A plunger arrival sensor and a method for using the same

Abstract

The present invention provides a plunger arrival sensor and a method for using the same, including a mounting seat. The mounting seat has a blind tube structure, and the lower end of the plunger has a hollow structure. The blind tube end of the mounting seat extends into the lower end of the plunger and is sealed between the side wall of the plunger through a sealing ring. A Hall sensor is fixed between the blind tube end of the mounting seat and the bottom of the hollow structure at the lower end of the plunger. The other end of the mounting seat is plugged with a compression plug. An opening is made along the axial direction of the plunger on the compression plug. One end of the collision rod extends into the mounting seat through the opening on the compression plug, and a magnet is fixed on one end of the collision rod, and a spring is pressed between the one end of the collision rod and the blind tube end of the mounting seat. To solve the problem that the operation effect of the plunger drainage process cannot be accurately evaluated. It belongs to the technical field of downhole testing instruments for gas wells.

Description

Technical Field

[0001] The present invention relates to a plunger arrival sensor and a method for using the same, belonging to the technical field of downhole testing instruments for gas wells. Background Art

[0002] During the production process of natural gas wells, liquid accumulates in the wellbore. It is necessary to drain the liquid in time to ensure the continuous production of natural gas. Currently, the plunger gas lift drainage gas production process is the main technology for drainage gas production in low-yield gas wells in China. The principle of the plunger gas lift drainage gas production technology can be vividly compared to a pneumatic pump with a very long stroke. Taking the plunger as the piston and the entire tubing as the pump barrel, when the well is opened for production, the gas energy at the bottom of the well pushes the plunger and the liquid above the plunger from the bottom of the well to the wellhead. After the well is shut in, the plunger falls back to the bottom of the well under its own gravity. In each drainage stroke of the plunger, the most efficient drainage situation is that the plunger can start from the bottom limiter position (the lowest point of the stroke) and reach the wellhead limiter position (the highest point of the stroke) in each drainage stroke. Therefore, understanding whether the plunger in each gas well can reach the bottom and the wellhead during the drainage process can effectively and intuitively evaluate the operation effect of the plunger drainage gas production process in this gas well. Currently, whether the plunger reaches the wellhead can be easily obtained through the detection instrument installed at the wellhead, while there is no simple and reliable way to obtain the data on whether the plunger reaches the bottom.

[0003] To meet this need, this patent proposes a design solution that can be used to judge and record whether the plunger reaches the bottom limiter in each drainage stroke, facilitating the subsequent evaluation by technical personnel of the operation effect of the plunger drainage gas production process. Summary of the Invention

[0004] The present invention provides a plunger arrival sensor and a method for using the same to solve the problem that the operation effect of the plunger drainage process cannot be accurately evaluated.

[0005] To achieve the above object, a plunger arrival sensor is proposed, which includes a mounting seat. The mounting seat is a blind tube structure, and the lower end of the plunger is a hollow structure. The blind tube end of the mounting seat extends into the lower end of the plunger and is sealed with the side wall of the plunger through a sealing ring. A Hall sensor is fixed between the blind tube end of the mounting seat and the bottom of the hollow structure at the lower end of the plunger. A compression plug is plugged into the other end of the mounting seat. An opening is drilled along the axial direction of the plunger on the compression plug. One end of a collision rod extends into the mounting seat through the opening on the compression plug, and a magnet is fixed at one end of the collision rod, and a spring is pressed between the blind tube end of the mounting seat and the one end of the collision rod.

[0006] In the aforementioned plunger arrival sensor, a battery and a circuit board are also embedded at the bottom of the hollow structure at the lower end of the plunger. The Hall sensor is connected to the circuit board and transmits the signal received by the Hall sensor to the circuit board. The battery is connected to the circuit board to supply power to the circuit board.

[0007] The aforementioned plunger reaches the sensor, and the diameter of the collision rod is 10 - 20 mm.

[0008] In the aforementioned plunger reaching the sensor, the magnetic steel is a high-temperature resistant rare earth magnetic steel;

[0009] In the aforementioned plunger reaching the sensor, the mounting seat is made of non-magnetic steel.

[0010] The usage method of the above-mentioned plunger reaching the sensor is as follows:

[0011] Install and fix the mounting seat at the lower end of the plunger according to the above structure. The movable collision rod protrudes from the bottom of the plunger under the action of the spring. When the plunger reaches the bottom well stopper, the front end of the collision rod will first touch the step surface of the stopper. Under the action of the gravity of the plunger, the collision rod moves into the plunger against the elastic force of the spring. A magnetic steel is installed inside the collision rod. During the movement of the collision rod, the magnetic steel gets closer and closer to the circuit board, and the magnetic field signal generated by the magnetic steel will become stronger and stronger. Since the mounting seat is made of non-magnetic steel, the Hall sensor installed at the center of the circuit board will detect the change of the magnetic field signal and record the change of the magnetic field intensity through the memory on the circuit board. After the plug is taken out regularly, the data is recovered, and whether the magnetic field intensity value reaches the set limit is obtained through the recovered data to judge whether the plunger reaches the bottom of the well.

[0012] Compared with the prior art, the use of the present invention enables oilfield technicians to clearly understand whether the plunger can reach the bottom of the well during each drainage stroke only by taking out the plunger for data playback after the plunger has run for a period of time, and combined with the data of the plunger reaching the wellhead measured on the ground, the operation efficiency of the plunger drainage gas production process during this period can be accurately evaluated. At the same time, the sensor and its usage method also have the following advantages: The moving parts in the sensor are completely sealed and isolated from the circuit part, ensuring the high reliability of the device; The moving parts will not touch other positions except the bottom well stopper, and are not affected by external pressure, with strong anti-vibration interference ability and accurate and reliable test results; The sensor has a small and compact structure and is easy to install. In addition to being installed separately inside the plunger body for detecting the reaching situation, it can also be conveniently installed at the tail of other plunger test instruments as an additional functional component to expand the test function range of such instruments; The magnetic steel uses high-temperature resistant rare earth magnetic steel to ensure the stability of the magnetic signal in the downhole high-temperature environment; The power consumption of the sensor is very low, which is beneficial to the application of the sensor on downhole storage-type instruments.

[0013] By adopting the above technology, the invention effectively solves the technical problem of judging whether the plunger reaches the bottom of the well, and can effectively help oilfield technicians accurately evaluate the operation effect of the plunger drainage gas production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1It is a schematic structural diagram of the present invention that has not reached the bottom of the well;

[0015] Figure 2 It is a schematic structural diagram of the present invention that has reached the bottom of the well. Detailed implementation manners

[0016] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] Embodiment

[0018] Refer to Figure 1 and Figure 2 In this embodiment, a plunger arrival sensor is provided, including a plunger 1. The lower end of the plunger 1 is a hollow structure. The mounting seat 6 is a blind tube structure made of non-magnetic steel. The blind tube end of the mounting seat 6 extends into the lower end of the plunger 1 and is sealed between the side wall of the plunger 1 through a sealing ring 5. A Hall sensor 4 is fixed between the blind tube end of the mounting seat 6 and the bottom of the hollow structure at the lower end of the plunger 1. The other end of the mounting seat 6 is plugged with a compression plug 9. The compression plug 9 is axially drilled along the plunger 1. The diameter of the collision rod 10 is 10-20 mm. One end of the collision rod 10 extends into the mounting seat 6 through the hole in the compression plug 9. A magnet 8 is fixed on one end of the collision rod 10, and a spring 7 is pressed between the magnet 8 and the blind tube end of the mounting seat 6. The magnet 8 is a high-temperature resistant rare earth magnet. A battery 2 and a circuit board 3 are also embedded in the bottom of the hollow structure at the lower end of the plunger 1. The Hall sensor 4 is connected to the circuit board 3 and transmits the signal received by the Hall sensor 4 to the circuit board 3. The battery 2 is connected to the circuit board 3 to supply power to the circuit board 3.

[0019] Its usage method is as follows:

[0020] Install and fix the mounting seat 6 at the lower end of the plunger 1 according to the above structure. The movable collision rod 10 protrudes from the bottom of the plunger 1 under the action of the spring 7. When the plunger 1 reaches the bottom well limiter, the front end of the collision rod 10 will first touch the step surface of the limiter. The collision rod 10 moves into the plunger 1 under the action of the gravity of the plunger 1 against the elastic force of the spring 7. A magnet 8 is installed inside the collision rod 10. During the movement of the collision rod 10, the magnet 8 gets closer and closer to the circuit board 3, and the magnetic field signal generated by the magnet 8 becomes stronger and stronger. Since the mounting seat 6 is made of non-magnetic steel, the Hall sensor 4 installed at the center of the circuit board 3 will detect the change of the magnetic field signal, record the change of the magnetic field intensity through the memory on the circuit board 3 and upload it to the upper computer through the signal transmission module. The upper computer judges whether the plunger 1 reaches the bottom of the well by judging whether the magnetic field intensity value reaches the set limit value.

[0021] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A plunger arrival sensor, characterized in that: It includes a mounting base (6). The mounting base (6) is a blind tube structure. The lower end of the plunger (1) is a hollow structure. The blind tube end of the mounting base (6) extends into the lower end of the plunger (1) and is sealed with the side wall of the plunger (1) through a sealing ring (5). A Hall sensor (4) is fixed between the blind tube end of the mounting base (6) and the bottom of the hollow structure at the lower end of the plunger (1). A compression plug (9) is plugged at the other end of the mounting base (6). The compression plug (9) is axially drilled along the plunger (1). One end of the collision rod (10) extends into the mounting base (6) through the hole in the compression plug (9). A magnet (8) is fixed at one end of the collision rod (10), and a spring (7) is pressed between the collision rod (10) and the blind tube end of the mounting base (6).

2. The plunger arrival sensor according to claim 1, wherein: A battery (2) and a circuit board (3) are also embedded at the bottom of the hollow structure at the lower end of the plunger (1). The Hall sensor (4) is connected to the circuit board (3) and transmits the signal received by the Hall sensor (4) to the circuit board (3). The battery (2) is connected to the circuit board (3) to supply power to the circuit board (3).

3. The plunger arrival sensor according to claim 1, wherein: The diameter of the collision rod (10) is 10 - 20 mm.

4. The plunger arrival sensor according to claim 1, wherein: The magnet (8) is a high-temperature resistant rare earth magnet.

5. The plunger arrival sensor according to claim 1, wherein: The mounting base (6) is made of non-magnetic steel.

6. The usage method of the plunger reaching the sensor according to any one of claims 1-5, characterized in that, The specific method is as follows: Install and fix the mounting base (6) at the lower end of the plunger (1) according to the above structure. The movable collision rod (10) protrudes from the bottom of the plunger (1) under the action of the spring (7). When the plunger (1) reaches the bottom well limiter, the front end of the collision rod (10) will first touch the step surface of the limiter. The collision rod (10) moves into the plunger (1) under the action of the gravity of the plunger (1) against the elastic force of the spring (7). A magnet (8) is installed inside the collision rod (10). During the movement of the collision rod (10), the magnet (8) gets closer and closer to the circuit board (3), and the magnetic field signal generated by the magnet (8) will become stronger and stronger. Since the mounting base (6) is made of non-magnetic steel, the Hall sensor (4) installed at the center of the circuit board (3) will detect the change of the magnetic field signal, record the change of the magnetic field intensity through the memory on the circuit board (3), and upload it to the upper computer through the signal transmission module. The upper computer judges whether the plunger (1) reaches the bottom of the well by judging whether the magnetic field intensity value reaches the set limit value.

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