Drainage gas recovery device for last-stage natural gas well

Abstract

The utility model relates to a water drainage and gas production device for a last-stage natural gas well, which belongs to the technical field of water drainage and gas production, a gas injection pipe is arranged in a gas production oil pipe, the gas injection pipe sequentially penetrates through a gas production tree, an oil pipe head component and a casing head component from top to bottom, and the lower end of the gas injection pipe directly reaches accumulated water in the natural gas well. A surfactant or gas is injected through the gas injection pipe, and the drainage annulus between the gas injection pipe and the gas production oil pipe is used for drainage, so that the foam drainage operation requirement of a last-stage natural gas well is met, and the utilization rate of natural gas resources is effectively improved. Meanwhile, the length of the gas injection pipe can be set according to the water level of accumulated water in the natural gas well, operation is easy and convenient, and safety is good.

Description

Technical Field

[0001] The utility model belongs to the technical field of water drainage and gas production, and in particular relates to a water drainage and gas production device for a terminal natural gas well. Background Art

[0002] As natural gas wells are produced, a certain amount of water and mud seeps out along with the natural gas. As the energy of the natural gas in the formation gradually decays, the water column at the bottom of the well gradually rises. Fracturing can maintain normal production to a certain extent, but this decrease in gas production is accompanied by an increase in water production. As production nears its end, after multiple fracturing stimulations, the natural gas content in the produced natural gas formation is depleted, making it difficult to achieve both drainage and gas production through conventional fracturing procedures. In terminal wells, although some natural gas resources still remain (typically hundreds of thousands to tens of millions of cubic meters), the pressure of the liquid column generated by the accumulated liquid in the wellbore exceeds the reservoir natural gas pressure, preventing the natural gas from entering the wellbore. Even after further fracturing, the energy of the reservoir natural gas is insufficient to lift the water out of the wellbore to the surface. The remaining natural gas resources in the wellbore cannot meet the requirements of gas lift drainage operations. This situation where natural gas resources remain but are difficult to produce due to drainage issues undoubtedly results in a waste of resources. Therefore, a drainage and gas recovery device is needed for terminal natural gas wells. Utility Model Content

[0003] In order to solve the above problems existing in the prior art, the present invention provides a drainage and gas production device for terminal natural gas wells. The technical problems to be solved by the present invention are achieved through the following technical solutions:

[0004] The utility model provides a drainage and gas production device for a terminal natural gas well, which is arranged on a wellhead gas production equipment. The wellhead gas production equipment comprises, from top to bottom, a gas production tree, a tubing head assembly and a casing head assembly. The drainage and gas production device comprises: an injection pipe, which passes through the gas production tree, the tubing head assembly and the casing head assembly from top to bottom; the injection pipe is coaxially arranged in the gas production oil pipe, and a drainage annulus is formed between the injection pipe and the gas production oil pipe; the injection pipe comprises: a plurality of injection pipe units, which are coaxially arranged in sequence and threadedly connected; a lifting and injection device is arranged on the gas production tree and connected to the injection pipe, and is used to assemble or disassemble a plurality of injection pipe units and lift or lower the injection pipe as a whole; a blowout prevention component comprises: a top wellhead valve and a bottom one-way valve; the top wellhead valve is arranged at the upper end of the injection pipe, and the bottom one-way valve is arranged at the lower end of the injection pipe, both of which are used to prevent natural gas in the natural gas well from spraying out from the injection pipe.

[0005] In one embodiment of the present invention, the lifting injection equipment includes: a lowering and lifting gas injection pipe assembly, a suspension assembly, a sealing assembly and a blowout preventer box assembly; the lowering and lifting gas injection pipe assembly, the suspension assembly, the sealing assembly and the blowout preventer box assembly are arranged in sequence from top to bottom and are respectively connected to the gas injection pipe; wherein, the lowering and lifting gas injection pipe assembly is used to assemble or disassemble several gas injection pipe units and lift or lower the gas injection pipe from the natural gas well; the suspension assembly is used to suspend the gas injection pipe; the sealing assembly is used to seal the outside of the gas injection pipe; the blowout preventer box assembly is used to prevent the natural gas in the natural gas well from being sprayed out from the outside of the gas injection pipe.

[0006] In one embodiment of the present invention, the blowout preventer assembly further includes: a rubber seal, which is arranged between the inner end face of the top wellhead valve and the end face of the gas injection pipe unit at the upper end of the gas injection pipe, and is used to seal the top wellhead valve and the gas injection pipe.

[0007] In one embodiment of the present invention, the rubber sealing member is an inner V-shaped rubber sealing ring, an inner U-shaped rubber sealing ring or an O-shaped rubber sealing ring.

[0008] In one embodiment of the present invention, the top wellhead valve is a ball valve or a needle-type stop valve.

[0009] In one embodiment of the present invention, the size of the gap of the drainage annulus ranges from 10 to 18 mm.

[0010] Compared with the prior art, the beneficial effects of the present invention are:

[0011] The utility model is a drainage and gas production device for terminal natural gas wells. By lifting the injection equipment, a gas injection pipe is lowered into the gas production oil pipe. The gas injection pipe is connected in sequence using a plurality of gas injection pipe units without couplings. The gas injection pipe units are connected by threads. The lower end of the gas injection pipe is provided with a one-way valve, and the upper end of the gas injection pipe is provided with a wellhead valve, ensuring the safety of the gas injection pipe lowering and gas injection and drainage operations. The lower end of the gas injection pipe directly reaches the natural gas well, and surfactant or injection gas is injected through the gas injection pipe. The drainage is carried out using the drainage annulus between the gas injection pipe and the gas production oil pipe. This meets the requirements of the foam drainage operation of terminal natural gas wells and effectively improves the utilization rate of natural gas resources.

[0012] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In addition, in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1This is a structural diagram of a drainage and gas production device for a terminal natural gas well provided by an embodiment of the present utility model;

[0014] Figure 2 This is a structural diagram of a lifting and injection device provided by an embodiment of the present utility model;

[0015] Figure 3 The embodiment of the present utility model provides Figure 2 A partial enlarged view of point A in the middle;

[0016] Figure 4 It is a structural schematic diagram of the gas injection pipe provided by an embodiment of the utility model.

[0017] Icons: 1- Christmas tree; 10- Production tubing; 20- Production casing; 2- Tubing head assembly; 3- Casing head assembly; 100- Injection pipe; 200- Lifting injection equipment; 210- Running and lifting injection pipe assembly; 220- Suspension assembly; 230- Seal assembly; 240- BOP assembly; 300- BOP assembly; 310- Top wellhead valve; 320- Bottom check valve; 330- Rubber seal. DETAILED DESCRIPTION

[0018] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the present invention, the following is a detailed description of a drainage and gas production device for a terminal natural gas well proposed according to the present invention in combination with the accompanying drawings and specific implementation methods.

[0019] The aforementioned and other technical contents, features, and effects of the present invention are clearly presented in the following detailed description of the specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and specific understanding of the technical means and effects adopted by the present invention to achieve the intended purpose can be obtained. However, the accompanying drawings are for reference and illustration purposes only and are not intended to limit the technical solutions of the present invention.

[0020] Example 1

[0021] like Figure 1 As shown, the utility model provides a drainage gas production device for terminal natural gas wells, which is arranged on a wellhead gas production equipment, wherein the wellhead gas production equipment includes, from top to bottom, a gas tree 1, a tubing head assembly 2 and a casing head assembly 3.

[0022] In this embodiment, if Figure 1 and Figure 2As shown, the drainage gas production device for terminal natural gas wells of this embodiment includes: a gas injection pipe 100 and a lifting injection device 200; wherein, the gas injection pipe 100 passes through the gas tree 1, the oil tubing head assembly 2 and the casing head assembly 3 from top to bottom; the lifting injection device 200 is arranged on the gas tree 1 and connected to the gas injection pipe 100, and is used to assemble or disassemble several gas injection pipe units and lift or lower the gas injection pipe 100 as a whole.

[0023] In this embodiment, the gas injection pipe 100 is coaxially disposed in the gas production tubing 10 , and a drainage annulus is formed between the gas injection pipe 100 and the gas production tubing 10 .

[0024] Exemplarily, the size of the gap of the drainage annulus ranges from 10 to 18 mm.

[0025] As can be understood, because the injection pipe 100 is installed within the production tubing 10, the width of the drainage annulus formed between the injection pipe 100 and the production tubing 10 is smaller than the width and area of ​​the annulus formed between the production casing 20 and the production tubing 10. Furthermore, because the lower end of the injection pipe 100 extends deep into the accumulated water in the natural gas well, adjusting the length of the injection pipe 100 simultaneously facilitates both gas injection and drainage operations. In other words, compared to a large annulus, a small annulus has a greater liquid-carrying capacity.

[0026] In this embodiment, if Figure 3 As shown, the gas injection pipe 100 includes: a plurality of gas injection pipe units, and the plurality of gas injection pipe units are coaxially arranged in sequence and threadedly connected.

[0027] In an optional embodiment, the lifting injection equipment 200 includes: a lowering and lifting gas injection pipe assembly 210, a suspension assembly 220, a sealing assembly 230 and a blowout preventer box assembly 240; the lowering and lifting gas injection pipe assembly 210, the suspension assembly 220, the sealing assembly 230 and the blowout preventer box assembly 240 are arranged in sequence from top to bottom and are respectively connected to the gas injection pipe 100; wherein, the lowering and lifting gas injection pipe assembly 210 is used to assemble or disassemble several gas injection pipe units and lift or lower the gas injection pipe 100 from the natural gas well; the suspension assembly 220 is used to suspend the gas injection pipe 100; the sealing assembly 230 is used to seal the outside of the gas injection pipe 100; the blowout preventer box assembly 240 is used to prevent the natural gas in the natural gas well from being sprayed out from the outside of the gas injection pipe 100 when the sealing assembly 230 fails to seal.

[0028] like Figures 1 to 4As shown, the drainage and gas production device for the terminal natural gas well of this embodiment also includes: a blowout prevention assembly 300; the blowout prevention assembly 300 includes: a top wellhead valve 310 and a bottom one-way valve 320; the top wellhead valve 310 is arranged at the upper end of the gas injection pipe 100, and the bottom one-way valve 320 is arranged at the lower end of the gas injection pipe 100, both of which are used to prevent the natural gas in the natural gas well from being sprayed out from the gas injection pipe 100.

[0029] It is worth noting that several gas injection pipe units all adopt a non-coupling structure, and adjacent gas injection pipe units are connected by threads, which is not only conducive to reducing the total weight of the gas injection pipe 100, but also conducive to connecting the gas injection pipe units by lifting the injection equipment 200, thereby improving work efficiency. In addition, a bottom one-way valve 320 is provided in the gas injection pipe unit at the lowest end to ensure that the gas flow path in the gas injection pipe 100 is one-way, that is, when the pipe is lowered and pressurized nitrogen or air is injected from top to bottom, natural gas or injected gas is prevented from flowing back along the gas injection pipe 100, thereby improving safety. Furthermore, two bottom one-way valves 320 are provided in series in the gas injection pipe unit at the lowest end. When one of the bottom one-way valves 320 fails (such as seal failure), the other bottom one-way valve 320 can still work normally, further improving reliability. Furthermore, the two bottom one-way valves 320 can also be respectively arranged in different gas injection pipe units, and it is only necessary to ensure that the conduction paths of the two bottom one-way valves 320 are both conducted from top to bottom and sealed from bottom to top.

[0030] On this basis, if Figures 2 to 4 As shown, a top wellhead valve 310 is provided in the uppermost gas injection pipe unit, corresponding to a bottom one-way valve 320. The bottom one-way valve 320 serves as a passive safety structure, while the top wellhead valve 310 serves as an active safety structure. Manually closing the top wellhead valve 310 further ensures safety during the lowering of the gas injection pipe 100 and during gas injection. As can be understood, taking the lowering operation as an example, the lowermost gas injection pipe unit is first lowered into the natural gas well. At this time, there is a risk of sealing failure of the bottom one-way valve 320. The opening and closing of the top wellhead valve 310 are both manually controlled, and the opening degree of the top wellhead valve 310 can also be linear. Therefore, by gradually opening the top wellhead valve 310, the sealing performance of the bottom one-way valve 320 can be verified, thereby improving operational safety and controllability.

[0031] Illustratively, the top wellhead valve 310 may be a ball valve or a needle-type stop valve.

[0032] In an optional embodiment, if Figure 2 and Figure 3As shown, the blowout preventer assembly 300 also includes: a rubber seal 330, which is arranged close to the top wellhead valve 310 between the inner end face of the top wellhead valve 310 and the end face of the gas injection pipe unit at the upper end of the gas injection pipe 100, and is used to seal the top wellhead valve 310 and the gas injection pipe 100.

[0033] Exemplarily, the rubber seal 330 may be an inner V-shaped rubber seal ring, an inner U-shaped rubber seal ring, or an O-shaped rubber seal ring.

[0034] The utility model is a drainage and gas production device for terminal natural gas wells. By lifting the injection equipment, a gas injection pipe is lowered into the gas production oil pipe. The gas injection pipe is connected in sequence using a plurality of gas injection pipe units without couplings. The gas injection pipe units are connected by threads. The lower end of the gas injection pipe is provided with a one-way valve, and the upper end of the gas injection pipe is provided with a wellhead valve, ensuring the safety of the gas injection pipe lowering and gas injection and drainage operations. The lower end of the gas injection pipe directly reaches the natural gas well, and surfactant or injection gas is injected through the gas injection pipe. The drainage is carried out using the drainage annulus between the gas injection pipe and the gas production oil pipe. This meets the requirements of the foam drainage operation of terminal natural gas wells and effectively improves the utilization rate of natural gas resources.

[0035] It should be noted that, in this document, relational terms such as first and second are used solely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, the terms "comprise," "include," or any other variations thereof are intended to encompass non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not explicitly listed. Without further limitation, elements defined by the phrase "comprising a..." do not preclude the presence of additional identical elements in the article or device comprising the elements. Terms such as "connected" or "connected" are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. References to directions or positional relationships, such as "upper," "lower," "left," and "right," are based on the directions or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplification of the present invention. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention.

[0036] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A drainage gas production device for a terminal natural gas well, which is installed on a wellhead gas production device. The wellhead gas production device comprises, from top to bottom: A gas production tree (1), a tubing head assembly (2) and a casing head assembly (3), characterized in that the water drainage gas production device comprises: The gas injection pipe (100) passes through the gas tree (1), the tubing head assembly (2) and the casing head assembly (3) in sequence from top to bottom; the gas injection pipe (100) is coaxially arranged in the gas production oil pipe (10), and a drainage annulus is formed between the gas injection pipe (100) and the gas production oil pipe (10); the gas injection pipe (100) comprises: a plurality of gas injection pipe units, the plurality of gas injection pipe units are coaxially arranged in sequence and threadedly connected; A lifting injection device (200) is provided on the gas tree (1) and connected to the gas injection pipe (100), and is used for assembling or disassembling the plurality of gas injection pipe units and lifting or lowering the gas injection pipe (100) as a whole; The blowout prevention assembly (300) comprises a top wellhead valve (310) and a bottom one-way valve (320); the top wellhead valve (310) is arranged at the upper end of the gas injection pipe (100), and the bottom one-way valve (320) is arranged at the lower end of the gas injection pipe (100), both of which are used to prevent natural gas in a natural gas well from being ejected from the gas injection pipe (100).

2. The drainage and gas production device for terminal natural gas wells according to claim 1, characterized in that: The lifting injection device (200) comprises: a lowering and lifting air injection pipe assembly (210), a suspension assembly (220), a sealing assembly (230) and a blowout prevention box assembly (240); the lowering and lifting air injection pipe assembly (210), the suspension assembly (220), the sealing assembly (230) and the blowout prevention box assembly (240) are arranged in sequence from top to bottom and are respectively connected to the air injection pipe (100); The lowering and lifting gas injection pipe assembly (210) is used to assemble or disassemble the plurality of gas injection pipe units and to lift or lower the gas injection pipe (100) from the natural gas well; the hanging assembly (220) is used to hang the gas injection pipe (100); the sealing assembly (230) is used to seal the outside of the gas injection pipe (100); and the blowout prevention box assembly (240) is used to prevent the natural gas in the natural gas well from being sprayed out from the outside of the gas injection pipe (100).

3. The drainage and gas production device for terminal natural gas wells according to claim 1, characterized in that: The blowout prevention assembly (300) further comprises a rubber seal (330), which is arranged between the inner end surface of the top wellhead valve (310) and the end surface of the gas injection pipe unit at the upper end of the gas injection pipe (100) and is used to seal the top wellhead valve (310) and the gas injection pipe (100).

4. The drainage and gas production device for terminal natural gas wells according to claim 3, characterized in that: The rubber seal (330) is an inner V-shaped rubber seal ring, an inner U-shaped rubber seal ring or an O-shaped rubber seal ring.

5. The drainage and gas production device for terminal natural gas wells according to claim 1, characterized in that: The top wellhead valve (310) is a ball valve or a needle-type stop valve.

6. The drainage and gas production device for terminal natural gas wells according to claim 1, characterized in that: The size range of the gap of the drainage annulus is: 10 to 18 mm.

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