements of the sucker rod per minute) and stroke (the maximum stroke of the up and down movement of the sucker rod) of the pumping unit. If the annular liquid level continues to be at a low level, it indicates that the oil layer is not supplied with enough fluid. At this time, if the strokes and strokes are still maintained at a high level, the pumping unit may experience empty pumping, which not only wastes energy, but also easily causes problems such as the sucker rod being disengaged and the pump being worn out. When the annular liquid level is high and the fluid supply is sufficient, the strokes and strokes can be appropriately increased to increase crude oil production, but factors such as the carrying capacity of the equipment must also be considered.

[0007] The annular liquid level is a direct reflection of the oil layer's fluid supply capacity. By continuously monitoring the changing trend of the annular liquid level, the production dynamics of the oil layer can be understood. For example, if the annular liquid level gradually decreases and is difficult to recover, it may mean that the energy of the oil layer is constantly depleting, and it is necessary to take corresponding reservoir production-increasing measures in a timely manner, such as water injection to supplement the formation pressure, and fracturing transformation, in order to improve the oil layer's fluid supply capacity, ensure the continuous and stable exploitation of the oil well, and achieve better reservoir development results.

[0008] Therefore, accurately understanding the annular liquid level will help to reasonably adjust the working parameters of the pumping unit and achieve efficient oil production. At present, there are two ways to monitor the liquid level in oil wells: manual periodic measurement method and dynamometer indirect analysis method. The manual periodic measurement method requires staff to use sounding tools, such as steel wire and echo sounder, to regularly lower them into the wellbore to measure the liquid depth. It has high labor intensity, poor real-time performance, and limited measurement accuracy. The dynamometer indirect analysis method indirectly infers the approximate situation of the oil well liquid level by analyzing the dynamometer diagram of the load change of the donkey head suspension point of the pumping unit with the displacement. It has insufficient accuracy and high professional requirements. Summary of the invention

[0009] The purpose of the present invention is to provide an automatic monitoring device for the liquid level in an oil field oil well, aiming to provide a structure for monitoring the change of the annular liquid level for oil well exploitation, so as to take corresponding measures according to the demand.

[0010] The present invention is implemented as follows: an automatic monitoring device for the liquid level of an oil well in an oil field includes a measuring mechanism, which is arranged in an annulus and includes an annular support plate, an acoustic wave transmitter and an acoustic wave receiver. The acoustic wave transmitter and the acoustic wave receiver are arranged below the annular support plate and are electrically connected to a control box outside the annulus through a data line. The control box is connected to a control center. The annular support plate is installed below the bearing and is connected to the inner ring of the bearing; a transmission mechanism is arranged on the outside of the annulus, the transmission mechanism is magnetically connected to the annular support plate, and a driving mechanism is connected to the side of the transmission mechanism, and the driving mechanism controls the forward and reverse rotation of the transmission mechanism.

[0011] Preferably, a threaded column is fixedly arranged on the top of the sound wave transmitter and the sound wave receiver, two threaded holes are arranged on the annular support plate, and the two threaded columns are respectively threadedly inserted into the two threaded holes.

[0012] Preferably, the inner diameters of the bearing and the annular support plate are larger than the inner diameter of the annulus, a connecting rod is fixedly arranged below the inner ring of the bearing, a connecting hole is arranged on the annular support plate, the connecting rod passes through the connecting hole, and a nut is threadedly sleeved on the end.

[0013] Preferably, the outer diameter of the bearing is less than or equal to the outer diameter of the annulus, and a connecting plate is fixedly arranged above the outer ring of the bearing, the connecting plate is arranged in an L-shaped structure, and the top is suspended on the top of the annulus.

[0014] Preferably, the transmission mechanism includes two first arc plates and two second arc plates, the central angles of the two first arc plates and the two second arc plates are both set to 180°, and the two second arc plates are spliced ​​and connected to be arranged on the inner side of the two first arc plates and sleeved on the sleeve.

[0015] Preferably, a first arcuate groove is provided on the inner side surface of the first arcuate plate, a second arcuate groove is provided on the outer side surface of the second arcuate plate, and a plurality of rollers are provided in a space formed by the first arcuate groove and the second arcuate groove.

[0016] Preferably, a top arc plate is fixedly arranged above the first arc plate, a second magnet is embedded in the top arc plate, a first magnet is embedded in the side wall of the annular support plate, and the first magnet and the second magnet are magnetically connected.

[0017] Preferably, the driving mechanism includes a motor and a gear, the gear is fixedly arranged on the output shaft of the motor, a rack is arranged on the outer side of the first arc plate, the central angle of the rack is also set to 180°, and the two racks are alternately meshed with the gear.

[0018] Preferably, the driving mechanism further comprises a bracket, which is mounted on the end of the motor and is provided with a clamp at the end, which is sleeved on the sleeve and located below the transmission mechanism.

[0019] Preferably, the data line connected to the acoustic wave transmitter and the acoustic wave receiver passes through the gap formed by the annular support plate and the annulus, and the connecting plate and the data line extend to the top of the annulus and pass through the connecting surface of the Christmas tree and the casing.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention is provided with a measuring mechanism, and the sound wave transmitter and the sound wave receiver are arranged below the annular support plate and installed in the annulus. The depth of the liquid surface in the annulus can be measured by the sound wave transmitter and the sound wave receiver using the echo principle, and the acquired information is sent to the control center to provide support for the staff to take corresponding measures.

[0022] 2. The present invention is provided with a bearing, and the outer ring of the bearing is stably installed relative to the sleeve through a connecting plate, and the inner ring is stably connected to the annular support plate through a connecting rod, so that the movable installation of the sound wave transmitter and the sound wave receiver can be realized. Therefore, the position of the sound wave transmitter and the sound wave receiver can be adjusted under the action of external force, providing support for obtaining multiple sets of measurement data to obtain more accurate liquid level depth.

[0023] 3. The present invention is provided with a transmission mechanism and a driving mechanism, and the transmission mechanism can be controlled to rotate under the action of the driving mechanism. Therefore, the transmission mechanism is magnetically connected to the annular support plate. Therefore, when the transmission mechanism rotates, the annular support plate can be controlled to drive the sound wave transmitter and the sound wave receiver to adjust their positions, thereby providing convenience for obtaining multiple sets of data. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0025] Figure 2 It is a structural schematic diagram of the sleeve, driving mechanism, measuring mechanism and transmission mechanism of the present invention;

[0026] Figure 3 It is a structural schematic diagram of the driving mechanism, measuring mechanism and transmission mechanism of the present invention;

[0027] Figure 4 It is a structural schematic diagram of the driving mechanism of the present invention;

[0028] Figure 5 It is a structural schematic diagram of the transmission mechanism of the present invention;

[0029] Figure 6 is a schematic structural diagram of a second curved plate of the present invention;

[0030] Figure 7 It is a structural schematic diagram of the measuring mechanism of the present invention;

[0031] Figure 8 It is a structural schematic diagram of the bearing of the present invention;

[0032] Fig. 9 It is a structural schematic diagram of the annular support plate of the present invention.

[0033] In the figure: 1, Christmas tree; 11, control box; 12, casing; 13, control center; 14, annulus; 15, oil pipe; 2, driving mechanism; 21, motor; 22, bracket; 23, clamp; 24, gear; 3, measuring mechanism; 31, sound wave transmitter; 311, threaded column; 32, sound wave receiver; 33, annular support plate; 331, threaded hole; 332, connecting hole; 333, first magnet; 34, bearing; 341, connecting rod; 342, connecting plate; 4, transmission mechanism; 41, rack; 42, first arc groove; 43, first arc plate; 44, roller; 45, second arc plate; 46, second arc groove; 47, top arc plate; 48, second magnet. DETAILED DESCRIPTION

[0034] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] The following is a further description with reference to the accompanying drawings and specific embodiments:

[0036] Example 1

[0037] like Figure 1 As shown, in order to continuously monitor the changes in the liquid level in the annulus (the cavity formed by the casing 12 and the oil pipe 15) and provide support for taking corresponding measures for oil production, this embodiment provides a liquid level monitoring device. The device includes a measuring mechanism 3, a control box 11, etc. The measuring mechanism 3 is stably set in the annulus, and uses the echo principle to measure the liquid level depth, and transmits the measurement information to the control box 11, and then the control box 11 sends the data to the control center 13, which can facilitate the staff to access the corresponding data and make judgments.

[0038] like Figure 7 As shown, specifically, the measuring mechanism 3 includes an annular support plate 33, an acoustic wave transmitter 31 and an acoustic wave receiver 32. Both the acoustic wave transmitter 31 and the acoustic wave receiver 32 are detachably arranged below the annular support plate 33. The acoustic wave transmitter 31 and the acoustic wave receiver 32 can be set as piezoelectric acoustic wave transmitters and piezoelectric acoustic wave receivers. The inner diameter of the annular support plate 33 is larger than the inner diameter of the annulus, and a connecting plate 342 can be arranged on the top. The connecting plate 342 is arranged in an L-shaped structure, and the top is suspended on the top of the annulus, that is, the top of the connecting plate 342 is arranged on the contact surface of the casing 12 and the Christmas tree, so as to achieve stable installation of the annular support plate 33. A sealing ring is arranged at the contact surface to achieve a sealed connection between the casing 12 and the Christmas tree, thereby avoiding damage to the connecting plate 342 due to extrusion. Since the inner diameter of the annular support plate 33 is larger than the inner diameter of the annulus, a gap is left between the annular support plate 33 and the oil pipe 15. Therefore, the data line connecting the control box 11 with the acoustic wave transmitter 31 and the acoustic wave receiver 32 is arranged through the gap. In addition, the data line passes through the contact surface between the casing 12 and the Christmas tree and is connected to the control box 11.

[0039] like Fig. 9As shown, in order to stably install the sound wave transmitter 31 and the sound wave receiver 32 under the annular support plate 33, a threaded column 311 is fixedly arranged on the top of the sound wave transmitter 31 and the sound wave receiver 32, and two threaded holes 331 are arranged on the annular support plate 33. The two threaded columns 311 are respectively threadedly inserted into the two threaded holes 331. Therefore, under the cooperation of the threaded holes 331 and the threaded columns 311, the sound wave transmitter 31 and the sound wave receiver 32 can be stably installed under the annular support plate 33, and it is convenient to disassemble according to needs. The above-mentioned two threaded holes 331 can be arranged adjacent to each other, or they can be distributed at both ends of the same diameter of the annular support plate 33. In short, the installation positions of the sound wave transmitter 31 and the sound wave receiver 32 are determined according to actual needs, which is convenient for completing the liquid level measurement.

[0040] In order to obtain data from the acoustic wave transmitter 31 and the acoustic wave receiver 32, a microcontroller (MCU), circuit breakers, contactors, relays, fuses, power modules, terminal blocks, etc. are provided in the control box 11. The acoustic wave transmitter 31 and the acoustic wave receiver 32 are connected to the control box 11, such as a dedicated drive circuit and a signal conditioning circuit, and their output signals can be connected to specific input pins of the microcontroller through these circuits; the power pin is connected to the output end of the power module in the control box, etc.

[0041] Under the action of the microcontroller, the data provided by the sound wave transmitter 31 and the sound wave receiver 32 can be amplified, filtered, analog-to-digital converted, feature extracted and analyzed, and then the data can be sent to the control center 13 via wired or wireless connection.

[0042] Example 2

[0043] like Figure 7 , Figure 8 As shown, on the basis of Example 1, in order to be able to control the adjustment position of the sound wave transmitter 31 and the sound wave receiver 32, even if the sound waves are reflected at different positions of the liquid surface to obtain multiple sets of measurement data, the annular support plate 33 can be movably set inside the annulus.

[0044] Specifically, a bearing 34 is disposed above the annular support plate 33, and the inner diameter of the bearing 34 is larger than the inner diameter of the annulus. A connecting plate 342 is disposed above the bearing 34, that is, the connecting plate 342 is mounted on the outer ring of the bearing 34, and under the action of the connecting plate 342, the bearing 34 is stably mounted in the annulus.

[0045] like Figure 8 , Fig. 9As shown in the figure, in order to stably connect the annular support plate 33 to the bearing 34, a plurality of connecting rods 341 are fixedly arranged below the inner ring of the bearing 34. Connecting holes 332 are provided on the annular support plate 33. The connecting rods 341 penetrate through the connecting holes 332, and nuts are sleeved on the ends of the connecting rods 341 by threads. Therefore, under the action of the nuts and the connecting rods 341, the annular support plate 33 is stably installed below the bearing 34 and provides support for the annular support plate 33 to rotate relative to the annulus under the action of an external force.

[0046] In order to be able to meet the forward and reverse rotation of the acoustic wave transmitter 31 and the acoustic wave receiver 32, sufficient lengths of the data lines of the acoustic wave transmitter 31 and the acoustic wave receiver 32 are reserved in the annulus to provide support for their rotation.

[0047] As Figure 2 、 Figure 3 、 Figure 4 As shown in the figure, in order to be able to control the annular support plate 33 to drive the acoustic wave transmitter 31 and the acoustic wave receiver 32 to rotate, a transmission mechanism 4 and a driving mechanism 2 are arranged on the outer side of the casing 12. The transmission mechanism 4 is directly sleeved on the casing 12 and is magnetically connected to the annular support plate 33. Therefore, when the transmission mechanism 4 rotates, the annular support plate 33 will also rotate. The driving mechanism 2 is installed on the casing 12 and is connected to the transmission mechanism 4. Therefore, under the action of the driving mechanism 2, the rotation of the transmission mechanism 4 can be controlled, and then the annular support plate 33 is forced to rotate.

[0048] As Figure 5 As shown in the figure, in order to stably install the transmission mechanism 4 on the casing 12, the transmission mechanism 4 includes two first arc-shaped plates 43 and two second arc-shaped plates 45. The central angles of the two first arc-shaped plates 43 and the two second arc-shaped plates 45 are both set to 180°. The two second arc-shaped plates 45 are spliced and connected and arranged inside the two first arc-shaped plates 43 and sleeved on the casing.

[0049] As Figure 5 、 Figure 6 As shown in the figure, in order to stably install the first arc-shaped plate 43 on the outer side of the second arc-shaped plate 45, a first arc-shaped groove 42 is provided on the inner side surface of the first arc-shaped plate 43, and a second arc-shaped groove 46 is provided on the outer side surface of the second arc-shaped plate 45. The cross-sections of the first arc-shaped groove 42 and the second arc-shaped groove 46 are both set to a U-shaped structure, and a plurality of rollers 44 are arranged in the space formed by the first arc-shaped groove 42 and the second arc-shaped groove 46. Therefore, under the action of the rollers 44, the stable connection between the first arc-shaped plate 43 and the second arc-shaped plate 45 is realized, and support is provided for the first arc-shaped plate 43 to rotate relative to the second arc-shaped plate 45.

[0050] As Figure 5 、 Fig. 9As shown, in order to realize the magnetic connection between the transmission mechanism 4 and the annular support plate 33, a top arc plate 47 is fixedly arranged above the first arc plate 43, a second magnet 48 is embedded on the top arc plate 47, and a first magnet 333 is embedded on the side wall of the annular support plate 33. The first magnet 333 and the second magnet 48 are magnetically connected. Therefore, with the cooperation of the first magnet 333 and the second magnet 48, the magnetic connection between the first arc plate 43 and the annular support plate 33 can be realized, providing support for the first arc plate 43 to drive the annular support plate 33 to rotate. Under this setting, the sleeve 12 should be made of weakly magnetic or non-magnetic materials, such as austenitic stainless steel, which can meet the synchronous rotation of the inner and outer magnets.

[0051] like Figure 4 As shown, in order to be able to control the forward and reverse rotation of the first arc plate 43, the driving mechanism 2 includes a motor 21 (which can be set as a servo motor, a stepping motor, etc.) and a gear 24. The gear 24 is fixedly arranged on the output shaft of the motor 21. A rack 41 is arranged on the outer side of the first arc plate 43. The central angle of the rack 41 is also set to 180°, and the two racks 41 are alternately meshed and connected with the gear 24. With the cooperation of the rack 41 and the gear 24, the power of the motor 21 can be transmitted to the first arc plate 43, thereby controlling the forward and reverse rotation of the two first arc plates 43, forcing the annular support plate 33 to drive the sound wave transmitter 31 and the sound wave receiver 32 to adjust their positions, and providing support for obtaining multiple sets of measurement data.

[0052] In order to ensure stable installation of the motor 21 , the drive mechanism 2 further includes a bracket 22 . The bracket 22 is installed at the end of the motor 21 and a clamp 23 is provided at the end. The clamp 23 is sleeved on the sleeve 12 and is located below the transmission mechanism 4 .

[0053] The motor 21 is also connected to the control box 11. The power line is generally directly connected to the input terminal of the circuit breaker, and the circuit breaker controls the on-off control and short-circuit protection of the motor power supply. The microcontroller is connected to the control coil of the relay or contactor through the output pin. According to the preset program and algorithm, the level of these pins is controlled to control the contactor or contactor to close and open, thereby realizing the start, stop, forward and reverse rotation of the motor.

[0054] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An automatic monitoring device for the liquid level of an oil well in an oil field, characterized in that: The measuring mechanism (3) comprises a measuring mechanism (3), which is arranged in an annular space (14) and comprises an annular support plate (33), a sound wave transmitter (31) and a sound wave receiver (32). The sound wave transmitter (31) and the sound wave receiver (32) are arranged below the annular support plate (33) and are electrically connected to a control box (11) outside the annular space (14) through a data line, and the control box (11) is connected to a control center (13); the annular support plate (33) is installed below a bearing (34) and is connected to the inner ring of the bearing (34); a transmission mechanism (4) is arranged outside the annular space (14), the transmission mechanism (4) is magnetically connected to the annular support plate (33), and a driving mechanism (2) is connected to the side of the transmission mechanism (4), and the driving mechanism (2) controls the forward and reverse rotation of the transmission mechanism (4).

2. The automatic monitoring device for oil well liquid level in an oil field according to claim 1, characterized in that: A threaded column (311) is fixedly arranged on the top of the sound wave transmitter (31) and the sound wave receiver (32), two threaded holes (331) are arranged on the annular support plate (33), and the two threaded columns (311) are respectively threadedly inserted into the two threaded holes (331).

3. The automatic monitoring device for oil well liquid level in an oil field according to claim 2, characterized in that: The inner diameters of the bearing (34) and the annular support plate (33) are larger than the inner diameter of the annulus (14). A connecting rod (341) is fixedly arranged below the inner ring of the bearing (34). A connecting hole (332) is arranged on the annular support plate (33). The connecting rod (341) passes through the connecting hole (332) and a nut is threadedly sleeved on the end thereof.

4. The automatic monitoring device for the liquid level in an oil field well according to claim 3, characterized in that: The outer diameter of the bearing (34) is smaller than or equal to the outer diameter of the annulus (14), and a connecting plate (342) is fixedly arranged above the outer ring of the bearing (34). The connecting plate (342) is arranged in an L-shaped structure, and the top is suspended on the top of the annulus (14).

5. The automatic monitoring device for oil well liquid level in an oil field according to claim 1, characterized in that: The transmission mechanism (4) comprises two first curved plates (43) and two second curved plates (45), the central angles of the two first curved plates (43) and the two second curved plates (45) are both set to 180°, and the two second curved plates (45) are spliced ​​and connected to be arranged on the inner sides of the two first curved plates (43) and sleeved on the sleeve (12).

6. The automatic monitoring device for the liquid level in an oil field well according to claim 5, characterized in that: A first arc-shaped groove (42) is arranged on the inner side surface of the first arc-shaped plate (43), a second arc-shaped groove (46) is arranged on the outer side surface of the second arc-shaped plate (45), and a plurality of rollers (44) are arranged in a space formed by the first arc-shaped groove (42) and the second arc-shaped groove (46).

7. The automatic monitoring device for the liquid level in an oil field well according to claim 5, characterized in that: A top arc plate (47) is fixedly arranged above the first arc plate (43), a second magnet (48) is embedded in the top arc plate (47), a first magnet (333) is embedded in the side wall of the annular support plate (33), and the first magnet (333) and the second magnet (48) are magnetically connected.

8. The automatic monitoring device for the liquid level in an oil field well according to claim 5, characterized in that: The driving mechanism (2) comprises a motor (21) and a gear (24); the gear (24) is fixedly arranged on the output shaft of the motor (21); a rack (41) is arranged on the outer side of the first arc-shaped plate (43); the central angle of the rack (41) is also set to 180°, and two racks (41) are alternately meshed and connected with the gear (24).

9. The automatic monitoring device for the liquid level in an oil field well according to claim 8, characterized in that: The driving mechanism (2) further comprises a bracket (22), the bracket (22) being mounted on the end of the motor (21) and having a clamp (23) disposed on the end, the clamp (23) being sleeved on the sleeve (12) and located below the transmission mechanism (4).

10. The automatic monitoring device for the liquid level in an oil well of an oil field according to claim 4, characterized in that: A data line connected to the acoustic wave transmitter (31) and the acoustic wave receiver (32) is arranged to pass through a gap formed by the annular support plate (33) and the annulus (14); the connecting plate (342) and the data line both extend to the top of the annulus (14) and pass through a connection surface between the Christmas tree (1) and the casing (12).

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