Gas-liquid mixed pumping rod type pump and oil pumping string

Abstract

The gas-liquid mixed pumping rod type pump comprises a pump cylinder, a plunger body and a pull rod, the plunger body is arranged in the pump cylinder in a sliding mode, a fixed valve set is arranged at the position, below the plunger body, in the pump cylinder, the lower end of the pull rod is connected with the upper end of the plunger body, and a liquid drainage valve set is arranged at the lower end in the plunger body. The lower end of the plunger body is in sliding connection with the movable supporting rod mechanism; and the moving support rod mechanism can open a first valve ball of the drain valve group when the plunger body moves downwards. Under the action of friction force and pressure difference, the floating supporting rod mechanism can open the valve ball at the bottom of the plunger body, and the problem that high-gas-content well gas affects pump efficiency and even air locking is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to oil extraction equipment technical field, concretely is gas liquid mixed extraction rod formula pump and oil extraction pipe column. BACKGROUND

[0002] At present, low-permeability oil wells are more and more, these oil wells have the characteristics of low reservoir permeability and deep burial depth, in order to realize the lifting of these oil wells, the lifting pipe column of the pumping unit is mostly in the form of deep pump hanging, but it brings many problems, the operation cycle is long, the pipe column is down for a long time, and the damage to the pipe thread is serious, therefore, the rod pump lifting technology is formed, only the pipe column is down, the operation time is greatly reduced, and the damage to the pipe thread is reduced. But there is a problem of gas affecting pump efficiency.

[0003] Publication No. CN112576485B discloses an oil extraction pump for gas-containing heavy oil well, a gas-liquid displacement cavity is arranged on the pump cylinder assembly, when the plunger assembly moves upward to a certain stroke, the gas-liquid displacement cavity is communicated with the lower pump cavity to form a gas upward channel for displacing the gas in the lower pump cavity to the gas-liquid displacement cavity; when the plunger assembly moves downward to a certain stroke, the gas-liquid displacement cavity is communicated with the upper oil pipe cavity to form a gas discharge channel for displacing the gas in the gas-liquid displacement cavity to the upper oil pipe cavity and discharging. By adding the gas-liquid displacement cavity, the upward and discharge channels are provided for the gas in the pump, so that the gas-liquid mixing displacement and discharge functions are realized in the hydraulic feedback oil extraction pump, and the gas-liquid ratio in the pump for heavy oil containing gas is reduced.

[0004] The prior art uses the gas cavity to play a certain role, but for high gas content wells, it does not solve the problem of gas locking.

[0005] Publication No. CN117846550A discloses a gas lifting, machine pumping composite lifting and well killing operation integrated pipe column, a gas lifting valve is arranged on the pump, each gas lifting valve is arranged on the sidewall of the oil pipe on the upper part of the rod working cylinder, each stage gas lifting valve works with the rod oil extraction pump lifting system, and is commonly used for the high gas-liquid ratio production stage. In the process of continuous gas gathering and continuous casing pressure rising, when the casing pressure of the gas lifting valve is higher than the opening pressure, the gas lifting valve is opened, the oil casing annulus gas enters the oil pipe through the gas lifting valve, the liquid column density in the oil pipe above the gas lifting valve is reduced, and the liquid lifting to the ground is promoted.

[0006] The gas lifting valve in the prior art has an opening pressure and cannot help the pipe column to discharge gas in time.

[0007] The patent CN112594174A discloses an oil pumping pump for oil pumping unit to exploit oil and natural gas, which comprises a pump cylinder, a piston device, an annular bearing valve, a first traveling valve and a second traveling valve. The pump cylinder is a hollow columnar body with end covers arranged at both ends. The pump cylinder is provided with flow holes on the end covers. The piston device is arranged in the pump cylinder and can move along the axial direction of the pump cylinder. The piston device is a hollow structure, and both ends of the hollow structure are provided with flow holes. The first traveling valve is arranged in the hollow structure of the piston device. The inner side of one end of the pump cylinder is provided with the second traveling valve, and the second traveling valve is located on the same side of the pump cylinder as the first traveling valve. The piston device is provided with the annular bearing valve. When the piston device moves, the annular bearing valve can block the flow hole at the other end of the pump cylinder. The condition of the gas-liquid mixture entering and exiting the pump is improved.

[0008] The prior art only considers the influence of gas expansion on the upper valve body of the pump cylinder, and does not consider the influence of gas expansion on the lower valve body of the plunger body.

[0009] In summary, the technical solutions, the technical problems to be solved and the beneficial effects of the above disclosed technologies are different from those of the present utility model. The above disclosed technology documents do not have technical inspiration for more technical features, technical problems to be solved and beneficial effects of the present utility model. Utility model content

[0010] In view of the above defects of the prior art, the purpose of the present utility model is to provide a gas-liquid mixed pumping rod type pump and an oil pumping string.

[0011] In order to achieve the above purpose, the present utility model adopts the following technical solutions:

[0012] On the one hand, the present utility model provides a gas-liquid mixed pumping rod type pump, which comprises a pump cylinder, a plunger body and a pull rod. The plunger body is slidingly arranged in the pump cylinder. A fixed valve group is arranged below the plunger body inside the pump cylinder. The lower end of the pull rod is connected to the upper end of the plunger body. A liquid discharge valve group is arranged at the lower end inside the plunger body. A traveling support rod mechanism is slidingly connected to the lower end of the plunger body. The traveling support rod mechanism can open the first valve ball of the liquid discharge valve group when the plunger body moves downward.

[0013] Further, the liquid discharge valve group comprises a first valve ball and a first valve seat. The first valve seat is arranged at the lower end of the plunger body. The center of the first valve seat is a first valve hole. The first valve ball is seated in the first valve hole.

[0014] Specifically, the traveling support rod mechanism comprises a base body. The center of the base body is through.

[0015] Specifically, an elastic friction member is arranged on the outer wall of the base body. The elastic friction member forms an interference fit with the pump cylinder.

[0016] Specifically, the base upper end is provided with a lifting rod and a hanging ring;

[0017] Specifically, the hanging ring is provided with at least two and is uniformly distributed along the circumference of the base;

[0018] Specifically, the hanging ring is inserted into the first valve seat, and the hanging ring can be hung with the first valve seat;

[0019] Specificly, the base slides up and down through the hanging ring, and the lifting rod can be inserted into the first valve hole to lift the first valve ball.

[0020] Further, the hanging ring is an inverted L-shaped rod, and the first valve seat is provided with a hanging hole;

[0021] Specifically, the inverted L-shaped rod is inserted into the first valve seat, and the horizontal part of the inverted L-shaped rod can be in contact with the upper end surface of the first valve seat to achieve hanging;

[0022] Specifically, the hanging ring does not interfere with the first valve ball sitting on the first valve seat.

[0023] Further, the upper end surface of the lifting rod is an inclined cylindrical surface, and the lifting rod deviates from the axis of the first valve hole;

[0024] Specifically, the elastic friction part is a second leather cup, and the diffusion port of the second leather cup faces downward.

[0025] Further, the upper end of the pump barrel is provided with a joint, the outer wall of the pump barrel is provided with a sealing assembly, and the lower end of the pump barrel is connected with a locking mechanism; the pull rod passes through the joint.

[0026] Further, the pull rod is provided with an anti-falling ring above the joint, and the outer diameter of the anti-falling ring is greater than the inner diameter of the upper port of the joint.

[0027] Further, the joint comprises a fishing section and a liquid discharge section connected in sequence, the outer wall of the fishing section is provided with a fishing step, the liquid discharge section is conical downward, and the liquid discharge section is provided with a first liquid discharge flow channel.

[0028] Further, the inside of the pump barrel is provided with a slide valve above the plunger body, and the pull rod passes through the slide valve;

[0029] Specifically, the slide valve comprises a limiting ring and a sliding block, the center of the limiting ring is provided with a second liquid discharge flow channel, and the limiting ring is connected with the inner wall of the pump barrel;

[0030] Specifically, the outer diameter of the sliding block is greater than the diameter of the second liquid discharge flow channel, the sliding block can be seated on the limiting ring, and the second liquid discharge flow channel is blocked;

[0031] Specifically, when the sliding block is in contact with the liquid discharge section of the joint when ascending, the sliding block cannot block the first liquid discharge flow channel;

[0032] Specifically, the sliding block has an inner diameter larger than an outer diameter of the pull rod, and the sliding block forms a gap seal with the pull rod.

[0033] Further, the sealing assembly is a first leather cup, and the diffusion port of the first leather cup faces upward.

[0034] Specifically, the locking mechanism is a frustum-shaped tube, and a small-diameter end of the frustum-shaped tube faces downward.

[0035] In a second aspect, the utility model provides an oil extraction pipe column, which comprises, from top to bottom, an oil pipe, an outer cylinder, a screen pipe and a tail pipe, the outer wall of the oil pipe is provided with a packer, and the outer cylinder is provided with the gas-liquid mixed extraction rod type pump in the first aspect; the outer cylinder comprises, from top to bottom, a guide slope, a sealing section and a positioning end; the sealing section is in interference fit with the sealing assembly; the positioning end is in correspondence with the locking mechanism; and the positioning end is matched with the locking mechanism.

[0036] Compared with the prior art, the utility model has the following beneficial effects:

[0037] In the utility model, under the action of friction and pressure difference, the movable support rod mechanism can open the valve ball at the bottom of the plunger body, and the problem of gas affecting pump efficiency or even gas locking in a high gas content well is solved. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is the structural schematic view of the gas-liquid mixed extraction rod type pump of the utility model;

[0039] Figure 2 is the structural schematic view of the outer cylinder in the utility model;

[0040] Figure 3 is the structural schematic view of the movable support rod mechanism in the utility model;

[0041] Figure 4 is the structural schematic view of the oil extraction pipe column of the utility model.

[0042] In the drawing: 1, pull rod; 2, joint; 21, fishing step; 22, first liquid drainage channel; 3, sliding valve; 31, second liquid drainage channel; 4, sealing assembly; 5, pump cylinder; 6, plunger body; 61, third liquid drainage channel; 7, liquid drainage valve group; 8, movable support rod mechanism; 81, jacking rod; 82, suspension ring; 83, elastic friction part; 84, base body; 9, fixed valve group; 10, locking mechanism; 11, outer cylinder; 111, guide slope; 112, sealing section; 113, positioning end; 12, oil pipe; 13, packer; 14, gas-liquid mixed extraction rod type pump; 15, screen pipe; 16, tail pipe. DETAILED DESCRIPTION

[0043] Clearly, the described embodiments are merely a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts under the premise that no creative efforts are made, belong to the scope of protection of the present application.

[0044] Embodiment 1:

[0045] Please refer to Figure 1 、 Figure 3 The gas-liquid mixed rod pump provided by the present application comprises a pump barrel 5, a plunger body 6 and a pull rod 1. The plunger body 6 is slidingly arranged in the pump barrel 5. The upper end of the pump barrel 5 is provided with a joint 2. The outer wall of the pump barrel 5 is provided with a sealing assembly 4. The inside of the pump barrel 5 is provided with a slide valve 3 above the plunger body 6. The inside of the pump barrel 5 is provided with a fixed valve group 9 below the plunger body 6. The lower end of the pump barrel 5 is connected with a locking mechanism 10. The pull rod 1 passes through the joint 2 and the slide valve 3. The lower end of the pull rod 1 is connected with the upper end of the plunger body 6. The inside of the plunger body 6 is provided with a drainage valve group 7 at the lower end. The lower end of the plunger body 6 is connected with a movable support rod mechanism 8. The movable support rod mechanism 8 can open the first valve ball of the drainage valve group 7 in the downward movement of the plunger body 6.

[0046] Specifically, the pull rod 1 is provided with an anti-falling ring above the joint 2. The outer diameter of the anti-falling ring is greater than the inner diameter of the upper port of the joint 2, so as to prevent the pull rod 1 from falling into the pump barrel 5. The upper end of the pull rod 1 is used for connecting a sucker rod.

[0047] Specifically, the joint 2 comprises a fishing section and a drainage section which are connected in sequence. The outer wall of the fishing section is provided with a fishing step 21. The drainage section is conical downwardly. The drainage section is provided with a first drainage flow channel 22 for draining.

[0048] Specifically, the slide valve 3 comprises a limiting ring and a sliding block. The center of the limiting ring is provided with a second drainage flow channel 22. The limiting ring is connected with the inner wall of the pump barrel 5 through threads. The outer diameter of the sliding block is greater than the caliber of the second drainage flow channel 22. The sliding block can be seated on the limiting ring to block the second drainage flow channel 22. The sliding block is in contact with the drainage section of the joint 2 when the sliding block moves upward. The sliding block cannot block the first drainage flow channel 22. The inner diameter of the sliding block is greater than the outer diameter of the pull rod 1. The sliding block and the pull rod 1 form a gap seal. The roughness of the sliding part of the pull rod 1 and the sliding block is less than Ra3.2.

[0049] Preferably, the sliding block is cylindrical. Since the drainage section of the joint 2 is conical, the sliding block cannot block the first drainage flow channel 22.

[0050] Another preferably, the sliding block upper end surface is provided with a flow guide groove, the flow guide groove extends to the sliding block side wall, so that after the sliding block blocks the first row of liquid flow channel 22, the liquid flow enters the first row of liquid flow channel 22 through the flow guide groove, thereby making the sliding block unable to block the first row of liquid flow channel 22.

[0051] Specifically, the sealing assembly 4 is located above the plunger body 6, and the sliding valve 3 is arranged above the sealing assembly 4.

[0052] Preferably, the sealing assembly 4 is a first leather cup, and the diffusion port of the first leather cup faces upward to prevent backflow of produced liquid.

[0053] Specifically, the plunger body 6 is provided with a third liquid discharge channel 61 at the upper end.

[0054] Specifically, the liquid discharge valve group 7 is a one-way valve, which comprises a first valve ball, a first valve cover and a first valve seat, the lower end of the plunger body 6 is provided with the first valve seat, the center of the first valve seat is provided with a first valve hole, the first valve cover is arranged in the plunger 6, and the first valve ball is arranged between the first valve hole and the first valve cover.

[0055] Specifically, the movable support rod mechanism 8 comprises a base body 84, the center of the base body 84 is through, the outer wall of the base body 84 is provided with an elastic friction piece 83, the elastic friction piece 83 is in interference fit with the pump barrel 5, the upper end of the base body 84 is provided with a jacking rod 81 and a hanging ring 82, the hanging ring 82 is provided with at least two and is uniformly distributed along the circumference of the base body 84, the hanging ring 82 is inserted into the first valve seat for hanging, the base body 84 slides up and down through the hanging ring 82, and the jacking rod 81 can be inserted into the first valve hole to jack up the first valve ball.

[0056] Preferably, the hanging ring 82 is an inverted L-shaped rod, the first valve seat is provided with a hanging hole, the inverted L-shaped rod is inserted into the first valve seat, the horizontal part of the inverted L-shaped rod is hung on the hanging hole, and the hanging ring 82 does not interfere with the first valve ball seated on the first valve seat; during installation, the hanging ring 82 is first installed on the first valve seat, then the hanging ring 82 is connected with the base body 84 through bolts and supports, and then the first valve seat is connected with the plunger body 6, so that the hanging ring 82 and the hanging hole have a smaller assembly gap, thereby reducing the influence of the hanging hole on the produced liquid, and further, during installation of the hanging ring 82, a sealing gasket is provided between the horizontal part of the inverted L-shaped rod and the first valve seat, so that when the horizontal part of the inverted L-shaped rod contacts the first valve seat, the hanging hole can be sealed by the sealing gasket, thereby further reducing the influence of the hanging hole on the produced liquid.

[0057] Preferably, the upper end surface of the jacking rod 81 is an inclined cylindrical surface, and the jacking rod 81 deviates from the axis of the first valve hole, so that when the jacking rod 81 jacks up the first valve ball, there is a lateral pushing force, the first valve ball can quickly separate from the jacking rod 81, and the damage to the first valve ball is reduced.

[0058] Preferably, the elastic friction member 83 is a second leather cup, which provides a reverse force during the upward and downward movement of the plunger body 6, drives the base 84 to move reversely, and realizes the disengagement and lifting of the valve ball. The diffusion port of the second leather cup faces downward, so that the sand in the gap between the plunger body 6 and the pump barrel can pass through when the plunger body 6 moves upward.

[0059] Specifically, the fixed valve group 9 is a conventional fixed valve, which includes a second valve ball, a second valve seat, and a second valve cover. The positional relationship of the structure is clear to those skilled in the art, and will not be discussed in detail.

[0060] Specifically, the locking mechanism 10 is a frustum-shaped tube, and the small-diameter end of the frustum-shaped tube faces downward.

[0061] Embodiment 2:

[0062] Based on Embodiment 1, in combination with Figure 2 , Figure 4 , this embodiment provides an oil extraction pipe 12 column, which includes an oil pipe 12, an outer barrel 11, a screen pipe 15, and a tail pipe 16 connected in sequence from top to bottom. The outer wall of the oil pipe 12 is provided with a packer 13.

[0063] The outer barrel 11 is sequentially provided with a guide slope 111, a sealing section 112, and a positioning end 113 from top to bottom.

[0064] The large-diameter port of the guide slope 111 faces upward, and is used to provide a guide for the gas-liquid mixed extraction rod type pump 14, so that the gas-liquid mixed extraction rod type pump 14 enters the outer barrel 11.

[0065] The sealing section 112 is in interference fit with the sealing assembly 4, and the roughness of the inner wall of the sealing section 112 is less than Ra3.2.

[0066] The positioning end 113 corresponds in shape to the locking mechanism 10. The positioning end 113 cooperates with the locking mechanism 10 to position the gas-liquid mixed extraction rod type pump 14. The tapered cooperation surface can generate a large pre-tightening force after cooperation.

[0067] Embodiment 3:

[0068] Based on Embodiment 2, this embodiment provides a specific use method of the gas-liquid mixed extraction rod type pump 14, which specifically includes the following steps:

[0069] S1, during construction, the oil pipe 12, the outer barrel 11, the screen pipe 15, and the tail pipe 16 connected in sequence are lowered into the well and reach a predetermined position.

[0070] S2, then the sucker rod is connected with the pull rod 1 of the gas-liquid mixed pumping rod type pump 14, the gas-liquid mixed pumping rod type pump 14 is lowered into the well, the guide inclined surface 111 of the outer cylinder 11 can guide the gas-liquid mixed pumping rod type pump 14 into the outer cylinder 11, after the gas-liquid mixed pumping rod type pump 14 collides with the pump, the locking mechanism 10 cooperates with the positioning end 113 of the outer cylinder 11, after positioning, the sealing assembly 4 is located at the sealing section 112 of the outer cylinder 11, and the sealing assembly 4 and the outer cylinder 11 cooperate to maintain the sealing of the upper pressure, the locking force between the locking mechanism 10 and the outer cylinder 11 is more than 5 times the friction force between the plunger body 6 and the pump cylinder 5 when ascending;

[0071] S3, when pumping and discharging fluid, in the upstroke, the pull rod 1 ascends, drives the plunger body 6, the discharge valve group 7 and the movable support rod mechanism 8 ascend together, the movable support rod mechanism 8 moves downward under the friction force between the elastic friction piece 83 and the pump cylinder 5, the first valve ball is closed, the sliding block is driven by the sliding valve 3 under the pressure difference and the pull rod 1 to ascend, and fluid is discharged into the upper part of the gas-liquid mixed pumping rod type pump 14 through the first discharge flow channel 22 of the joint 2;

[0072] When a large amount of gas exists in the pump cylinder 5, the sliding block ascends in time under the sliding friction of the pull rod 1, and the influence of the gas expansion effect is reduced;

[0073] When the pull rod 1 descends, the sliding block descends and sits on the limiting ring, the sliding valve 3 is closed, the pull rod 1 and the plunger body 6 descend, the elastic friction piece 83 of the movable support rod mechanism 8 and the pump cylinder 5 are frictionally connected, and the movable support rod mechanism 8 is driven to move upward under the pressure difference of the elastic friction piece 83, and the ejector rod 81 pushes away the first valve ball of the discharge valve group 7;

[0074] When a large amount of gas exists in the pump, the pressure above the first valve ball is greater than the pressure below the first valve ball, the first valve ball cannot be opened by the pressure difference, the movable support rod mechanism 8 pushes away the first valve ball by the ejector rod 81 by relying on the friction force, so that the gas enters the pump cylinder 5, the gas is effectively discharged, and gas locking is avoided.

[0075] In the application, parts that are not discussed in detail, and the connection modes of the parts in the application all belong to the known technology in the technical field, and can be directly applied without further description.

[0076] In the utility model, the term "a plurality of" refers to two or more than two, unless otherwise explicitly limited. The terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense. For example, "connection" can be fixed connection, can also be detachable connection, or integrally connected. "Connected" can be directly connected, or indirectly connected through an intermediate medium. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0077] In the description of the utility model, it is understood that the terms "upper", "lower", "left", "right", "front", "rear" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the devices or units referred to must have a particular direction, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the utility model.

[0078] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "a specific embodiment" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the utility model. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0079] The above only describes the preferred embodiments of the utility model, and is not used to limit the utility model, and the utility model can have various changes and changes for those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A gas-liquid mixed extraction rod pump, comprising a pump barrel, a plunger body, and a pull rod, the plunger body is slidingly arranged in the pump barrel, a fixed valve group is arranged inside the pump barrel below the plunger body, the lower end of the pull rod is connected with the upper end of the plunger body, and a liquid discharge valve group is arranged at the lower end inside the plunger body, characterized in that, The lower end of the plunger body is slidingly connected with a movable support rod mechanism; The movable support rod mechanism can open the first valve ball of the drainage valve group in the downward movement of the plunger body.

2. The gas-liquid mixed-pumping rod pump according to claim 1, characterized by The drainage valve group comprises a first valve ball and a first valve seat, the lower end of the plunger body is provided with the first valve seat, the center of the first valve seat is provided with a first valve hole, and the first valve ball is arranged in the first valve hole; The movable support rod mechanism comprises a base body, and the center of the base body is through; The outer wall of the base body is provided with an elastic friction part, and the elastic friction part is in interference fit with the pump barrel; The upper end of the base body is provided with a lifting rod and a hanging ring; The hanging ring is provided with at least two and is uniformly distributed along the circumference of the base body; The hanging ring is inserted into the first valve seat, and the hanging ring can be hung with the first valve seat; The base body slides up and down through the hanging ring, and the lifting rod can be inserted into the first valve hole to lift the first valve ball.

3. The gas-liquid mixed-pumping rod pump according to claim 2, characterized by The hanging ring is a reverse L-shaped rod, and the first valve seat is provided with a hanging hole; The reverse L-shaped rod is inserted into the first valve seat, and the horizontal part of the reverse L-shaped rod can be in contact with the upper end surface of the first valve seat to realize hanging; The hanging ring does not interfere with the first valve ball arranged in the first valve seat.

4. The gas-liquid mixed-pumping rod pump according to claim 2, characterized by The upper end surface of the lifting rod is a slanting cylindrical surface, and the lifting rod deviates from the axis of the first valve hole; The elastic friction part is a second leather cup, and the diffusion port of the second leather cup faces downward.

5. The gas-liquid mixed-pumping rod pump according to any one of claims 1 to 4, characterized by The upper end of the pump barrel is provided with a joint, the outer wall of the pump barrel is provided with a sealing assembly, and the lower end of the pump barrel is connected with a locking mechanism; the pull rod passes through the joint.

6. The gas-liquid mixed-pumping rod pump according to claim 5, characterized by The pull rod is provided with an anti-falling ring above the joint, and the outer diameter of the anti-falling ring is greater than the inner diameter of the upper port of the joint.

7. The gas-liquid mixed-pumping rod pump according to claim 5, characterized by The joint comprises a fishing section and a drainage section connected in sequence, the outer wall of the fishing section is provided with a fishing step, the drainage section is conical downwardly, and the drainage section is provided with a first drainage flow channel.

8. The gas-liquid mixed-pumping rod pump according to claim 7, characterized by The inner part of the pump barrel is provided with a sliding valve above the plunger body, and the pull rod passes through the sliding valve; The sliding valve comprises a limiting ring and a sliding block, the center of the limiting ring is provided with a second drainage flow channel, and the limiting ring is connected with the inner wall of the pump barrel; The outer diameter of the sliding block is greater than the diameter of the second drainage flow channel, the sliding block can be arranged on the limiting ring, and the second drainage flow channel is blocked; When the sliding block is in contact with the drainage section of the joint in upward movement, the sliding block cannot block the first drainage flow channel; The inner diameter of the sliding block is greater than the outer diameter of the pull rod, and the sliding block and the pull rod form a gap seal.

9. The gas-liquid mixed-pumping rod pump according to claim 5, characterized by The sealing assembly is a first leather cup, and the diffusion port of the first leather cup faces upward; The locking mechanism is a frustum-shaped tube, and the small-diameter end of the frustum-shaped tube faces downward.

10. An oil extraction string comprising, in order from top to bottom, a tubing, an outer barrel, a screen, and a tailpipe, the outer wall of the tubing being provided with a packer, characterised in that, The outer barrel is provided with the gas-liquid mixed extraction rod type pump of claim 9; The outer barrel comprises a guide inclined surface, a sealing section and a positioning end from top to bottom in sequence, the sealing section is in interference fit with the sealing assembly, the shape of the positioning end corresponds to the locking mechanism, and the positioning end cooperates with the locking mechanism.

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