Gas recovery well drainage device and method in recovery process of water-containing gas reservoir well

Abstract

The invention provides a drainage device and method for a gas recovery well in the recovery process of a water-containing gas reservoir well. The drainage device comprises a first channel, a second channel and a drainage device, the second channel is used for injecting gas; wherein the first channel is an inner cavity of the oil pipe; the second channel is an inner cavity of the oil-string casing; the first channel and the second channel are communicated and connected; two circulation channels are established on the basis of an original gas production pipe column, a gas lift circulation drainage channel is formed through combination, gas lift drainage of different scales of drainage amounts is achieved according to different working conditions, the well drainage effect is improved, and particularly the technical problem of large-displacement drainage of a horizontal well is economically solved by converting a horizontal gas production well into a drainage well.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to a gas production well drainage device and method during the production process of a gas reservoir well with water. Background Art

[0002] During the development of a gas reservoir, as the balance of the internal pressure system is broken, water from the edges and bottom invades in the direction of the fastest pressure drop and flows toward the gas wells. Affected by the gravity of the liquid phase fluid and flow slippage, it is easy to cause liquid accumulation in the wellbore and shutdown of production. Therefore, it is necessary to discharge the accumulated liquid in the gas wellbore.

[0003] Among the existing technologies, foam drainage, gas lift drainage and electric pump drainage are relatively mature drainage technologies. Foam drainage is suitable for the early stage of water breakthrough in production wells and the well conditions with small water production. Electric pump drainage requires the electric pump to be lowered into the wellbore, which has high operating costs. At the same time, in order to avoid burning the pump, the gas production volume must be small, which limits its use. Gas lift drainage has the most extensive requirements on well conditions, and the best application effect is the drainage string with multi-stage gas lift valves. However, it is required to consider the later drainage needs and lower the multi-stage gas lift valve string in advance before the well is completed and put into production.

[0004] However, in the actual development process, water invasion of gas fields is more complicated, and some gas wells see water or see water early when they are put into production. It is necessary to optimize the well network and convert some gas wells into drainage wells for development. In particular, gas fields are mainly developed with horizontal wells. It is difficult to convert horizontal wells into drainage wells, and the drainage volume is low, which cannot meet the geological drainage needs. Specifically, it is difficult for foam and electric pumps to penetrate into the horizontal section to play a drainage role, and the drainage operation of replacing the multi-stage gas lift valve string in the horizontal well is complicated and the operation cost is high. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a gas well drainage device and method during the production process of a gas reservoir with water, which can more economically solve the technical problem of large-volume drainage of horizontal wells. Field tests can meet the development needs of converting gas wells into drainage wells after water is seen.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The present invention provides a gas well drainage device during the production process of a gas reservoir well with water, comprising:

[0008] a first passage for producing fluid;

[0009] a second channel for gas injection;

[0010] Wherein, the first channel is the inner cavity of the oil pipe; the second channel is the inner cavity of the oil layer casing;

[0011] The first channel and the second channel are interconnected.

[0012] Preferably, the inlet of the second channel is connected to an external gas injection device.

[0013] Preferably, an opening is provided on the side wall of the first channel, and the first channel is interconnected with the second channel through the opening.

[0014] Preferably, a plurality of openings are provided on the side wall of the first channel, and the first channel is interconnected with the second channel through the openings;

[0015] The plurality of openings are evenly distributed along the circumferential direction of the first channel.

[0016] Preferably, a divider is provided between the first channel and the second channel, and the divider is placed below the opening.

[0017] Preferably, it further comprises a third channel for gas injection, wherein the third channel is an inner cavity of a pipe column disposed in the first channel.

[0018] Preferably, the air inlet of the third channel is connected to an external gas injection device.

[0019] Preferably, the outlet of the third passage is disposed in the inner cavity of the production layer casing.

[0020] A method for draining a gas well during the production process of a gas reservoir well containing water comprises the following steps:

[0021] Determine the amount of water in the gas well;

[0022] Select the corresponding drainage device according to the determined water volume.

[0023] Preferably, a corresponding drainage device is selected according to the determined water volume, and the specific method is:

[0024] When the formation fluid in the gas production well is a gas-liquid mixed phase, the selected drainage device includes a first channel for producing fluid;

[0025] a second channel for gas injection;

[0026] Wherein, the first channel is the inner cavity of the oil pipe; the second channel is the inner cavity of the oil layer casing;

[0027] The first channel and the second channel are interconnected;

[0028] When the formation fluid in the gas production well is in liquid phase, the selected drainage device includes a first channel for producing fluid;

[0029] a second channel for gas injection;

[0030] Wherein, the first channel is the inner cavity of the oil pipe; the second channel is the inner cavity of the oil layer casing;

[0031] The first channel and the second channel are interconnected;

[0032] The invention also comprises a third channel for gas injection, wherein the third channel is an inner cavity of a pipe column disposed in the first channel.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention provides a gas well drainage device for use in the production process of a well with water in a gas reservoir. Two flow channels are established on the basis of an original gas production pipe column. A gas lift circulation drainage channel is formed by combination. Gas lift drainage of different scales of drainage is achieved according to different working conditions, thereby improving the well drainage effect, especially for converting a horizontal gas well into a drainage well. The technical problem of large-volume drainage of a horizontal well is solved more economically.

[0035] Furthermore, a third channel is set up to supplement the circulating gas injection through the second channel and the third channel, increase the ground pressurized gas lifting driving energy at different depths, improve the liquid phase production capacity of the pipe string, and meet the geological needs of large-volume drainage. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Gas well production string;

[0037] Figure 2 Gas well transfer drainage pipe string 1;

[0038] Figure 3 Gas well transfer drainage pipe string 2;

[0039] Among them, 1-oil layer casing; 2-production oil pipe; 3-separator; 4-production layer casing; 5-pressure gauge; 6-opening; 7-tubing string; V1-first channel; V2-second channel; V3-third channel; T1-first wellhead; T2-second wellhead; T3-third wellhead. DETAILED DESCRIPTION

[0040] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0041] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0042] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0043] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0044] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0045] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0046] In the actual gas field development process, it is necessary to optimize and adjust the well network to convert some gas production wells into drainage wells for efficient development. The content of the present invention will be described in detail below in conjunction with the accompanying drawings so that those skilled in the art can understand the content of the present invention in more detail.

[0047] Figure 1 It is a schematic diagram of an existing gas well production string, wherein the gas production device of the gas well includes a production layer casing 4, the outlet of the production layer casing 4 is connected to an oil layer casing 1, an oil pipe 2 is arranged in the inner cavity of the oil layer casing 1, and the gas outlet of the oil pipe 2 is connected to ground equipment.

[0048] The air inlet of the oil pipe 2 is placed at the air inlet of the oil pipe 2 .

[0049] A separator 3 is provided between the air inlet of the oil pipe 2 and the oil layer casing 1 .

[0050] A separator 3 is provided at the outlet of the oil layer casing 1 .

[0051] During the gas production process of the gas well, the formation fluid is mainly in the gas phase. The fluid enters the first channel V1 through the production layer casing 4, reaches the surface equipment through the first wellhead T1, and the formation fluid is produced.

[0052] At this time, the specific gravity of the formation fluid is small, and the energy mode for fluid extraction is mainly driven by the natural high pressure of the formation.

[0053] Example 1

[0054] Figure 2 A schematic diagram of a gas well drainage column provided in the present application. A gas well drainage device during the production process of a gas reservoir with water provided in the present embodiment comprises a production layer casing 4, the outlet of the production layer casing 4 is connected to an oil layer casing 1, an oil pipe 2 is arranged in the inner cavity of the oil layer casing 1, and the gas outlet of the oil pipe 2 is connected to ground equipment.

[0055] A separator 3 is provided between the air inlet of the oil pipe 2 and the oil layer casing 1 .

[0056] The outlet of the oil layer casing 1 serves as a second wellhead T2 for gas injection into the drainage well, and the gas inlet of the second wellhead T2 is connected to the gas injection equipment on the ground.

[0057] The inner cavity of the oil layer casing 1 serves as a second channel V2 of the drainage well, and the second channel V2 is connected to the second wellhead T2.

[0058] The inner cavity of the oil pipe 2 serves as the first channel V1 of the drainage well, and the outlet of the oil pipe 2 serves as the first wellhead T1 of the water outlet of the drainage well.

[0059] The side wall of the oil pipe 2 is provided with an opening 6 .

[0060] The opening 6 is provided with one.

[0061] There are a plurality of openings 6 , and the plurality of openings 6 are evenly distributed along the circumferential direction of the oil pipe 2 .

[0062] The second channel V2 is connected to the first channel V1 through the opening 6 .

[0063] Working process:

[0064] After water invasion of the gas reservoir, water is seen in the gas production wells. The well pattern is adjusted to convert the gas production wells into drainage wells. The formation fluid is mainly a mixed phase of gas and liquid. The fluid enters the first channel V1 through the production layer casing 4, reaches the surface equipment through the first wellhead T1, and the formation fluid is produced.

[0065] At this time, the fluid specific gravity increases and the flow resistance is large. In order to achieve the drainage effect, the ground equipment pressurizes and injects additional gas, which enters the second channel V2 through the second wellhead T2 and enters the first channel V1 from the opening 6 to be produced together with the formation fluid.

[0066] It should be noted that the injected gas is nitrogen or a gas similar to the formation fluid.

[0067] The energy mode of fluid extraction is mainly driven by natural energy and natural high-pressure energy in the formation, and mainly driven by natural high-pressure energy in the formation and ground pressurized gas lift in the wellbore.

[0068] Example 2

[0069] Figure 3 Schematic diagram of a gas well drainage column 2. This embodiment provides a gas well drainage device during the production process of a gas reservoir with water, comprising a production layer casing 4, the outlet of the production layer casing 4 is connected to an oil layer casing 1, an oil pipe 2 is arranged in the inner cavity of the oil layer casing 1, and the gas outlet of the oil pipe 2 is connected to ground equipment.

[0070] A separator 3 is provided between the air inlet of the oil pipe 2 and the oil layer casing 1 .

[0071] A tubing string 7 is arranged in the inner cavity of the oil pipe 2 , and a gas outlet of the tubing string 7 is disposed in the inner cavity of the production layer casing 4 .

[0072] The air inlet of the pipe string 7 serves as the third wellhead T3, and the air inlet of the third wellhead T3 is connected to the gas injection equipment on the ground.

[0073] The inner cavity of the pipe column 7 serves as the third channel V3 of the drainage well.

[0074] The outlet of the oil layer casing 1 serves as a second wellhead T2 for gas injection into the drainage well, and the gas inlet of the second wellhead T2 is connected to the gas injection equipment on the ground.

[0075] The inner cavity of the oil layer casing 1 serves as a second channel V2 of the drainage well, and the second channel V2 is connected to the second wellhead T2.

[0076] The inner cavity of the oil pipe 2 serves as the first channel V1 of the drainage well, and the outlet of the oil pipe 2 serves as the first wellhead T1 of the water outlet of the drainage well.

[0077] The side wall of the oil pipe 2 is provided with an opening 6 .

[0078] The opening 6 is provided with one.

[0079] There are a plurality of openings 6 , and the plurality of openings 6 are evenly distributed along the circumferential direction of the oil pipe 2 .

[0080] The second channel V2 is connected to the first channel V1 through the opening 6 .

[0081] Working process:

[0082] After further water invasion of the gas reservoir, the well pattern is adjusted to convert the gas production well into a drainage well, which requires further large-volume drainage. The formation fluid is mainly liquid phase. The fluid enters the first channel V1 through the production layer casing 4, passes through the first wellhead T1 to reach the surface equipment, and the formation fluid is produced.

[0083] At this time, the formation fluid has a high specific gravity and the natural flow resistance of the wellbore is large. In order to achieve the drainage effect, ground equipment is required to increase the pressure and inject additional gas, which enters the second channel V2 through the second wellhead T2 and enters the first channel V1 from the opening 6 to be extracted together with the formation fluid.

[0084] At the same time, additional gas is injected by combining ground equipment, enters the third channel V3 through the third wellhead T3, enters the first channel V1 from the pipe string 7 and the annulus of the production oil pipe, and is produced together with the formation fluid.

[0085] At this time, the injected gas is nitrogen or a gas similar to the formation fluid.

[0086] The main energy modes for fluid extraction are natural high-pressure driving of the formation and lifting driving of surface pressurized gas.

[0087] It should be noted that by supplementing the circulating gas injection through the second channel V2 and the third channel V3, the surface pressurized gas lifting driving energy is increased at different depths, the liquid phase production capacity of the pipe string is improved, and the geological needs of large-volume drainage are met.

[0088] It should be noted that the gas lift position of the second channel V2 is far from the production layer, and the lifting depth is shallow. It can improve the drainage capacity of the pipe string above the opening 6 position, but cannot further improve the drainage capacity of the pipe string near the production layer. The gas lift position of the third channel V3 is close to the production layer, which can improve the drainage capacity of the pipe string near the production layer. However, if the gas lift volume is too large, the overburden pressure near the production layer will be increased, and the formation fluid will be inhibited from entering the production layer casing 4. Therefore, it is necessary to combine the second channel V2 and the third channel V3, and configure the appropriate gas lift volume of each through double circulation to improve the drainage capacity.

[0089] Example 3

[0090] This embodiment provides a method for dewatering a gas well during the production process of a gas reservoir with water, comprising the following steps:

[0091] Determine the amount of water in the gas well;

[0092] A corresponding drainage device is selected according to the determined water volume. When the formation fluid in the gas well is a gas-liquid mixed phase, the drainage device described in Example 1 is selected for drainage; when the formation fluid in the gas well is a liquid phase, the drainage device described in Example 2 is selected for drainage.

[0093] It should be noted that the above-mentioned gas wells include vertical wells, inclined wells, and horizontal wells, among which the drainage conversion of horizontal wells is the most complicated. The above-mentioned embodiment uses the drainage conversion of horizontal wells for graphic description. The above content is applicable to other types of gas wells, and will not be explained one by one here.

[0094] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A gas well drainage device during the production process of a gas reservoir with water, characterized in that: include: a first passage for producing fluid; a second channel for gas injection; Wherein, the first channel is the inner cavity of the oil pipe (2); The second channel is the inner cavity of the oil layer casing (1); The first channel and the second channel are interconnected.

2. The gas well drainage device in the production process of a water-containing gas reservoir according to claim 1, characterized in that: The inlet of the second channel is connected to an external gas injection device.

3. The gas well drainage device in the production process of a water-containing gas reservoir according to claim 1, characterized in that: An opening (6) is provided on the side wall of the first channel, and the first channel is interconnected with the second channel through the opening (6).

4. The gas well drainage device in the production process of a gas reservoir with water according to claim 1, characterized in that: A plurality of openings (6) are provided on the side wall of the first channel, and the first channel is interconnected with the second channel through the openings (6); The plurality of openings (6) are evenly distributed along the circumferential direction of the first channel.

5. A gas well drainage device for gas production during the production process of a gas reservoir with water according to claim 3 or 4, characterized in that: A divider (3) is also provided between the first channel and the second channel, and the divider (3) is placed below the opening (6).

6. The gas well drainage device in the production process of a water-containing gas reservoir according to claim 1, characterized in that: It also comprises a third channel for gas injection, wherein the third channel is the inner cavity of a pipe column (7) disposed in the first channel.

7. The gas well drainage device in the production process of a gas reservoir with water according to claim 6, characterized in that: The air inlet of the third channel is connected to an external air injection device.

8. The gas well drainage device in the process of producing gas from a water-bearing gas reservoir according to claim 6, characterized in that: The outlet of the third channel is placed in the inner cavity of the production layer casing (4).

9. A method for dewatering a gas well during the production process of a gas reservoir with water, characterized in that: The following steps are involved: Determine the amount of water in the gas well; Select the corresponding drainage device according to the determined water volume.

10. A method for dewatering a gas well during production of a gas reservoir with water according to claim 9, characterized in that: Select the corresponding drainage device according to the determined water volume. The specific method is: When the formation fluid in the gas production well is a gas-liquid mixed phase, the selected drainage device includes a first channel for producing fluid; a second channel for gas injection; Wherein, the first channel is the inner cavity of the oil pipe (2); the second channel is the inner cavity of the oil layer casing (1); The first channel and the second channel are interconnected; When the formation fluid in the gas production well is in liquid phase, the selected drainage device includes a first channel for producing fluid; a second channel for gas injection; Wherein, the first channel is the inner cavity of the oil pipe (2); the second channel is the inner cavity of the oil layer casing (1); The first channel and the second channel are interconnected; It also comprises a third channel for gas injection, wherein the third channel is the inner cavity of a pipe column (7) disposed in the first channel.

Images