Casing annulus fluid injection device and method

Abstract

The invention relates to the technical field of natural gas development, in particular to a casing annulus fluid injection device and method.The device comprises a connecting cylinder, a plunger and a conveying assembly, the connecting cylinder is provided with a first channel allowing the plunger to linearly slide, the plunger is in sealed connection with the inner wall of the first channel, and the two ends of the plunger are provided with an inlet and an outlet respectively; the plunger is provided with a second channel, the second channel is provided with an arc-shaped corner, the conveying assembly is connected with the inner wall of the second channel in a sealed mode, and one end of the conveying assembly extends into the second channel from the inlet and extends out of the outlet to be used for descending in the casing annulus and injecting fluid. The plugging agent can be injected at a fixed point under the conditions that the casing annulus is under pressure and gas well production is not affected, the casing annulus air channeling plugging effect is improved, and simple, convenient and low-cost plugging operation of the casing annulus is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas development, and more particularly to a casing annulus fluid injection device and method. Background Art

[0002] During the natural gas development process, as the exploitation time increases, the problem of annular pressure in gas wells increases year by year, causing safety hazards in many gas wells.

[0003] At present, there are two main methods to solve the problem of casing annulus pressure: one is to use the well repair method, pull out the production tubing, and drill holes in the production casing to squeeze plugging agents to plug the gas channel. This method is expensive and has a low success rate, which affects the normal production of gas wells, especially for low-pressure sensitive gas reservoirs. After the well repair, it will affect the gas well production capacity and cause gas well production loss. The other is to inject plugging agents into the casing annulus or inject plugging agents through the insertion method to plug the casing annulus air channel. Among them, the general injection of plugging agents has problems such as difficulty in injection, fluid contamination of plugging agents in the annulus, difficulty in determining the plugging position, and low success rate; the insertion method is difficult to lower the plugging pipe to the required depth due to the 90° angle between the casing valve and the casing annulus, the small annular gap, and the presence of casing couplings, which affects the plugging effect after the injection of plugging agents and subsequent construction. Summary of the invention

[0004] In order to solve the problem of difficulty in plugging gas channel in the prior art, the present invention proposes a casing annulus fluid injection device and method, which can inject plugging agent at a fixed point under the condition that the casing annulus is pressurized and does not affect the production of the gas well, thereby improving the plugging effect of casing annulus air channeling and realizing simple and low-cost plugging operation of the casing annulus.

[0005] To achieve the above-mentioned purpose, the technical solution of the present invention is a casing annulus fluid injection device, comprising a connecting tube, a plunger and a conveying assembly, the connecting tube having a first channel for the plunger to slide in a straight line, the plunger extending from one end of the connecting tube into the first channel and being sealedly connected to the inner wall of the first channel, the two ends of the plunger are respectively provided with mutually perpendicular inlets and outlets, the plunger is provided with a second channel respectively connected to the inlet and outlet, the second channel has an arc-shaped corner, the conveying assembly is sealedly connected to the inner wall of the second channel, one end of the conveying assembly extends from the inlet into the second channel and extends from the outlet, so as to descend in the casing annulus and inject fluid.

[0006] In the technical solution, one end of the connecting tube is connected to the first casing valve of the casing annulus. After opening the first casing valve, the plunger can be pushed into the casing annulus. At this time, the first channel and the second channel are both connected to the casing annulus. The outlet position of the plunger is adjusted to align with the casing annulus. Then, the conveying assembly enters the casing annulus and moves downward under the guidance of the second channel. During this process, the conveying assembly can achieve a 90° turn when passing a corner. During the downward process, a pump is used to pass pressurized anticorrosive liquid into the conveying assembly to clean the wall of the casing replacement. When the conveying assembly moves downward to the position of the gas channeling channel, the plugging agent is delivered to the position of the gas channeling channel through the conveying assembly for plugging. During the plugging operation, since the plunger and the conveying assembly in the first channel and the second channel are both sealed, the device works under the condition that the casing annulus is pressurized and does not affect the production of the gas well.

[0007] As a preferred solution, in order to reduce the friction between the conveying component and the second channel, the corners of the second channel are smooth arc surfaces, and the corners are provided with a plurality of rolling elements arranged at intervals along the arc direction. The rolling elements are rollers or balls. The rolling elements at the corners can convert the rigid friction of the conveying component into rolling friction, thereby reducing the friction resistance of the conveying component during descent and recovery, and can also reduce the wear of the conveying component.

[0008] As a preferred solution, in order to achieve long-distance transportation of the fluid, the conveying assembly includes a conveying pipe and a traction head adapted to the inner diameter of the second channel, one end of the conveying pipe is connected to the traction head, and the traction head is provided with a spray hole connected to the conveying pipe. The preservative liquid is sprayed from the spray hole to the oblique rear of the conveying assembly to push the conveying assembly downward.

[0009] As a preferred solution, the injection hole and the conveying pipe are arranged at an angle α, and the angle α is 40° to 50°. At this angle setting, when the pressurized fluid is ejected from the injection hole, it can push the traction head to drive the conveying pipe downward in the casing annulus, and at the same time, the pipe wall of the casing annulus can be cleaned.

[0010] As a preferred solution, in order to achieve a sealed connection between the first channel and the plunger, the outer wall of the plunger is provided with a plurality of first grooves arranged at intervals along its axial direction, and each of the first grooves is provided with a first sealing ring that cooperates with the first channel. When the plunger slides in the first channel, the first sealing ring can seal the device, so that the device can operate under pressure in the casing annulus.

[0011] As a preferred solution, in order to achieve a sealed connection between the second channel and the conveying assembly, the second channel is provided with a second groove, in which a pressure ring and a second sealing ring cooperating with the plunger are provided, and a push rod is screwed on the end of the plunger close to the inlet, and one end of the push rod extends into the second groove and presses the pressure ring and the second sealing ring. When the push rod is screwed into the second groove and presses the pressure ring and the second sealing ring, the sealing ring undergoes elastic deformation and is pressed against the outer wall of the conveying assembly to achieve sealing.

[0012] As a preferred solution, in order to improve the sealing performance, the pressure ring and the second sealing ring are respectively provided in plurality, and the plurality of pressure rings and the second sealing rings are alternately arranged along the axial direction of the second channel. The pressure ring is used to squeeze the second sealing ring so that the plurality of sealing rings are deformed at the same time and pressed against the outer wall of the conveying component.

[0013] To achieve the above object, a casing annulus fluid injection method of the technical solution uses the above casing annulus fluid injection device, wherein the two sides of the casing annulus are respectively provided with a first casing valve and a second casing valve in communication, and comprises the following steps:

[0014] S1: Connect the closed drain tank to the first casing valve, open the first casing valve to release the pressure until the pressure in the casing annulus is stable;

[0015] S2: Connect one end of the connecting tube to the second sleeve valve and perform a sealing test on the conveying assembly;

[0016] S3: Open the second casing valve, push the plunger into the casing annulus through the second casing valve, adjust the outlet of the plunger to correspond to the casing annulus, and push the conveying assembly out of the outlet along the second channel by at least 5m;

[0017] S4: Use a pump to inject anticorrosive liquid into the conveying assembly and slowly pressurize it to slowly move the conveying assembly down until the conveying assembly reaches the gas channel position of the casing annulus, and inject 0.8m 3 ~1.2m 3 After the plugging agent is added, the anti-corrosion liquid is continuously injected to push the plugging agent to the gas channel position;

[0018] S5: After the plugging agent is injected, the delivery assembly is retracted into the second channel, and then the plunger is retracted into the first channel, and the first casing valve and the second casing valve are closed.

[0019] As a preferred solution, in order to ensure the smooth delivery of the fluid, in step S2, the sealing test of the delivery component is: the anti-corrosion liquid is delivered to the delivery device by a pump and pressurized to 1.5 times greater than the pressure in the casing annulus, and stabilized at this pressure for at least 10 minutes.

[0020] As a preferred solution, in step S4, the winch is connected to one end of the conveying assembly and controls the downward speed of the conveying assembly to be less than 10m / min, and the winch can control the downward speed of the conveying assembly.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The device of the present invention can realize a 90° turn of the conveying assembly through the arc-shaped corner and the rolling element arranged at the corner. At the same time, the rolling element can convert the rigid friction of the conveying assembly into rolling friction, thereby reducing the friction resistance of the conveying assembly during descent and recovery, and also reducing the wear of the conveying assembly.

[0023] 2. The first and second channels are sealed by the first and second sealing members, so that the device can inject plugging agents at a fixed point when the casing annulus is pressurized and does not affect the production of the gas well, thereby improving the plugging effect of air channeling in the casing annulus and realizing a simple and low-cost plugging operation of the casing annulus.

[0024] 3. By injecting pressurized fluid into the conveying pipe, the fluid is ejected from the inclined injection holes set on the traction head to push it downward, and at the same time, it can clean the pipe wall of the casing annulus during the downward process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the casing annulus fluid injection device of the present invention;

[0026] Figure 2 is a schematic diagram of the structure of the conveying assembly;

[0027] Figure 3 It is a schematic diagram of the installation of the casing annulus fluid injection device of the present invention;

[0028] Figure 4 It is a working schematic diagram of the casing annulus fluid injection device of the present invention;

[0029] Figure 5 The present invention is a flow chart of the casing annulus fluid injection method.

[0030] In the figure: connecting cylinder 1; first channel 11; plunger 2; second channel 21; corner 211; rolling element 2111; inlet 22; outlet 23; first groove 24; first sealing ring 241; second groove 25; second sealing ring 251; pressure ring 252; push rod 253; conveying assembly 3; conveying pipe 31; traction head 32; joint 33; screw 4; casing annulus 5; first casing valve 51; second casing valve 52; closed discharge tank 6; winch 7. DETAILED DESCRIPTION

[0031] The drawings are only for illustrative purposes and cannot be construed as limiting the present invention. To better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are only for illustrative purposes and cannot be construed as limiting the present invention.

[0032] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "long", "short" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0033] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0034] Embodiment 1:

[0035] like Figures 1 to 4 As shown, a casing annulus fluid injection device is provided, comprising a connecting tube 1, a plunger 2 and a conveying assembly 3, wherein the connecting tube 1 has a first channel 11 for the plunger 2 to slide in a straight line, the plunger 2 extends from one end of the connecting tube 1 into the first channel 11 and is sealedly connected to the inner wall of the first channel 11, one side of the plunger 2 and one side of the connecting tube 1 are respectively provided with matching flanges, the flange of the plunger 2 and the flange of the connecting tube 1 are connected by a screw 4 to adjust the position of the plunger 2 in the first channel 11, and both ends of the plunger 2 An inlet 22 and an outlet 23 are respectively provided which are perpendicular to each other. The plunger 2 is provided with a second channel 21 which is respectively connected with the inlet 22 and the outlet 23. The corner 211 of the second channel 21 is a smooth arc surface. The second channel 21 has an arc-shaped corner 211. One end of the conveying component 3 is connected with an inclined injection hole 321 for pushing the conveying component 3 to move. One end of the conveying component 3 extends from the inlet 22 into the second channel 21 and extends from the outlet 23. The conveying component 3 is sealed and connected to the inner wall of the second channel 21.

[0036] In this embodiment, the device can operate under the condition that the casing annulus is pressurized and does not affect the production of the gas well. If the gas well is shut down, there is no need to consider the problem of casing annulus pressurization. The plunger 2 can be directly connected to the second casing valve 52 through its flange, and then pressurized fluid is introduced into the conveying component 3 to provide it with downward power.

[0037] Specifically, Figure 2 As shown, the conveying assembly 3 includes a conveying pipe 31 and a traction head 32 adapted to the inner diameter of the second channel 21 , one end of the conveying pipe 31 is connected to the traction head 32 , and the injection hole 321 is provided on the traction head 32 and communicated with the conveying pipe 31 .

[0038] In this embodiment, the traction head 32 is connected to the delivery pipe 31 through a joint 33, wherein the delivery pipe 31 is a bendable hose.

[0039] Specifically, the injection hole 321 and the delivery pipe 31 are arranged at an angle α, and the angle α is 40° to 50°.

[0040] In this embodiment, the angle α is preferably 45°. The injection holes 321 at this angle provide power for downward movement by injecting fluid backwards, and can also clean the inner wall of the casing annulus 5.

[0041] Specifically, the outer wall of the plunger 2 is provided with a plurality of first grooves 24 spaced apart along the axial direction thereof, and each of the first grooves 24 is provided with a first sealing ring 241 matched with the first channel 11 .

[0042] In this embodiment, six annular first grooves 24 are provided on the outer wall of the plunger 2 , and the outer diameter of the first sealing ring 241 is slightly larger than the inner diameter of the first channel 11 .

[0043] Specifically, the second channel 21 is provided with a second groove 25, and the second groove 25 is provided with a pressure ring 252 and a second sealing ring 251 that cooperate with the plunger 2. The end of the plunger 2 close to the inlet 22 is screwed with a push rod 253, and one end of the push rod 253 extends into the second groove 25 and presses the pressure ring 252 and the second sealing ring 251.

[0044] In this embodiment, the pressure ring 252 has a high hardness and is not easily deformed, and can effectively squeeze the second sealing ring 251 to deform it, thereby enhancing the sealing performance.

[0045] Specifically, a plurality of the pressure rings 252 and the second sealing rings 251 are provided respectively, and the plurality of pressure rings 252 and the second sealing rings 251 are alternately arranged along the axial direction of the second channel 21 .

[0046] In this embodiment, the pressing ring 252 is a hollow structure, the outer wall of the pressing ring 252 is provided with an external thread, the inner wall of the second groove 25 is provided with an internal thread adapted thereto, and the pressing ring 252 is threadedly connected to the second groove 25 .

[0047] Embodiment 2:

[0048] This embodiment is similar to Embodiment 1, except that, in this embodiment, Figure 1 , 3 As shown in FIG. 4 , the corner 211 is provided with a plurality of rolling elements 2111 spaced apart along the arc direction thereof, and the rolling elements 2111 are rollers or balls.

[0049] In this embodiment, in order to facilitate processing, the rolling member 2111 is preferably a roller, and a plurality of rotating shafts are rotatably connected along the upper and lower side walls of the corner 211, and the plurality of rollers are respectively mounted on the rotating shafts. Under the guidance of the rollers, a 90° turn of the conveying component 3 is achieved, and the friction between the conveying component 3 and the corner 211 during the downward process can be reduced.

[0050] Embodiment 3:

[0051] like Figure 4 , 5 As shown, this embodiment provides a casing annulus fluid injection method, using the above-mentioned casing annulus fluid injection device, wherein the two sides of the casing annulus 5 are respectively provided with a first casing valve 51 and a second casing valve 52 that are connected, and is characterized in that it includes the following steps:

[0052] S1: Connect the closed drain tank 6 to the first casing valve 51, and open the first casing valve 51 to release the pressure until the pressure in the casing annulus 5 is stable;

[0053] S2: Connect one end of the connecting tube 1 to the second sleeve valve 52 and perform a sealing test on the conveying assembly 3;

[0054] S3: Open the second casing valve 52, push the plunger 2 into the casing annulus 5 through the second casing valve 52, adjust the outlet 23 of the plunger 2 to correspond to the casing annulus 5, and push the conveying assembly 3 out of the outlet 23 along the second channel 21 for at least 5m;

[0055] S4: inject the anticorrosive liquid into the conveying component 3 through the pump and slowly pressurize it to slowly move the conveying component 3 down until the conveying component 3 reaches the gas channel position of the casing annulus 5, and inject 0.8m 3 ~1.2m 3 After the plugging agent is added, the anti-corrosion liquid is continuously injected to push the plugging agent to the gas channel position;

[0056] S5: After the plugging agent is injected, the delivery assembly 3 is retracted into the second channel 21 , and then the plunger 2 is retracted into the first channel 11 , and the first sleeve valve 51 and the second sleeve valve 52 are closed.

[0057] Specifically, in step S2, the sealing test of the conveying component 3 is as follows: the antiseptic liquid is conveyed to the conveying device by a pump and pressurized to a pressure greater than 1.5 times the pressure in the casing annulus 5, and stabilized at the pressure for at least 10 minutes.

[0058] Specifically, in step S4, the winch 7 is connected to one end of the conveying assembly 3 and the downward speed of the conveying assembly 3 is controlled to be less than 10 m / min.

[0059] The working process of the casing annulus fluid injection method of the present invention is as follows: when the first casing valve 51 is closed, the closed drain tank 6 is connected through a pipeline, and then the first casing valve 51 is opened to release the annulus pressure to a stable pressure of 0.9 MPa, and after the delivery pipe 31 is connected to the traction head 32 through the joint 33, it is inserted into the second channel 21 from the inlet 22, and the push rod 253 is rotated to achieve the sealing between the delivery pipe 31 and the second channel 21, and the plunger 2 is inserted into the first channel 11 and connected to the connecting tube 1 through the screw 4, and when the second casing valve 52 is closed, the end of the connecting tube 1 away from the screw 4 is connected to the second casing valve 52, and after the sealing test of the device is completed, the second casing valve 52 is opened, and the screw 4 is rotated to make the plunger 2 One end is inserted into the casing annulus 5 and the outlet 23 is made vertically downward. The delivery pipe 31 is manually inserted into the casing annulus 5 for more than 5m. The delivery pipe 3 is injected with 2MPa of anticorrosive liquid through the pump. As the anticorrosive liquid is ejected from the injection hole 321 to the rear, it provides traction for the downward movement of the delivery pipe 31. The downward speed of the delivery pipe 31 is controlled to be 5m / min through the winch 7. If the downward process encounters resistance and cannot go down, it stays at this position to maintain the injection of 2MPa of anticorrosive liquid. After maintaining for 2min, stop the pump, lift the delivery pipe 31 by 15m through the winch 7, start the pump and slowly pressurize it to 2.5MPa, control the delivery pipe 31 to slowly descend at a speed of 3m / min, and after reaching the specified depth, inject 1m 3 The plugging agent is then pumped in, and the anti-corrosion liquid with a pressure of 2 MPa is then continued to be pumped in to push the plugging agent to the specified depth. After the plugging agent is injected, the hose is slowly recovered, the traction head 32 is retracted into the second channel 21, the plunger 2 is retracted into the first channel 11, and the first casing valve 51 and the second casing valve 52 are closed.

[0060] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

[0061] Obviously, the above embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A casing annulus fluid injection device, characterized in that: The invention comprises a connecting tube (1), a plunger (2) and a conveying assembly (3), wherein the connecting tube (1) has a first channel (11) for the plunger (2) to slide linearly, the plunger (2) extends from one end of the connecting tube (1) into the first channel (11) and is sealedly connected to the inner wall of the first channel (11), the two ends of the plunger (2) are respectively provided with an inlet (22) and an outlet (23) perpendicular to each other, the plunger (2) is provided with a second channel (21) respectively connected to the inlet (22) and the outlet (23), the second channel (21) has an arc-shaped corner (211), the conveying assembly (3) is sealedly connected to the inner wall of the second channel (21), one end of the conveying assembly (3) extends from the inlet (22) into the second channel (21) and extends from the outlet (23) so as to descend in the casing annulus (5) and inject fluid.

2. A casing annulus fluid injection device according to claim 1, characterized in that: The corner (211) of the second channel (21) is a smooth arc surface, and a plurality of rolling elements (2111) are arranged at intervals along the arc direction at the corner (211), and the rolling elements (2111) are rollers or balls.

3. The casing annulus fluid injection device according to claim 1, characterized in that: The conveying assembly (3) comprises a conveying pipe (31) adapted to the inner diameter of the second channel (21) and a traction head (32); one end of the conveying pipe (31) is connected to the traction head (32); and the traction head (32) is provided with a spray hole (321) connected to the conveying pipe (31).

4. The casing annulus fluid injection device according to claim 3, characterized in that: The injection hole (321) and the delivery pipe (31) are arranged at an angle α, and the angle α is 40° to 50°.

5. The casing annulus fluid injection device according to claim 1, characterized in that: The outer wall of the plunger (2) is provided with a plurality of first grooves (24) arranged at intervals along its axial direction, and each of the first grooves (24) is provided with a first sealing ring (241) that cooperates with the first channel (11).

6. The casing annulus fluid injection device according to claim 1, characterized in that: The second channel (21) is provided with a second groove (25), and a pressure ring (252) and a second sealing ring (251) that cooperate with the plunger (2) are provided in the second groove (25); a push rod (253) is screwed to one end of the plunger (2) close to the inlet (22), and one end of the push rod (253) extends into the second groove (25) and presses the pressure ring (252) and the second sealing ring (251).

7. The casing annulus fluid injection device according to claim 6, characterized in that: A plurality of the pressure rings (252) and the second sealing rings (251) are provided respectively, and the plurality of pressure rings (252) and the second sealing rings (251) are alternately arranged along the axial direction of the second channel (21).

8. A method for injecting fluid into the casing annulus, using the casing annulus fluid injection device according to any one of claims 1 to 7, wherein: A first casing valve (51) and a second casing valve (52) are respectively connected on both sides of the casing annulus (5), and the method is characterized in that the method comprises the following steps: S1: Connect the closed drain tank (6) to the first casing valve (51), and open the first casing valve (51) to release the pressure until the pressure in the casing annulus (5) is stable; S2: connecting one end of the connecting tube (1) to the second sleeve valve (52) and performing a sealing test on the conveying assembly (3); S3: Open the second casing valve (52), push the plunger (2) into the casing annulus (5) through the second casing valve (52), adjust the outlet (23) of the plunger (2) to correspond to the casing annulus (5), and push the conveying assembly (3) out of the outlet (23) along the second channel (21) by at least 5 m; S4: injecting antiseptic liquid into the conveying component (3) through a pump and slowly pressurizing it to slowly move the conveying component (3) down until the conveying component (3) reaches the gas channel position of the casing annulus (5), injecting 0.8m 3 ~1.2m 3 After the plugging agent is added, the anti-corrosion liquid is continuously injected to push the plugging agent to the gas channel position; S5: After the plugging agent is injected, the delivery assembly (3) is retracted into the second channel (21), and then the plunger (2) is retracted into the first channel (11), and the first casing valve (51) and the second casing valve (52) are closed.

9. The method for injecting fluid into casing annulus according to claim 8, characterized in that: In step S2, the sealing test of the conveying component (3) is as follows: the antiseptic liquid is conveyed to the conveying device by a pump and pressurized to a pressure greater than 1.5 times the pressure in the casing annulus (5), and maintained at this pressure for at least 10 minutes.

10. The method for injecting fluid into casing annulus according to claim 8, characterized in that: In step S4, a winch (7) is connected to one end of the conveying assembly (3) and the downward speed of the conveying assembly (3) is controlled to be less than 10 m / min.

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