A sealing system for a drainage gas recovery ram

Abstract

The application relates to a sealing system for a drainage gas recovery plunger. The sealing system comprises a center body, an elastic sealing assembly sleeved on the center body, the elastic sealing assembly comprising a first reset elastic member and a sealing body, the sealing body being used for pressing on the inner wall of the oil pipe under the action of the first reset elastic member, a rubber sleeve sleeved on the center body, the rubber sleeve and the center body surrounding an annular cavity, a pressure transmission channel arranged on the center body, one end of the pressure transmission channel being communicated with the annular cavity, the other end of the pressure transmission channel being below the elastic sealing assembly and being communicated with the outside of the center body, a one-way valve arranged on the pressure transmission channel, the one-way valve comprising a valve core and a second reset elastic member, the second reset elastic member being used for applying an elastic force to the valve core to make the valve core close the pressure transmission channel, the valve core being provided with a pressure relief hole extending through in the axial direction of the valve core, and the center body being provided with a center flow channel, the center body being provided with a flow channel valve for controlling the opening and closing of the center flow channel.

Description

TECHNICAL FIELD

[0001] The present application relates to a sealing system for a water drainage gas recovery plunger. BACKGROUND

[0002] In the process of water-bearing gas well production, liquid loading will occur in the wellbore. For high-pressure gas wells, wellbore liquid loading will waste formation energy and limit the production capacity of the gas well. For low-pressure gas wells, wellbore liquid loading can completely kill the gas well, causing water flooding and well shut-in, resulting in reduced production or production stoppage of the gas well. To ensure normal production of the gas well, wellbore liquid loading must be promptly discharged.

[0003] Plunger gas lift drainage is widely used as a simple and effective method of water drainage gas recovery. The principle is to use formation pressure to rapidly separate gas and liquid at the sealing interface of the plunger, and to use the lifting gas in the downhole to push the plunger and the liquid column at the upper end to the wellhead, thereby discharging the liquid loading and extending the production time of the gas well.

[0004] A gasket type water drainage gas recovery plunger is disclosed in Chinese patent document CN104389782A, which includes an upper sealing body group and a lower sealing body group. Each sealing body group includes a sealing body (i.e., a gasket) and a spring. Under the action of the spring, the sealing body tightly adheres to the inner wall of the oil pipe. When the plunger is ascending, it avoids gas slip and liquid backflow. When the oil pipe diameter changes, the plunger can smoothly pass through the oil pipe diameter change by compressing the spring through the sealing body. The sealing body and the spring constitute an elastic sealing assembly.

[0005] In the prior art, the plunger needs to be suspended in the well for pressure build-up before ascending to ensure sufficient lifting pressure. In the above patent document, the sealing body and the oil pipe inner wall are in rigid contact, and the sealing performance is relatively poor. When the pressure difference between the upper and lower pressures reaches a certain pressure value, it is easy to release pressure between the sealing body and the oil pipe inner wall, and it is not easy to ensure sufficient lifting pressure. SUMMARY

[0006] The purpose of the present application is to provide a sealing system for a water drainage gas recovery plunger to solve the technical problem in the prior art that when the pressure difference between the upper and lower pressures reaches a certain pressure value, it is easy to release pressure between the sealing body and the oil pipe inner wall.

[0007] To achieve the above purpose, the technical scheme of the sealing system for the water drainage gas recovery plunger of the present application is as follows:

[0008] The sealing system for the drainage gas recovery plunger comprises a center body, an elastic sealing assembly is sleeved on the center body, the elastic sealing assembly comprises a first reset elastic member and a sealing body, the sealing body is used for pressing on the inner wall of the oil pipe under the action of the first reset elastic member, a rubber sleeve is also sleeved on the center body, the rubber sleeve and the center body enclose an annular cavity, a pressure transmission channel is arranged on the center body, one end of the pressure transmission channel is communicated with the annular cavity, the other end of the pressure transmission channel is below the elastic sealing assembly and is communicated with the outside of the center body, a one-way valve is arranged on the pressure transmission channel, the one-way valve comprises a valve core and a second reset elastic member, the second reset elastic member is used for applying an elastic force to the valve core to close the pressure transmission channel, a pressure relief hole is arranged on the valve core and extends through the valve core in the axial direction, and the center body has a center flow channel and is provided with a flow channel valve for controlling the opening and closing of the center flow channel.

[0009] The rubber sleeve remains unchanged when the drainage gas recovery plunger is descending, the elastic sealing assembly can protect the rubber sleeve and prevent the rubber sleeve from rubbing against the inner wall of the oil pipe, the flow channel valve is closed in the well when the plunger is pressurized in the well, the pressure transmission channel continuously fills the high-pressure gas in the well into the annular cavity at this time, the rubber sleeve expands radially and is tightly attached to the inner wall of the oil pipe to form a seal, the sealing performance of the rubber sleeve and the inner wall of the oil pipe is good due to the softness of the rubber sleeve, and sufficient lifting pressure is ensured. During the ascending process, the rubber sleeve returns to the original state due to its elasticity after the pressure inside and outside the rubber sleeve reaches balance, the gas in the annular cavity is slowly discharged through the pressure relief hole, and the rubber sleeve no longer rubs against the inner wall of the oil pipe. In addition, the rubber sleeve can reduce the friction with the inner wall of the oil pipe, reduce the risk of damage to the rubber sleeve, and prolong the service life of the rubber sleeve.

[0010] As a further improvement, the center body is provided with a pressure transmission pipe, and a lumen of the pressure transmission pipe constitutes the pressure transmission channel.

[0011] The pressure transmission pipe is convenient to arrange on the center body, and is conducive to the formation of the pressure transmission channel.

[0012] As a further improvement, the elastic sealing assembly is provided with two groups, and the rubber sleeve is located between the two groups of elastic sealing assemblies.

[0013] The sealing performance of the plunger is further ensured.

[0014] As a further improvement, the center body comprises an upper cylinder body and a lower cylinder body, the two groups of elastic sealing assemblies are sleeved on the upper cylinder body and the lower cylinder body respectively, the lower cylinder body is provided with an annular step, the rubber sleeve is sleeved on the lower cylinder body, one end of the rubber sleeve abuts against the annular step, and the other end of the rubber sleeve abuts against the lower end surface of the upper cylinder body.

[0015] The rubber sleeve is convenient to install and position.

[0016] As a further improvement, the valve core is screw-shaped structure, and an annular rubber pad is sleeved on the valve core.

[0017] The beneficial effect is that: in this way, the valve core can guide itself to ensure that the valve core does not deviate when reciprocating in the pressure transmission channel.

[0018] As a further improvement, the second reset elastic member is a reset compression spring.

[0019] As a further improvement, each sealing body corresponds to at least two first reset elastic members.

[0020] The beneficial effect is that: in this way, the sealing body can be stably pressed against the inner wall of the oil pipe.

[0021] As a further improvement, the sealing body is arranged in a plurality of circumferential directions of the center body, and one of any two adjacent sealing bodies is provided with an elastic sheet on the inner side below, and the width of the elastic sheet in the circumferential direction of the center body is greater than the gap between the two adjacent sealing bodies.

[0022] As a further improvement, the flow channel valve is arranged at the lower part of the center body, and the flow channel valve comprises an outer cylinder and an inner cylinder, the cylinder wall of the outer cylinder and the inner cylinder is provided with a flow channel port, the outer cylinder is connected to the lower part of the center body, and the inner cylinder is rotatably assembled in the outer cylinder.

[0023] The beneficial effect is that: in this way, the flow channel port can be designed larger to increase the flow area.

[0024] As a further improvement, the flow channel valve is arranged at the lower part of the center body, and the flow channel valve comprises an outer cylinder and an inner cylinder, the cylinder wall of the outer cylinder and the inner cylinder is provided with a flow channel port, the outer cylinder is connected to the lower part of the center body, and the inner cylinder is rotatably assembled in the outer cylinder.

[0025] The beneficial effect is that: in this way, the flow channel port can be designed larger to increase the flow area. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The structure diagram of the sealing system for the water drainage and gas recovery plunger of the application;

[0027] Figure 2 The structure diagram of the sealing system for the water drainage and gas recovery plunger of the application; Figure 1 The structure diagram of the sealing system for the water drainage and gas recovery plunger of the application;

[0028] Figure 3 The structure diagram of the sealing system for the water drainage and gas recovery plunger of the application; Figure 2 The structure diagram of the sealing system for the water drainage and gas recovery plunger of the application;

[0029] Figure 4 The structure diagram of the sealing system for the water drainage and gas recovery plunger of the application; Figure 1 The structure diagram of the sealing system for the water drainage and gas recovery plunger of the application;

[0030] In the figure: 41, upper cylinder; 42, upper limit sleeve; 43, compression spring positioning groove; 44, lower limit sleeve; 45, rubber cylinder; 46, annular cavity; 47, lower cylinder; 48, flow channel valve; 49, first reset compression spring; 50, sealing body; 51, pressure transmission pipe; 52, check valve; 53, limiting protrusion; 54, elastic sheet; 55, second reset compression spring; 56, valve core; 57, annular rubber gasket; 58, pressure relief hole. DETAILED DESCRIPTION

[0031] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application, that is, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application generally described and shown in the drawings can be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] It should be noted that the relational terms such as "first" and "second" and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of additional identical elements in the process, method, article or device including the element. In addition, the terms "front", "back", "up", "down", "left", "right" are based on the orientation and positional relationship shown in the drawings, and are only for the convenience of describing the present application, and do not indicate that the devices or components referred to must have a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0034] The features and properties of the present application are further described in detail below in conjunction with the embodiments.

[0035] Embodiment 1 of the sealing system for the water drainage gas recovery plunger of the present application:

[0036] AsFigure 1 As shown, the sealing system for the drainage and gas extraction plunger includes a central body, which is a cylindrical structure formed by an upper cylinder 41 and a lower cylinder 47 threaded together. The inner cavities of the two cylinders form a central flow channel. Elastic sealing components are respectively fitted onto the upper cylinder 41 and the lower cylinder 47. A rubber sleeve 45 is also fitted onto the lower cylinder 47, positioned between the two sets of elastic sealing components. In other embodiments, the rubber sleeve may be positioned above the elastic sealing components on the upper cylinder.

[0037] In this embodiment, the lower cylinder 47 is provided with an annular step, the lower end of the rubber tube 45 abuts against the annular step, and the upper end of the rubber tube 45 abuts against the lower end face of the upper cylinder 41, so as to facilitate the installation of the rubber tube 45.

[0038] In this embodiment, the two sets of elastic sealing assemblies have the same structure. Taking the upper elastic sealing assembly as an example, the upper end of the upper cylinder 41 is threadedly connected to an upper limit sleeve 42, and the lower part of the upper limit sleeve 42 and the upper cylinder 41 form an upper limit annular groove; the lower end of the upper cylinder 41 is threadedly connected to a lower limit sleeve 44, and the upper part of the lower limit sleeve 44 and the upper cylinder 41 form a lower limit annular groove. The elastic sealing assembly includes a first reset spring 49 and a sealing body 50. Under the action of the first reset spring 49, the sealing body 50 is used to press against the inner wall of the oil pipe; as Figure 2 and Figure 3 As shown, four sealing bodies 50 are arranged circumferentially along the upper cylinder 41. Each sealing body 50 has a limiting protrusion 53 at both ends. The two limiting protrusions 53 of the sealing body 50 are respectively limited and assembled in the upper limiting ring groove and the lower limiting ring groove, so that the sealing body 50 floats and is assembled on the upper cylinder 41.

[0039] In this embodiment, each sealing body 50 corresponds to two first reset springs 49, and the two first reset springs 49 are arranged axially spaced along the upper cylinder 41 to ensure that the sealing body 50 can stably press against the inner wall of the oil pipe. The first reset springs 49 constitute the first reset elastic element. In other embodiments, each sealing body may correspond to one or more first reset springs.

[0040] like Figure 1 As shown, both the sealing body 50 and the upper cylinder 41 are provided with spring positioning grooves 43. The spring positioning grooves 43 are arranged corresponding to the first reset spring 49. The outer end of the first reset spring 49 is located in the spring positioning groove 43 on the sealing body 50, and the inner end of the first reset spring 49 is located in the spring positioning groove 43 on the upper cylinder 41, so as to ensure the stability of the first reset spring 49 during the extension and retraction process.

[0041] like Figure 2 and Figure 3As shown, the inner side of one of the two adjacent sealing bodies 50 is provided with an elastic sheet 54, the width of the elastic sheet 54 along the circumference of the center body is greater than the gap between the two adjacent sealing bodies 50, so as to reduce the leakage of liquid from the inside of the sealing body 50 along the axial direction of the upper cylinder body 41, and the elastic sheet 54 can be tightly attached to the inner side of the sealing body 50 to further reduce the leakage.

[0042] As shown in Figure 1 and Figure 4 The rubber cylinder 45 and the upper cylinder body 41 form an annular cavity 46, and the lower cylinder body 47 is provided with a pressure transmission pipe 51, the lumen of the pressure transmission pipe 51 forms a pressure transmission channel, one end of the pressure transmission channel is in communication with the annular cavity 46, and the other end of the pressure transmission channel is below the elastic sealing assembly on the lower cylinder body 47 and is in communication with the outside of the center body. Wherein, when the annular cavity 46 does not enter high-pressure gas, the outer diameter of the rubber cylinder 45 is smaller than the outer diameter of the elastic sealing assembly.

[0043] In this embodiment, the pressure transmission channel is provided with a one-way valve 52, the one-way valve 52 includes a valve core 56 and a second reset compression spring 55, the second reset compression spring 55 is used to apply an elastic force to the valve core 56 to close the pressure transmission channel; the valve core 56 is provided with a pressure relief hole 58, the pressure relief hole 58 extends through the valve core 56 in the axial direction. Wherein, the second reset compression spring 55 constitutes a second reset elastic member.

[0044] In this embodiment, the valve core 56 is a screw-shaped structure, and an annular rubber pad 57 is sleeved on the valve core 56 to ensure the sealing performance.

[0045] As shown in Figure 1 The lower part of the lower cylinder body 47 is provided with a flow channel valve 48, the flow channel valve 48 includes an outer cylinder and an inner cylinder, the cylinder wall of the outer cylinder and the inner cylinder is provided with a flow channel port, the outer cylinder is connected to the lower part of the lower cylinder body 47, and the inner cylinder is driven by a drive motor (not shown) below it to rotate and be assembled in the outer cylinder. The specific structure and working principle of the above-mentioned flow channel valve are prior art, which will not be described in detail here.

[0046] When the drainage gas recovery plug is descending, the rubber sleeve 45 remains unchanged, and the elastic sealing assembly can protect the rubber sleeve 45 well, because the diameter of the elastic sealing assembly is larger than that of the rubber sleeve 45, so that the rubber sleeve 45 is prevented from rubbing against the inner wall of the oil pipe; when the plug is pressurized in the well, the flow valve 48 is closed in the well, at this time, the pressure transmission pipe 51 continuously fills the high-pressure gas in the annular cavity 46, so that the rubber sleeve 45 expands radially and is tightly attached to the inner wall of the oil pipe to form a seal, because the rubber sleeve 45 is soft, the sealing performance of the rubber sleeve 45 and the inner wall of the oil pipe is good, and sufficient lifting pressure is ensured. During the ascending process, when the internal and external pressures of the rubber sleeve 45 reach balance, the rubber sleeve 45 needs to restore the original shape due to its elasticity, so that the gas in the annular cavity 46 is slowly discharged through the pressure relief hole 58, and then the rubber sleeve 45 no longer rubs against the inner wall of the oil pipe. In addition, the rubber sleeve can reduce the friction with the inner wall of the oil pipe, reduce the risk of rubber sleeve damage, and prolong the service life of the rubber sleeve.

[0047] Embodiment 2 of the sealing system for the drainage gas recovery plug of the present application:

[0048] The difference between this embodiment and embodiment 1 is that, in embodiment 1, the lower cylinder 47 is provided with the pressure transmission pipe 51, and the lumen of the pressure transmission pipe 51 constitutes the pressure transmission channel. In this embodiment, the lower cylinder is processed with a pressure transmission groove, and the groove opening of the pressure transmission groove is welded with a cover, and the groove cavity of the pressure transmission groove constitutes the pressure transmission channel.

[0049] Embodiment 3 of the sealing system for the drainage gas recovery plug of the present application:

[0050] The difference between this embodiment and embodiment 1 is that, in embodiment 1, the elastic sealing assembly is provided with two groups, and the rubber sleeve 45 is between the two groups of elastic sealing assemblies. In this embodiment, the elastic sealing assembly is provided with one group, and the rubber sleeve is above the elastic sealing assembly.

[0051] Embodiment 4 of the sealing system for the drainage gas recovery plug of the present application:

[0052] The difference between this embodiment and embodiment 1 is that, in embodiment 1, the valve core 56 is a screw structure, and the annular rubber pad 57 is sleeved on the valve core 56 to ensure the sealing performance. In this embodiment, the valve core is a conical structure.

[0053] Embodiment 5 of the sealing system for the drainage gas recovery plug of the present application:

[0054] The difference between the present embodiment and embodiment 1 is that in embodiment 1, the flow passage valve 48 comprises an outer cylinder and an inner cylinder, the cylinder wall of the outer cylinder and the inner cylinder is provided with a flow passage port, the outer cylinder is connected to the lower part of the lower cylinder body 47, and the inner cylinder is driven by a driving motor (not shown) below it to rotate and be assembled in the outer cylinder. In the present embodiment, the flow passage valve comprises an outer cylinder and an inner cylinder, the cylinder wall of the outer cylinder and the inner cylinder is provided with a flow passage port, the outer cylinder is connected to the lower part of the center body, and the inner cylinder is driven by a driving motor below it to be axially guided and slidably assembled in the outer cylinder.

[0055] The above is only a preferred embodiment of the present application and is not intended to limit the present application. The patent protection scope of the present application is subject to the claims, and any equivalent structural changes made by using the content of the specification and drawings should also be included in the protection scope of the present application.

Claims

1. A sealing system for a water drainage gas production plunger, comprising a center body, an elastic sealing assembly being sleeved on the center body, the elastic sealing assembly comprising a first reset elastic member and a sealing body (50), the sealing body (50) being used for pressing on the inner wall of the oil pipe under the action of the first reset elastic member; characterized in that, The center body is further sleeved with a rubber cylinder (45), the rubber cylinder (45) and the center body form an annular cavity (46), the center body is provided with a pressure transmission channel, one end of the pressure transmission channel communicates with the annular cavity (46), the other end of the pressure transmission channel is below the elastic sealing assembly and communicates with the outside of the center body, the pressure transmission channel is provided with a one-way valve (52), the one-way valve (52) comprises a valve core (56) and a second reset elastic member, the second reset elastic member is used for applying an elastic force to the valve core (56) to close the pressure transmission channel, the valve core (56) is provided with a pressure relief hole (58), the pressure relief hole (58) extends through in the axial direction of the valve core (56), the center body has a center flow channel, the center body is provided with a flow channel valve (48), the flow channel valve (48) is used for controlling the opening and closing of the center flow channel, the elastic sealing assembly is provided with two groups, the rubber cylinder (45) is between the two groups of elastic sealing assemblies, the center body comprises an upper cylinder body (41) and a lower cylinder body (47), the two groups of elastic sealing assemblies are sleeved on the upper cylinder body (41) and the lower cylinder body (47) respectively, the lower cylinder body (47) is provided with an annular step, the rubber cylinder (45) is sleeved on the lower cylinder body (47), one end of the rubber cylinder (45) abuts on the annular step, the other end of the rubber cylinder (45) abuts on the lower end face of the upper cylinder body (41).

2. The drainage gas recovery plunger seal system of claim 1, wherein, The center body is provided with a pressure transmission pipe (51), the pipe cavity of the pressure transmission pipe (51) constitutes the pressure transmission channel.

3. The seal system for a water drainage gas recovery plunger of claim 1 or 2, wherein, The valve core (56) is a screw-shaped structure, and an annular rubber pad (57) is sleeved on the valve core (56).

4. The seal system for a water drainage gas recovery plunger of claim 1 or 2, wherein, The second reset elastic member is a reset compression spring.

5. The seal system for a water drainage gas recovery plunger of claim 1 or 2, wherein, Each sealing body (50) corresponds to at least two first reset elastic members.

6. The seal system for a water drainage gas recovery plunger of claim 1 or 2, wherein, The sealing body (50) is arranged in the circumferential direction of the center body, and one of any two adjacent sealing bodies (50) is provided with an elastic sheet (54) below the inner side, the width of the elastic sheet (54) in the circumferential direction of the center body is greater than the gap between the two adjacent sealing bodies (50).

7. The seal system for a water drainage gas recovery ram as claimed in claim 1 or 2, wherein, The flow channel valve (48) is arranged at the lower part of the center body, the flow channel valve (48) comprises an outer cylinder and an inner cylinder, the cylinder wall of the outer cylinder and the inner cylinder is provided with a flow channel opening, the outer cylinder is connected to the lower part of the center body, and the inner cylinder is rotationally assembled in the outer cylinder.

8. The seal system for a water drainage gas recovery ram as claimed in claim 1 or 2, wherein, The flow channel valve (48) is arranged at the lower part of the center body, the flow channel valve (48) comprises an outer cylinder and an inner cylinder, the cylinder wall of the outer cylinder and the inner cylinder is provided with a flow channel opening, the outer cylinder is connected to the lower part of the center body, and the inner cylinder is rotationally assembled in the outer cylinder.

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