Gas injection balance valve and gas injection tubular column

Abstract

The utility model relates to the field of extracting oil from a well by utilizing heat energy, in particular to a gas injection balance valve and a gas injection tubular column. A gas injection pipe column comprises an oil pipe, a gas injection balance valve is connected to the oil pipe in series, the gas injection balance valve comprises a shell, a vertically-through gas injection channel is formed in the shell, a valve body assembly is further arranged in the shell, and the valve body assembly is provided with a gas inlet channel with one end communicated with the gas injection channel and the other end communicated with a casing annulus on the outer side of the shell. The one-way valve is used for allowing high-pressure steam in the casing annulus to enter and flow into the gas injection channel when the pressure in the casing annulus reaches the set pressure, and the problem that in the prior art, when gas injection is conducted, water in the casing annulus is heated and evaporated, the pressure in the casing annulus is too large, and then a gas injection pipe column is damaged is solved.

Description

Technical Field

[0001] The utility model relates to the field of utilizing thermal energy to extract oil from a well, in particular to a gas injection balancing valve and a gas injection pipe column. Background Art

[0002] In the prior art, when oil is produced, a large amount of water will remain in the annulus between the oil pipe and the casing above the packer due to sand flushing and other reasons. And this water cannot be easily discharged. When thermal oil is produced through the oil pipe, it is generally necessary to inject gas into the well through the oil pipe. Since the water vapor injected through the oil pipe is high-temperature and high-pressure, when these vapors move toward the oil layer in the oil pipe, the water in the annulus will turn into water vapor. And the water vapor cannot easily leave the annulus, which will cause the pressure in the annulus to increase. When there is a large amount of water in the annulus, the casing will be blocked by high pressure, causing a safety hazard. If the pressure is too high, it may even cause casing damage. Utility Model Content

[0003] The utility model aims to provide a gas injection balancing valve to solve the problem in the prior art that water in the casing annulus evaporates due to heat during gas injection, causing excessive pressure in the casing annulus and thus damaging the casing. The utility model also provides a gas injection string to solve the problem in the prior art that water in the casing annulus evaporates due to heat during gas injection, causing excessive pressure in the casing annulus and thus damaging the gas injection string.

[0004] A gas injection balancing valve comprises an outer shell for being connected in series to a pipe column, an inner shell being provided with an upper and lower through-going gas injection channel, an inner shell being provided with a valve body assembly, the inner shell being provided with an air inlet channel having one end connected to the gas injection channel and the other end connected to the casing annulus outside the outer shell, a one-way valve being connected in series to the air inlet channel for allowing high-pressure steam in the casing annulus to enter and flow to the gas injection channel when the pressure in the casing annulus reaches a set pressure.

[0005] Furthermore, the valve body assembly includes a fixed cavity located in the middle position of the outer shell, one end of the fixed cavity is open, the air injection channel is located between the fixed cavity and the outer shell, the air inlet channel includes a radial extension section that extends radially to pass through the outer shell and connect to the fixed cavity, and the one-way valve is installed in the fixed cavity and the valve port is connected to the fixed cavity.

[0006] Furthermore, the shell has a solid section in the middle, a blind hole is opened in the center of the solid section, the inner cavity of the blind hole constitutes a fixed cavity, and the gas injection channel includes a plurality of circumferential through holes opened on the solid section and arranged around the fixed cavity.

[0007] Furthermore, the opening of the blind hole faces the gas injection direction, and the radial extension section is located at the bottom of the blind hole.

[0008] Furthermore, the one-way valve is a two-stage one-way valve.

[0009] The utility model provides a new gas injection balancing valve. Specifically: the utility model connects the annulus with the gas injection channel by setting an air inlet channel, and then closes the air inlet channel through a one-way valve. During normal gas injection, the one-way valve is closed, and the injected steam will not escape into the casing annulus through the air inlet channel. When the water in the casing annulus is heated and evaporated, causing the pressure in the casing annulus to be greater than or equal to the set pressure, the one-way valve will be opened, and the steam in the annulus enters the gas injection channel and then follows the steam in the injection well into the oil layer, and the pressure in the casing annulus is released. When the pressure in the casing annulus is reduced, the one-way valve is closed. In summary, the solution provided by the utility model solves the problem in the prior art that the water in the annulus is heated and evaporated during gas injection, causing the pressure in the annulus to be too high and thus damaging the casing.

[0010] At the same time, the water vapor in the annulus follows the injected steam into the oil layer for oil production, making use of the water in the annulus. And because the steam in the annulus must reach a certain pressure before the one-way valve can be opened, it also ensures that the temperature of the steam injected into the oil layer will not change too much, thereby ensuring the quality of the steam during oil production.

[0011] A gas injection pipe column comprises an oil pipe, on which a gas injection balancing valve is connected in series. The gas injection balancing valve comprises an outer shell, in which an injection channel which passes through the outer shell from top to bottom is provided, and in which a valve body assembly is also provided. The valve body assembly has an air inlet channel which is connected to the air injection channel at one end and to the casing annulus outside the outer shell at the other end. A one-way valve is connected in series to the air inlet channel, for allowing high-pressure steam in the casing annulus to enter and flow to the gas injection channel when the pressure in the casing annulus reaches a set pressure.

[0012] Furthermore, the valve body assembly includes a fixed cavity in the middle of the outer shell, one end of the fixed cavity is open, the air injection channel is between the fixed cavity and the outer shell, the air inlet channel includes a radial extension section that extends radially to pass through the outer shell and connect to the fixed cavity, and the one-way valve is installed in the fixed cavity and the valve port is connected to the fixed cavity.

[0013] Furthermore, the shell has a solid section in the middle, a blind hole is opened in the center of the solid section, the inner cavity of the blind hole constitutes a fixed cavity, and the gas injection channel includes a plurality of circumferential through holes opened on the solid section and arranged around the fixed cavity.

[0014] Furthermore, the opening of the blind hole faces the gas injection direction, and the radial extension section is located at the bottom of the blind hole.

[0015] Furthermore, the one-way valve is a two-stage one-way valve.

[0016] The utility model improves the prior art. Specifically, the utility model is provided with a gas injection balance valve, and the casing annulus is connected with the gas injection channel by providing an air inlet channel, and then the air inlet channel is closed by a one-way valve. During normal gas injection, the one-way valve is closed, and the injected steam will not escape into the casing annulus through the air inlet channel. When the water in the casing annulus is heated and evaporated, causing the pressure in the casing annulus to be greater than or equal to the set pressure, the one-way valve will be opened, and the steam in the annulus enters the gas injection channel and then enters the oil layer together with the steam in the injection well, and the pressure in the casing annulus is released. When the pressure in the casing annulus is reduced, the one-way valve is closed. In summary, the solution provided by the utility model solves the problem in the prior art that the water in the casing annulus is heated and evaporated during gas injection, causing the pressure in the casing annulus to be too high, thereby causing damage to the gas injection pipe column.

[0017] At the same time, the water vapor in the annulus follows the injected steam into the oil layer for oil production, making use of the water in the annulus. And because the steam in the annulus must reach a certain pressure before the one-way valve can be opened, it also ensures that the temperature of the steam injected into the oil layer will not change too much, thereby ensuring the quality of the steam during oil production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 : A structural schematic diagram of a gas injection balancing valve of an embodiment of a gas injection pipe column of the utility model;

[0019] Figure 2 AA cross-sectional view of the gas injection balancing valve of the gas injection pipe column embodiment of the utility model;

[0020] Figure 3 : A front view of a gas injection balancing valve of a gas injection pipe column according to an embodiment of the utility model.

[0021] In the figure: 1. outer shell; 2. valve body assembly; 3. one-way valve; 4. air injection channel; 5. air inlet channel; 6. fixed cavity; 7. solid section; 8. blind hole; 9. first ball valve; 10. first valve ball; 11. first ball valve seat; 12. second ball valve; 13. second valve ball; 14. second ball valve seat; 15. first compression spring; 16. second compression spring; 17. connecting pipe; 18. cover. DETAILED DESCRIPTION

[0022] The specific concept of the gas injection string of the utility model is as follows:

[0023] A gas injection pipe column includes an oil pipe with a gas injection balance valve in series on the oil pipe. The gas injection balance valve includes an outer shell, an upper and lower gas injection channel is provided in the outer shell, and a valve body assembly is also provided in the outer shell. The valve body assembly has an air inlet channel connected to the air injection channel at one end and connected to the casing annulus outside the outer shell at the other end. A one-way valve is connected in series on the air inlet channel for allowing high-pressure steam in the casing annulus to enter and flow to the gas injection channel when the pressure in the casing annulus reaches a set pressure.

[0024] The utility model has an air injection balance valve connected in series between two sections of oil pipes. The air injection balance valve is located on the liquid surface of the packer and the casing annulus on the packer. An air injection channel and an air inlet channel connecting the casing annulus with the air injection balance valve are arranged in the air injection balance valve, and a one-way valve closes the air injection channel and the air inlet channel, so that the steam entering the oil layer through the air injection channel will not easily enter the air inlet channel. When the water in the casing annulus is heated and evaporated, the pressure in the casing annulus increases. When the pressure increases to a certain degree, the one-way valve is opened, and the water vapor in the casing annulus enters the air injection channel and follows the steam of oil production into the oil layer. It not only prevents the pressure in the casing annulus from being too high, resulting in casing damage, but also reuses the steam in the casing annulus to avoid heat waste.

[0025] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0026] Embodiment 1 of the gas injection column of the utility model:

[0027] like Figure 1-3 As shown: a gas injection string, including an oil pipe, on which a gas injection balancing valve is connected in series, the gas injection balancing valve includes an outer shell 1, in which an injection channel 4 is provided which runs through the outer shell 1 from top to bottom, and in which a valve body assembly 2 is also provided, the valve body assembly 2 has an end which is connected to the gas injection channel 4, and an inlet channel 5 which is connected to the casing annulus outside the outer shell 1 at the other end, and a one-way valve 3 is connected in series to the inlet channel 5 for allowing high-pressure steam in the casing annulus to enter and flow to the gas injection channel 4 when the pressure in the casing annulus reaches a set pressure.

[0028] Generally speaking, as long as the gas inlet channel 5 is opened on the gas injection balance valve and the casing annulus is connected to the gas injection channel 4, the steam in the casing annulus can enter the gas injection channel 4, and the one-way valve 3 is set to prevent the steam in the gas injection channel 4 from entering the casing annulus, the purpose of releasing the pressure in the casing can be achieved. However, in order to ensure the quality of the steam in the gas injection channel 4, the one-way valve 3 needs to be opened only after the steam in the casing annulus reaches a certain pressure, and the steam in the casing annulus can enter the gas injection channel 4.

[0029] Further optimized, the valve body assembly 2 includes a fixed cavity 6 in the middle of the shell 1, one end of the fixed cavity 6 is open, the gas injection channel 4 is between the fixed cavity 6 and the shell 1, the air inlet channel 5 includes a radial extension section extending radially to penetrate the shell 1 and communicate with the fixed cavity 6, and the one-way valve 3 is installed in the fixed cavity 6 and the valve port is communicated with the fixed cavity 6. The fixed cavity 6 makes the installation of the one-way valve 3 more convenient and easier.

[0030] There are many ways to form the fixed cavity 6. For example, a corresponding tubular structure can be fixedly installed in the oil pipe, with one end of the tubular structure closed and the other end open. A corresponding connecting pipe is also provided on the side wall of the tubular structure, one end of the connecting pipe extends out of the shell 1, and the other end is connected to the inside of the tubular structure to form an air intake channel 5, and the gap between the side wall of the tubular structure and the shell forms an injection channel 4. However, in this way, the position where the tubular structure is fixed to the shell 1 requires sufficient strength, otherwise the tubular structure may be detached under the impact of steam in the injection well. And during installation, the installation difficulty is relatively large. Therefore, preferably: the middle part of the shell 1 has a solid section 7, the center of the solid section 7 is provided with a blind hole 8, the inner cavity of the blind hole 8 constitutes the fixed cavity 6, the one-way valve 3 is installed in the blind hole 8, and the air intake channel 5 is connected to the blind hole 8. The injection channel 4 includes a plurality of circumferential through holes arranged around the fixed cavity 6 on the solid section 7. The solid section 7 is integrally arranged with the shell 1, and the problem of failure of the injection balance valve will not occur under the impact of steam.

[0031] The direction of the opening of the blind hole 8 is the direction in which the steam in the annulus enters the gas injection channel 4. Generally speaking, there are two opening directions of the blind hole 8, one is opposite to the gas injection direction, and the other is the same as the gas injection direction. Preferably: the opening direction of the blind hole 8 is opposite to the gas injection direction, and the radial extension section is at the bottom of the blind hole 8. If the opening direction of the blind hole 8 is the same as the gas injection direction, the steam in the casing annulus only needs to open the one-way valve 3 to enter the gas injection channel 4 and then enter the oil layer. If the opening direction of the blind hole 8 is opposite to the gas injection direction, the steam in the casing annulus not only needs to open the one-way valve 3, but also needs to resist the force exerted by the steam in the gas injection channel 4 on the one-way valve 3. Only when the steam in the casing annulus overcomes the force of the steam in the gas injection channel 4 can it enter the gas injection channel 4 and then enter the oil layer. This requires that the steam in the casing annulus has a sufficiently large pressure, thereby ensuring the quality of the steam in the casing annulus when entering the gas injection channel 4, and preventing unqualified steam from entering the oil layer and affecting oil production.

[0032] If the one-way valve 3 is a one-stage one-way valve 3, its sealing effect is relatively not very good, and it is not possible to isolate the oil pipe and the casing well. Therefore, preferably: the one-way valve 3 is a two-stage one-way valve 3. With the two-stage one-way valve 3, the steam in the casing annulus opens the first stage of the one-way valve 3, enters the one-way valve 3, and then opens the second stage of the one-way valve 3 to enter the gas injection channel 4. The two-stage one-way valve 3 is sealed and isolated from the oil pipe and the casing, so that the steam in the casing annulus will not easily enter the gas injection channel 4 directly.

[0033] The one-way valve 3 in this embodiment is a combination of two ball valves, and in order to ensure that the one-way valve 3 can be opened only under a specific pressure, a corresponding compression spring fixed on the valve ball of the ball valve is also provided. Of course, in other embodiments, two overflow valves can also be combined into one one-way valve 3.

[0034] The first ball valve 9 is fixed at the bottom of the blind hole 8, the first ball valve seat 11 is connected to the air inlet channel 5, the first valve ball 10 cooperates with the side of the first ball valve seat 11 facing away from the gas injection direction, and the first compression spring 15 is also fixed on the first valve ball 10, and the first compression spring 15 presses the first valve ball 10 against the first ball valve seat 11. The second ball valve 12 is fixed at the end of the fixed cavity 6, the second ball valve seat 14 is fixed at the end of the fixed cavity 6, and the second valve ball 13 cooperates with the side of the second ball valve seat 14 facing away from the first ball valve 9. The second ball valve seat 14 is connected to a connecting pipe 17 on the side facing the first ball valve 9, and a step structure is provided on the outer wall of the connecting pipe 17. One end of the first compression spring 15 is fixed on the first valve ball 10, and the other end abuts on the step structure. The end of the blind hole 8 is covered with a cover 18, and a compression spring bracket is provided in the cover 18, and the second compression spring 16 is sleeved on the compression spring bracket. In order to ensure the sealing performance, the first ball valve seat 11 and the second ball valve seat 14 are both sealed and installed in the blind hole 8 through sealing rings, and the surfaces of the first valve ball 10 and the second valve ball 13 are processed to achieve complete sealing with the first ball valve seat 11 and the second ball valve seat 14.

[0035] When the utility model is used, the water in the casing annulus is heated and evaporated, and the steam in the casing annulus enters the blind hole 8 along the air inlet channel 5 at the bottom of the balance valve, and opens the first ball valve 9, and then the steam in the casing annulus opens the second ball valve 12. The steam in the casing annulus enters the gas injection channel 4 and then enters the oil layer.

[0036] The specific structure of the embodiment of the gas injection balance valve of the utility model is the same as the structure of the gas injection balance valve in the gas injection pipe column mentioned above, and will not be repeated in this article. In addition, during the oil production process after gas injection, the casing can be pressurized, and the utility model can be used to backwash the well and add thin oil to extend the production time of the oil well.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the description and drawings of the present invention shall be included in the protection scope of the present invention.

Claims

1. A gas injection balancing valve, characterized in that: It includes an outer shell for being connected in series to a pipe column, wherein an injection passage which passes through the outer shell from top to bottom is provided in the outer shell, and a valve body assembly is also provided in the outer shell, wherein the valve body assembly has an air inlet passage which is connected to the injection passage at one end and to the casing annulus outside the outer shell at the other end, and a one-way valve is connected in series to the air inlet passage for allowing high-pressure steam in the casing annulus to enter and flow to the injection passage when the pressure in the casing annulus reaches a set pressure.

2. The gas injection balancing valve according to claim 1, characterized in that: The valve body assembly includes a fixed cavity located in the middle of the shell, one end of the fixed cavity is open, the air injection channel is located between the fixed cavity and the shell, the air inlet channel includes a radial extension section that extends radially to pass through the shell and connect to the fixed cavity, and the one-way valve is installed in the fixed cavity and the valve port is connected to the fixed cavity.

3. The gas injection balancing valve according to claim 2, characterized in that: The middle part of the shell has a solid section, the center of the solid section is provided with a blind hole, the inner cavity of the blind hole constitutes a fixed cavity, and the gas injection channel includes a plurality of circumferential through holes arranged on the solid section and surrounding the fixed cavity.

4. The gas injection balancing valve according to claim 3, characterized in that: The opening of the blind hole faces the gas injection direction, and the radial extension section is located at the bottom of the blind hole.

5. The gas injection balancing valve according to any one of claims 1 to 4, characterized in that: The one-way valve is a two-stage one-way valve.

6. A gas injection string, comprising an oil pipe, characterized in that: An injection balancing valve is connected in series to the oil pipe, and the injection balancing valve includes an outer shell, an injection channel which runs through the outer shell from top to bottom, and a valve body assembly which is provided in the outer shell. The valve body assembly has an air inlet channel which is connected to the air injection channel at one end and connected to the casing annulus outside the outer shell at the other end. A one-way valve is connected in series to the air inlet channel for allowing high-pressure steam in the casing annulus to enter and flow to the air injection channel when the pressure in the casing annulus reaches a set pressure.

7. The gas injection string according to claim 6, characterized in that: The valve body assembly includes a fixed cavity located in the inner middle position, one end of the fixed cavity is open, the air injection channel is located between the fixed cavity and the outer shell, the air inlet channel includes a radial extension section that extends radially to pass through the outer shell and connect to the fixed cavity, and the one-way valve is installed in the fixed cavity and the valve port is connected to the fixed cavity.

8. The gas injection string according to claim 7, characterized in that: The middle part of the shell has a solid section, the center of the solid section is provided with a blind hole, the inner cavity of the blind hole constitutes a fixed cavity, and the gas injection channel includes a plurality of circumferential through holes arranged on the solid section and surrounding the fixed cavity.

9. The gas injection string according to claim 8, characterized in that: The opening of the blind hole faces the gas injection direction, and the radial extension section is located at the bottom of the blind hole.

10. The gas injection string according to any one of claims 6 to 9, characterized in that: The one-way valve is a two-stage one-way valve.

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