Separate injection tubular column of polymer injection well

Abstract

The utility model relates to the technical field of oil production engineering, in particular to a polymer injection well separate injection tubular column. The polymer injection well separate injection pipe column comprises a double-layer pipe section, an upper single-layer pipe section and a lower single-layer pipe section, the double-layer pipe section comprises an outer pipe section and an inner pipe section, the outer pipe section is provided with an upper communication structure and a lower communication structure, and the lower single-layer pipe section is further provided with a bottom communication structure connected to the second annulus. The upper single-layer pipe section, the lower single-layer pipe section and the inner pipe section form an independent channel, another independent channel, namely the first annular space, is formed between the outer pipe section and the inner pipe section, the first annular space can directly cross an upper oil layer to enter the lower oil layer for liquid injection, and liquid does not need to be injected into the upper oil layer. Therefore, the problem that the polymer cannot be used when the uppermost oil layer does not need to be injected and the lower oil layer needs to be injected due to the fact that the polymer must pass through the uppermost oil layer when the polymer is directly injected in the space between the sleeve and the pipe column in the prior art is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of oil production engineering, in particular to a polymer injection well injection string. Background Art

[0002] The pressure inside the oil layer is relatively high. During the oil field exploitation process, the oil will be squeezed upward along the oil pipe under the pressure inside the oil layer, which makes it easier to exploit the oil. As the oil in the oil layer is lost, the pressure of the oil layer decreases. Therefore, during the exploitation process, it is necessary to inject supplementary fluid into the oil layer to ensure the pressure inside the oil layer. Usually, operators will lower a water injection string into the injection well to inject water into the oil layer to supplement the pressure. In addition, there are often multiple oil layers distributed in the same injection well, and the oil layers are distributed up and down. During the water injection process, each oil layer needs to be operated separately.

[0003] For example, a Chinese invention patent application with an application publication date of February 12, 2019 and application publication number CN109322648A discloses a distribution injection string for oil well water injection and a method of use, the distribution injection string includes a first outer tube and a first inner tube, the bottom of the first outer tube is also connected in sequence with a third outer tube, a first dispenser and a fourth outer tube, the first inner tube extends between the first dispenser and the fourth outer tube, a screen tube is also provided at the bottom of the fourth outer tube, during water injection, the space inside the first inner tube and between the first outer tube and the first inner tube are independent of each other. The first inner tube is directly connected to the screen tube, and water is injected into the oil layer where the screen tube is located; the space between the first inner tube and the first outer tube is connected to the first dispenser, and water is injected into the oil layer where the first dispenser is located.

[0004] In the prior art, in order to increase the displacement volume and increase the displacement efficiency in the later stage of water injection, a relatively viscous polymer is also injected. Since the above-mentioned injection string needs to inject water between multiple oil layers, the string is often offset and the diameter of each string is small, especially the diameter of the inner tube is narrower. When the polymer is injected, the polymer will block the injection pipe. Therefore, in the injection of polymer, there is also a scheme of using the oil pipe and the annulus between the oil pipe and the casing for injection. Specifically, as Figure 1 As shown, during the polymer injection process, the upper packer 4 is first used to seal between the two oil layers to ensure that the upper oil layer 30 and the lower oil layer 50 are independent of each other, and then polymer is injected between the casing 13 and the oil pipe 17 and inside the oil pipe 17 respectively. The polymer between the casing 13 and the oil pipe 17 is injected into the upper oil layer 30, and the polymer inside the oil pipe 17 is injected into the lower oil layer 50.

[0005] However, in the actual geological environment, the oil layer does not only have two layers. The same oil and water well will pass through multiple oil layers. In the above technical solution, the annulus between the oil pipe and the casing is used for oil injection. Since the space between the oil pipe and the casing first passes through the topmost space, the injected polymer can only enter the topmost oil layer first. In other words, there are only two channels for polymer injection, and one of the channels must pass through the topmost oil layer. In the actual oil production process, it may happen that the topmost oil layer does not need to be injected with polymer, but the oil layer below needs to be injected with polymer. At this time, it is more difficult to inject the polymer. Utility Model Content

[0006] The utility model aims to provide a polymer injection well separation pipe string, which is used to solve the problem that when the polymer is directly injected into the space between the casing and the oil pipe in the prior art, the polymer must pass through the uppermost oil layer, resulting in the polymer being unable to be used when the uppermost oil layer does not need to be injected but the lower oil layer needs to be injected.

[0007] In order to achieve the above-mentioned purpose, the polymer injection well separation injection string in the utility model adopts the following technical scheme:

[0008] A distribution pipe string for a polymer injection well comprises a double-layer pipe section located in the middle of the distribution pipe string for the polymer injection well, an upper single-layer pipe section and a lower single-layer pipe section respectively located on the upper and lower sides of the double-layer pipe section, the double-layer pipe section comprises an outer pipe section and an inner pipe section connecting the upper single-layer pipe section and the lower single-layer pipe section, a first annulus is formed between the inner pipe section and the outer pipe section, the distribution pipe string for the polymer injection well is used to form a second annulus between the inner pipe section and the outer pipe section, an upper connecting structure and a lower connecting structure arranged at intervals for connecting to the first annulus and the second annulus are arranged on the outer pipe section, a packer for sealing the upper oil layer is also arranged between the two connecting structures on the outer pipe section, a bottom connecting structure connected to the second annulus is also arranged on the lower single-layer pipe section, a packer is arranged between the bottom connecting structure and the lower connecting structure to connect the lower connecting structure and the bottom connecting structure to different oil layers.

[0009] Furthermore, the polymer injection well injection string includes a double pipe joint, which includes a first connection structure arranged on the inner wall for connecting the internal pipe section, so as to divide the double pipe joint into an upper single-layer pipe section and an external pipe section along the first connection structure.

[0010] Furthermore, a first threaded section is also provided at the end of the double pipe joint located at the outer pipe section, and the outer pipe section includes a plurality of pipe sections.

[0011] Furthermore, the polymer injection well injection string includes an inserter, and a second connecting structure for connecting the internal pipe section is also provided on the inner wall of the inserter, so as to divide the inserter into a lower single-layer pipe section and an external pipe section along the second connecting structure.

[0012] Furthermore, the catheter introducer is provided with a second threaded section connected to the external pipe section, and the diameter of the second connecting structure is smaller than the diameter of the second threaded section.

[0013] Furthermore, the upper end of the external pipe segment is threadedly connected to the upper single-layer pipe segment or the internal pipe segment, and the lower end of the external pipe segment is threadedly connected to the lower single-layer pipe segment or the internal pipe segment, and the internal pipe segment includes a first plug-in segment and a second plug-in segment that are plugged into each other.

[0014] Furthermore, a sealing assembly is provided between the first plug-in section and the second plug-in section to ensure a sealed connection between the first plug-in section and the second plug-in section.

[0015] Furthermore, the first plug-in section is inserted inside the second plug-in section, a raised section is provided on the first plug-in section, at least one raised section is threadedly assembled on the surface of the first plug-in section, and the sealing component is arranged between two adjacent raised sections so that the sealing component can expand and deform outward under the extrusion of the raised section.

[0016] Furthermore, at least two groups of sealing components are provided, and the same convex section is provided between two adjacent sealing components so that the end surfaces at both ends of the convex section press the two adjacent sealing components respectively.

[0017] Furthermore, the upper connecting structure, the lower connecting structure and the bottom connecting structure are all sieve tubes.

[0018] The beneficial effects of the polymer injection well separation pipe string in the utility model are as follows: the utility model pioneers a polymer injection well separation pipe string, which is convenient for forming two liquid flow injection inlets by setting a double-layer pipe section. Since the double-layer pipe section includes an external pipe section and an internal pipe section, and the internal pipe section is connected to the upper single-layer pipe section and the lower single-layer pipe section, the upper single-layer pipe section, the lower single-layer pipe section and the internal pipe section form a separate channel, and another separate channel, namely the first annulus, is formed between the external pipe section and the internal pipe section. The first annulus is conveniently connected to the second annulus through the upper connecting structure and the lower connecting structure, and a packer for sealing the upper oil layer is also provided between the two connecting structures on the external pipe section, so as to facilitate the separation of the upper oil layer. The bottom connecting structure is provided so that the polymer injected from the upper single-layer pipe section can be injected into the lower oil layer through the bottom connecting structure and the packer, and due to the packer between the bottom connecting structure and the lower connecting structure, the bottom connecting structure and the lower connecting structure can flow through different oil layers respectively to supplement polymer to different oil layers, thereby solving the problem in the prior art that the polymer must pass through the uppermost oil layer when the space between the casing and the oil pipe is used to directly inject the polymer, resulting in the polymer being unable to be used when the uppermost oil layer does not need to be injected but the lower oil layer needs to be injected. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of polymer injection in the prior art;

[0020] Figure 2 It is a structural schematic diagram of an embodiment of a polymer injection well injection string in the utility model;

[0021] Figure 3 It is a structural schematic diagram of a double pipe joint of an embodiment of a polymer injection well separation injection pipe string in the utility model;

[0022] Figure 4 It is a structural schematic diagram of the first plug-in pipe section of an embodiment of the polymer injection well separation pipe string of the utility model;

[0023] Figure 5 It is a structural schematic diagram of the second insertion pipe section and the insertion device of the embodiment of the polymer injection well injection pipe string of the utility model.

[0024] In the figure: 1, upper single-layer pipe section; 2, double pipe joint; 3, upper connecting structure; 4, upper packer; 5, small oil pipe; 6, middle packer; 7, lower connecting structure; 8, first plug-in pipe section; 9, inserter; 10, lower packer; 11, bottom connecting structure; 12, plug; 13, casing; 14, second annulus; 15, first annulus; 16, lower single-layer pipe section; 17, oil pipe; 30, upper oil layer; 40, middle oil layer; 50 , lower oil layer; 21, third threaded section; 22, first connecting structure; 23, first threaded section; 81, first plug-in section body; 82, first sealing assembly; 83, first sealing ring; 84, first raised section; 85, second sealing assembly; 86, second sealing ring; 87, second raised section; 91, second plug-in section; 92, inserter body; 93, second threaded section; 94, second connecting structure; 95, fourth threaded section. DETAILED DESCRIPTION

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

[0026] The utility model forms two liquid flow channels in the oil pipe by arranging a double-layer pipe section on the oil pipe. The two liquid flow channels can respectively lead to different oil layers. The upper oil layer can be crossed by arranging the packer, so that the polymer can cross the upper oil layer and be directly injected into the lower oil layer.

[0027] In the embodiment 1 of the polymer injection well separation injection string (hereinafter referred to as the separation injection string) of the present utility model:

[0028] like Figure 2As shown, in this embodiment, the injection string is nested in the casing 13. As the casing 13 gradually extends downward, the injection string includes from top to bottom an upper single-layer pipe section 1 located at the top, a double-layer pipe section located in the middle, and a lower single-layer pipe section 16 located below the double-layer pipe section, wherein the double-layer pipe section includes an outer pipe section and an inner pipe section located on the outside, and the inner pipe section is located within the space surrounded by the outer pipe section. The spaces surrounded by the inner pipe section and the outer pipe section are independent of each other. A first annulus 15 is formed between the inner pipe section and the outer pipe section, and the injection string is used to form a second annulus 14 between the casing 13. The outer pipe section spans the upper oil layer. In this embodiment, there are three oil layers in the oil well, namely, an upper oil layer 30, a middle oil layer 40, and a lower oil layer 50. In this embodiment, the upper oil layer refers to the upper oil layer 30. In other embodiments, if there are four oil layers in the oil well, the first oil layer and the second oil layer can both indicate upper oil layers, that is, the upper oil layer does not necessarily indicate the topmost oil layer, but can also indicate multiple topmost oil layers.

[0029] like Figure 3 As shown, in order to facilitate the connection of the double-layer pipe segment with the upper single-layer pipe segment 1 and the lower single-layer pipe segment 16, the injection column includes a double pipe joint 2, and the upper single-layer pipe segment 1 is changed into a double-layer pipe segment at the double pipe joint 2. Specifically, the double pipe joint 2 is tubular, and the diameters of the inner cavity of the double pipe joint 2 are larger at both ends and smaller in the middle. A first connection structure 22 is provided on the inner wall of the double pipe joint 2, and the first connection structure 22 is convenient for fixed connection with the internal pipe segment. In this embodiment, the first connection structure 22 is a threaded segment, and the internal pipe segment is threadedly assembled with the first connection structure 22. The double pipe joint 2 is divided into the upper single-layer pipe segment 1 and the lower external pipe segment by the first connection structure 22. The external pipe segment is divided into multiple segments, and the external pipe segment on the double pipe joint 2 is only one of them. Therefore, a first threaded segment 23 is also provided on the external pipe segment, so as to facilitate connection with other external pipe segments. A third threaded segment 21 is also provided above the double pipe joint 2, so as to facilitate connection with the upper single-layer pipe segment 1. Of course, in other embodiments, the first connection structure 22 may also be provided as an interference fit plug-in section. Alternatively, in other embodiments, the first threaded section 23 may no longer be provided, and the external pipe section may be welded to the double pipe joint 2. Alternatively, in other embodiments, the double pipe joint 2 may no longer be provided, and the external pipe section may be directly welded to the outside of the internal pipe section.

[0030] Since the length required to be extended in the polymer injection well is long, in order to facilitate processing and manufacturing, that is, to facilitate assembly, the internal pipe section has multiple sections. The internal pipe section also includes a small oil pipe 5 located below the double pipe joint 2, the upper end of the small oil pipe 5 is threadedly assembled with the first threaded section 23, and another internal pipe section is arranged below the small oil pipe 5.

[0031] like Figure 5As shown, the injection column also includes an inserter 9 located below the double pipe joint 2. The inserter 9 includes an inserter main body 92. The inserter main body 92 is a tubular structure. A second connection structure 94 is provided on the inner wall of the inserter main body 92, and the second connection structure 94 is fixedly connected to the internal pipe segment. Specifically, the second connection structure 94 is a threaded section. The inserter 9 is divided into an external pipe segment located above and a lower single-layer pipe segment 16 along the second connection structure 94. A second threaded section 93 is also provided on the external pipe segment of the inserter 9 to facilitate the connection of other external pipe segments. Since the diameter of the external pipe segment is larger than the diameter of the internal pipe segment, the diameter of the second connection structure 94 is smaller than the diameter of the second threaded section 93. In order to install the oil pipe, a fourth threaded section 95 for connecting other lower single-layer pipe segments 16 is also provided at the end of the inserter 9 located at the lower single-layer pipe segment 16. Of course, in other embodiments, the second connection structure 94 can also be set as a plug-in section installed by interference fitting. Alternatively, in other embodiments, the second threaded section 93 may not be provided, and the external pipe section may be welded to the outer peripheral surface of the tube inserter 9. Alternatively, in other embodiments, the tube inserter 9 may not be provided, and the external pipe section may be directly welded to the outside of the internal pipe section.

[0032] The connection of the external pipe segment can be achieved through the inserter 9 and the double pipe joint 2. However, the internal pipe segment also needs to be connected. During the installation process, it is impossible to screw the internal and external pipe segments at the same time. Therefore, in this embodiment, the external pipe segment is set to be installed by threaded assembly, and a plug-in segment is set on the internal pipe segment so that different internal pipe segments can rotate with each other. In addition, the form of threaded connection of the external pipe segment and plug-in connection of the internal pipe segment is also convenient for fixing and limiting the internal pipe segment to avoid the internal pipe segment falling during use. Of course, in other embodiments, the internal pipe segment can also be set as a plurality of pipe segments threadedly connected to each other, and the external pipe segment can be set to be plugged into each other.

[0033] like Figure 4 As shown, the internal pipe section includes a first plug-in section and a second plug-in section 91 that are plugged into each other, wherein the first plug-in section is threadedly connected to the small oil pipe 5, and the second plug-in section 91 is threadedly connected to the second threaded section 93 on the inserter 9. After the threaded connection of these two places is completed, the first plug-in section is inserted into the second plug-in section 91. In order to achieve a sealed connection between the first plug-in section and the second plug-in section 91, a sealing assembly is provided on the first plug-in section, and a sealed connection between the first plug-in section and the second plug-in section 91 is achieved by the sealing assembly. Of course, in other embodiments, the second plug-in section 91 may also be provided inside the second plug-in section 91. Alternatively, in other embodiments, the sealing assembly may also be provided on the inner wall of the second plug-in section 91. Alternatively, in other embodiments, only one set of sealing assemblies may also be provided.

[0034] Specifically, Figure 4 As shown, the first plug-in section includes a first plug-in section body 81, and a raised section protruding from the first plug-in section body 81 is also provided on the first plug-in section body 81. In order to achieve a sealing effect, two groups of sealing components are provided, namely a first sealing component 82 and a second sealing component 85. Both ends of each sealing component are provided with raised sections. In order to facilitate sealing, the raised sections are used to squeeze the first sealing component 82 and the second sealing component 85 so that the first sealing component 82 and the second sealing component 85 expand outward to achieve better sealing. A small diameter section is provided on the first plug-in section body 81, and the small diameter section also forms a stage on the first plug-in section body 81, and the stage forms a third raised section. The first sealing component 82 is sleeved on the small diameter section, and then the first raised section 84 is threadedly assembled on the small diameter section. The first sealing component 82 expands outward through the squeezing of the first raised section 84 and the third raised section. A small diameter section is also provided at one end of the first protruding section 84 away from the first sealing component 82, and the second sealing component 85 is provided on the small diameter section of the first protruding section 84. In order to realize the extrusion seal of the second sealing component 85, a second protruding section 87 is also provided on the small diameter section of the first protruding section 84, and an inclined guide surface is provided at one end of the second protruding section 87 away from the second sealing component 85, so as to facilitate the installation of the first plug-in section. In addition, a first sealing ring 83 is also provided between the first protruding section 84 and the first plug-in section body 81, and a second sealing ring 86 is also provided between the first protruding section 84 and the second protruding section 87.

[0035] Of course, in other embodiments, the third protruding section may be movably arranged on the first plug-in section body 81, and when in use, the third protruding section is reversely screwed to complete the sealing of the first sealing component 82. Alternatively, in other embodiments, all protruding sections are fixedly arranged on the first plug-in section body 81, and in this case, the first sealing component 82 and the second sealing component 85 are no longer squeezed and sealed. Alternatively, in other embodiments, the sealing component may no longer be arranged, and the first plug-in section and the second plug-in section 91 may be interference fit.

[0036] like Figure 2As shown, in order to realize the injection of polymer into different oil layers, two connecting structures connecting the first annulus 15 and the second annulus 14 are provided on the external pipe section, and the two connecting structures also constitute the upper connecting structure 3 and the lower connecting structure 7 respectively, wherein the upper connecting structure 3 constitutes the injection port, and the lower connecting structure 7 constitutes the output port. In order to prevent the polymer from directly entering the upper oil layer 30, an upper packer 4 and a middle packer 6 are provided between the upper connecting structure 3 and the lower connecting structure 7 on the external pipe section, wherein the upper packer 4 is located above the upper oil layer 30, and the middle packer 6 is located below the upper oil layer 30, thereby sealing the upper oil layer 30. The lower connecting structure 7 needs to be injected into the middle layer, and in order to avoid mutual interference between the oil layers, a lower packer 10 is provided between the middle oil layer 40 and the lower oil layer 50, and the lower connecting structure 7 is provided between the middle packer 6 and the lower packer 10. A bottom connecting structure 11 is also provided below the lower packer 10, and the bottom connecting structure 11 is located on the lower single-layer pipe section 16, so as to facilitate the injection of the lower oil layer 50 through the bottom connecting structure 11. A wire plug 12 is also provided at the bottom of the lower single-layer pipe section 16. It is worth noting that in this embodiment, the upper connecting structure 3, the lower connecting structure 7 and the bottom connecting structure 11 are all screen pipes. Of course, in other embodiments, other connecting forms can also be provided, such as directly drilling holes on the pipeline.

[0037] like Figure 2 As shown, as oil production proceeds, when the middle oil layer 40 and the lower oil layer 50 need to be injected to supplement the pressure while the upper oil layer 30 does not need to be injected, polymer is injected into the upper single-layer pipe section 1 and the second annulus 14. The polymer in the upper single-layer pipe section 1 flows into the lower single-layer pipe section 16 through the double pipe joint 2 and the internal pipe section and finally through the inserter 9, and finally the polymer is injected into the lower oil layer 50 through the bottom connecting structure 11. The polymer injected into the second annulus 14 enters the first annulus 15 through the upper connecting structure 3, and then flows out of the lower connecting structure 7 and flows into the middle oil layer 40, thereby avoiding the uppermost oil layer and injecting the polymer into the lower oil layer.

[0038] 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 polymer injection well injection string, characterized by: The invention comprises a double-layer pipe section located in the middle of the distribution pipe string for polymer injection well, an upper single-layer pipe section and a lower single-layer pipe section respectively located on the upper and lower sides of the double-layer pipe section, the double-layer pipe section comprises an outer pipe section and an inner pipe section connecting the upper single-layer pipe section and the lower single-layer pipe section, a first annulus is formed between the inner pipe section and the outer pipe section, the distribution pipe string for polymer injection well is used to form a second annulus between the inner pipe section and the outer pipe section, an upper connecting structure and a lower connecting structure which are arranged at intervals and are used to connect to the first annulus and the second annulus are arranged on the outer pipe section, a packer for sealing the upper oil layer is also arranged between the two connecting structures on the outer pipe section, a bottom connecting structure connected to the second annulus is also arranged on the lower single-layer pipe section, a packer is arranged between the bottom connecting structure and the lower connecting structure to connect the lower connecting structure and the bottom connecting structure to different oil layers.

2. The polymer injection well separation pipe string according to claim 1, characterized in that: The polymer injection well injection string comprises a double pipe joint, which comprises a first connection structure arranged on the inner wall for connecting the internal pipe section, so as to divide the double pipe joint into an upper single-layer pipe section and an external pipe section along the first connection structure.

3. The polymer injection well separation pipe string according to claim 2, characterized in that: The end of the double pipe joint located at the outer pipe section is also provided with a first threaded section, and the outer pipe section includes multiple sections of pipe body.

4. The polymer injection well separation injection string according to any one of claims 1 to 3, characterized in that: The polymer injection well injection string includes a pipe inserter, and a second connection structure for connecting the internal pipe section is also arranged on the inner wall of the pipe inserter, so as to divide the pipe inserter into a lower single-layer pipe section and an external pipe section along the second connection structure.

5. The polymer injection well separation pipe string according to claim 4, characterized in that: The tube introducer is provided with a second threaded section connected to the external pipe section, and the diameter of the second connecting structure is smaller than the diameter of the second threaded section.

6. The polymer injection well separation injection string according to any one of claims 1 to 3, characterized in that: The upper end of the external pipe segment is threadedly connected to the upper single-layer pipe segment or the internal pipe segment, and the lower end of the external pipe segment is threadedly connected to the lower single-layer pipe segment or the internal pipe segment. The internal pipe segment includes a first plug-in segment and a second plug-in segment that are plugged into each other.

7. The polymer injection well separation injection string according to claim 6, characterized in that: A sealing assembly is provided between the first plug-in section and the second plug-in section to ensure a sealed connection between the first plug-in section and the second plug-in section.

8. The polymer injection well separation injection string according to claim 7, characterized in that: The first plug-in section is inserted into the second plug-in section, a raised section is provided on the first plug-in section, at least one raised section is threadedly assembled on the surface of the first plug-in section, and the sealing component is arranged between two adjacent raised sections so that the sealing component can expand and deform outward under the extrusion of the raised section.

9. The polymer injection well separation injection string according to claim 8, characterized in that: The sealing components are provided in at least two groups, and the same convex section is provided between two adjacent sealing components so that the end surfaces at both ends of the convex section can press the two adjacent sealing components respectively.

10. The polymer injection well separation injection string according to any one of claims 1 to 3, characterized in that: The upper connecting structure, the lower connecting structure and the bottom connecting structure are all sieve tubes.

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