Sand washing and plug removing device for double-string coiled tubing

Abstract

The utility model relates to a double tubular column coiled tubing sand washing and unblocking device which comprises a flow divider, an inner tube, an outer tube, a double jet flow device and a fastening head, the flow divider and the double jet flow device are connected through the inner tube and the outer tube respectively, and the double jet flow device and the outer tube are connected, fixed and sealed through the fastening head. And the inner pipe and the outer pipe form a complete communication passage through the flow divider and the double jet devices. According to the working principle, ground power fluid enters from the outer pipe opening, enters the outer pipe through the second channel, then enters the double-jet-jet device through the third channel and is jetted out through the first jet pipe, negative pressure is formed at the position of the throat pipe, meanwhile, the power fluid is also jetted out through the second jet pipe at the same time, sand, dirt and the like at the well bottom are stirred and flushed up, and the well bottom is protected. Well fluid stirred and flushed up is sucked into the throat pipe through the fourth channel, enters the inner pipe, ascends and is discharged through the first channel and the inner pipe opening.

Description

Technical field:

[0001] The invention relates to the technical field of sand flushing and unblocking of oil and gas wells, and in particular to a method and device for sand flushing and unblocking of double-pipeline continuous oil pipes. Background technology:

[0002] The existing sand-producing oil and gas horizontal wells, coalbed methane horizontal wells and low-pressure leakage deep wells with serious sand production, mud, sand, water and coal powder are often produced during the whole production process, especially in loose sand-producing formations and coal seams put into production by fracture. Due to the deposition and accumulation of sand, mud and coal powder at the bottom of the horizontal well, the production channel and the normal raising and lowering of the production string will be seriously blocked. For such oil and gas formations and coal seams with negative pressure, underpressure and those not suitable for positive pressure flushing, it is difficult to use the existing sand flushing and unblocking technologies and tools to prevent the power fluid from flowing back into the formation during the sand flushing operation, causing damage to the reservoir, leading to a sharp drop in production capacity and the risk of sand stuck in the string. The currently commonly used gas foam sand removal has low efficiency and high consumption, and also has construction safety risks. The commonly used hydraulic circulation sand flushing is also difficult to use. For horizontal wells with long horizontal sections and large vertical well positions, it is difficult to pump out the construction string, and the risk of the construction string being stuck by sand is high. The existing double-tube hydraulic jet sand cleaning technology is also inconvenient to connect the double-tube string, the construction pressure is high, and a large construction displacement is required. For wells with long horizontal sections, the construction string is not easy to advance, and sand sedimentation in the pipeline is likely to cause blockage and sand sticking in the string. In addition, the existing jet negative pressure suction device generally adopts a first-level jet and a circular nozzle. When sucking high-sand liquid at a high displacement, it is easy for large particles of sand to block the jet flow channel and the string, resulting in construction pauses and failures. Moreover, the wear on the throat of the jet pump is large, resulting in its service life being short, and it cannot meet the sand flushing and unblocking needs of deep wells, horizontal wells, etc. The invention patent "A two-stage jet negative pressure sand pumping string for oil and gas wells (CN202410751749)" introduces a two-stage relay of a positive circulation jet sand pump and an annular jet sand pump. Through the cooperation of the sand blowing nozzle and the rotary drill bit, the flow rate of the ejected power fluid is less than the suction volume of the annular jet sand pump, thereby ensuring that the oil and gas production well section below the leather cup packer is in a negative pressure state and avoiding the phenomenon of power fluid backflow into the oil and gas reservoir. Although this method proposes a solution to the sand pumping operation of deep wells and horizontal wells and meets the needs of sand flushing and unblocking in deep wells, horizontal wells, etc., it is difficult to implement and it is difficult to achieve the stated purpose. Summary of the invention:

[0003] The purpose of the present invention is to provide a double-string continuous tubing sand flushing and blockage removal method and device for oil wells, shale gas wells or coalbed methane wells with low formation pressure. In this device, fluid or gas is stirred and flushed through a double jet flow device connected to the bottom of the double string to transport sand, scale and other impurities deposited in the wellbore to the ground.

[0004] The device adopts a double-nozzle jet and jet stirring structure and a double-pipeline structure of continuous oil tubing to achieve the purpose of continuous sand flushing in wells with low formation pressure or wells with no-well operation. The device has a simple structure, convenient construction, reliable operation, high efficiency, and a wide range of applications, especially for oil and gas wells with poor wellbore quality or leakage.

[0005] The invention is implemented as follows:

[0006] In a double-column continuous tubing sand flushing and unblocking device mainly composed of a flow divider (3), an inner tube (13), an outer tube (14), a double ejector (16), a fastening joint (19), etc., the flow divider (3) and the double ejector (16) are connected to the outer tube (14) through the inner tube (13), respectively, and the double ejector (16) and the outer tube (14) are connected, fixed and sealed by the fastening joint (19), so that the inner tube (13) and the outer tube (14) form a complete communication passage through the flow divider (3) and the double ejector (16).

[0007] The flow divider (3) is composed of an inner joint (7), an outer joint (10), a pressure cover (1), a spare cap (2), a bearing 1 (5), a bearing 2 (11), a housing (4), a sealing ring 1 (6), a sealing ring 2 (8), a sealing ring 3 (9), a sealing ring 4 (12), etc. The inner joint (7) and the outer joint (10) are sleeved together and fixed in the housing (4) of the flow divider (3) by the pressure cover (1) and the spare cap (2); the bearing 1 (5) and the bearing 2 (11) are respectively installed at the contact surface between the inner joint (7) and the outer joint (10) of the flow divider (3) and the housing (4), so that the housing (4) and the inner joint (7) and the outer joint (10) are connected in a rotating or sliding manner; the inner joint (7) and the outer joint (10) of the flow divider (3) are connected in a rotating or sliding manner. (10) is respectively provided with a sealing ring 2 (8) and a sealing ring 3 (9) for closing the channel 2 (27) on the external joint (10) and isolating it from the outside of the shell (4); a sealing ring 4 (12) on the shell (4) is used to close the outside of the shell (4) and the internal structure; the internal joint (7) on the diverter (3) is connected and communicated with the inner tube (13); the external joint (10) on the diverter (3) is connected and communicated with the outer tube (14); the channel 1 (25) on the internal joint (7) is communicated with the inner tube opening (21) on the pressure cover (1); the channel 2 (27) on the external joint (10) is communicated with the outer tube opening (22) on the shell (4); and the sealing ring 1 (6) on the pressure cover (1) is used to close the channel 1 (25) on the internal joint (7).

[0008] The shell (4) of the flow divider (3) and the internal joint (7) and the external joint (10) therein are connected in a rotating or sliding manner. In this connection state, the fluid entering from the external pipe opening (22) is guided into the external pipe (14) through the second channel (27) on the external joint (10), and the well fluid discharged from the inner pipe (13) is guided into the inner pipe opening (21) through the first channel (25) on the internal joint (7) and then discharged.

[0009] The double ejector (16) is composed of a throat (15), a nozzle 1 (17), a base (18), a nozzle 2 (20), etc. The throat (15), the nozzle 1 (17), and the nozzle 2 (20) are connected to the base (18) respectively. The base (18) is provided with a channel 3 (29), a channel 4 (30), a channel 5 (31), and a channel 6 (33). The channel 3 (29) is a channel for the power fluid to enter the double ejector (16); the channel 4 (30) is a channel for the well fluid to enter; the channel 5 (31) is a power fluid channel for the nozzle 2 (20); and the channel 6 (33) is a power fluid channel for the nozzle 1 (17).

[0010] The throat (15) is connected to the inner tube (13) for communication, and the double ejector (16) is connected, fixed and sealed to the outer tube (14) by a fastening joint (19), thereby forming a communication passage between the inner tube (13) and the outer tube (14).

[0011] The inner nozzle 1 (17) of the double ejector (16) is connected to the channel 6 (33). Its function is to form a negative pressure at the throat (15) by ejecting high-speed fluid, so as to suck the well fluid into the inner tube (13). The second nozzle (20) is connected to the channel 5 (31). Its function is to stir up the sand, scale and other impurities deposited in the wellbore through the second nozzle (20) by using the fluid, and then pass through the channel 4 (30) into the throat (15) together with the well fluid and be discharged from the inner tube (13).

[0012] The characteristics of the present invention are:

[0013] The double-string continuous tubing sand flushing and blockage removal method and device of the present invention realizes continuous sand flushing without well pressure suppression, protects the bottom layer from pollution, etc. during sand flushing, is simple and reliable to operate, is very effective for sand flushing and other maintenance of low-pressure oil and gas wells, shale gas wells, and coalbed methane wells, and is more convenient for sand flushing of horizontal wells, etc. The power fluid for sand flushing is liquid or gas. Description of the drawings:

[0014] Figure 1 The present invention is a schematic diagram of a method and device for sand flushing and unblocking a double-column continuous tubing, which is composed of a continuous tubing inner tube (13), an outer tube (14), a flow divider (3), a double jet flow device (16), a fastening joint (19), etc.

[0015] Figure 2It is a spare cap (2) in the diverter (3) in this embodiment, used for adjusting and fixing components such as the inner joint (7) and the outer joint (10) in the diverter (3).

[0016] Figure 3 The gland (1) in the diverter (3) in this embodiment is used to adjust and fix the internal joint (7) and external joint (10) and other components in the diverter (3). The gland (1) is provided with an internal pipe opening (21) for connecting to an external well fluid discharge pipeline. The gland (1) is provided with a second sealing groove (24) for installing a sealing ring.

[0017] Figure 4 The housing (4) in the flow splitter (3) in this embodiment is used to install and fix the internal joint (7) and external joint (10) and other components in the flow splitter (3). The housing (4) is provided with an external pipe opening (22) for connecting an external power fluid input pipeline. The housing (4) is provided with a sealing groove (23) for installing a sealing ring.

[0018] Figure 5 This is the inner joint (7) in the diverter (3) in this embodiment. The sealing groove three (26) thereon is used to install the sealing ring, the channel one (25) is used to discharge the well fluid, and the bearing one (5) can be installed on the inner joint (7). The bearing one (5) is a standard part.

[0019] Figure 6 This is the external connector (10) in the diverter (3) in this embodiment. The sealing groove (28) thereon is used to install the sealing ring, and the channel (27) is used for the power fluid to enter. The external connector (10) can be installed with the bearing (11), which is a standard part.

[0020] Figure 7 It is the throat (15) in the double ejector (16) in this embodiment.

[0021] Figure 8 It is nozzle one (17) in the double ejector (16) in this embodiment.

[0022] Figure 9 This is the nozzle 2 (20) in the double ejector (16) in this embodiment.

[0023] Figure 10 、 Figure 11 The diagram is a front view and a cross-sectional view of the base (18) in the double ejector (16) in this embodiment. The fixing platform (32) on the base (18) is used for positioning and sealing.

[0024] Figure 12 It is a fastening joint (19) connecting the double ejector (16) and the outer tube (14) in this embodiment.

[0025] Name in the picture:

[0026] 1. Gland, 2. Spare cap, 3. Diverter, 4. Housing, 5. Bearing 1, 6. Seal ring 1, 7. Internal joint, 8. Seal ring 2, 9. Seal ring 3, 10. External joint, 11. Bearing 2, 12. Seal ring 4, 13. Inner tube, 14. Outer tube, 15. Throat, 16. Double ejector, 17. Nozzle 1, 18. Base, 19. Fastening joint, 20. Nozzle 2, 21. Inner tube port, 22. Outer tube port, 23. Seal groove 1, 24. Seal groove 2, 25. Channel 1, 26. Seal groove 3, 27. Channel 2, 28. Seal groove 4, 29. Channel 3, 30. Channel 4, 31. Channel 5, 32. Fixing platform, 33. Channel 6. Specific implementation method:

[0027] The invention will be described in further detail below with reference to the accompanying drawings:

[0028] Reference Figure 1 :

[0029] In a double-column continuous tubing sand flushing and blockage removal method and device composed of a flow divider (3), an inner tube (13), an outer tube (14), a double jet flow device (16), a fastening joint (19), etc., the flow divider (3) and the double jet flow device (16) are connected to the outer tube (14) through the inner tube (13), respectively, and the double jet flow device (16) and the outer tube (14) are connected, fixed and sealed by the fastening joint (19), so that the inner tube (13) and the outer tube (14) form a complete communication passage through the flow divider (3) and the double jet flow device (16).

[0030] Working principle: The ground power fluid enters from the outer pipe port (22), enters the outer pipe (14) through the second channel (27), and then enters the double ejector (16) through the third channel (29), and is ejected from the nozzle one (17), forming a negative pressure at the throat (15). At the same time, the power fluid is also ejected from the second nozzle (20), stirring up the sand and scale at the bottom of the well. The stirred and flushed well fluid is sucked into the throat (15) through the fourth channel (30), enters the inner pipe (13), and then goes up through the first channel (25) and the inner pipe port (21) to be discharged.

Claims

1. A double-string coiled tubing sand flushing and unblocking device, comprising a diverter (3), an inner tube (13), an outer tube (14), a double jet injector (16), and a fastening joint (19), characterized by: The flow splitter (3) and the double ejector (16) are connected to each other through the inner tube (13) and the outer tube (14), respectively, and the double ejector (16) and the outer tube (14) are connected, fixed and sealed by a fastening joint (19), so that the inner tube (13) and the outer tube (14) form a complete communication passage with the double ejector (16) through the flow splitter (3). The flow splitter (3) is composed of an inner joint (7), an outer joint (10), a pressure cover (1), a spare cap (2), a bearing 1 (5), a bearing 2 (11), a housing (4), a sealing ring 1 (6), a sealing ring 2 (8), a sealing ring 3 (9), and a sealing ring 4 (12). The inner joint (7) and the outer joint (10) are sleeved and fixed in the housing (4) of the flow splitter (3) by the pressure cover (1) and the spare cap (2). The contact surfaces of the inner joint (7) and the outer joint (10) of the diverter (3) and the housing (4) are respectively installed with a bearing 1 (5) and a bearing 2 (11); the inner joint (7) and the outer joint (10) of the diverter (3) are respectively installed with a sealing ring 2 (8) and a sealing ring 3 (9); the inner joint (7) on the diverter (3) is connected and communicated with the inner tube (13); the outer joint (10) on the diverter (3) is connected and communicated with the outer tube (14); the channel 1 (25) on the inner joint (7) is communicated with the inner tube opening (21) on the gland (1); the channel 2 (27) on the outer joint (10) is communicated with the outer tube opening (22) on the housing (4); the housing (4) of the diverter (3) and the inner joint (7) and the outer joint (10) therein are connected in a rotating or sliding manner.

2. The dual-string coiled tubing sand flushing and unblocking device according to claim 1, characterized in that: The shell (4) is provided with a sealing groove (23).

3. The dual-string coiled tubing sand flushing and unblocking device according to claim 1, characterized in that: The shell (4) of the flow divider (3) and the inner joint (7) and outer joint (10) therein are connected in a rotating or sliding manner.

4. The dual-string coiled tubing sand flushing and plugging removal device according to claim 1 is characterized by: The inner nozzle (17) of the double ejector (16) forms a negative pressure at the throat (15) by ejecting high-speed fluid, thereby sucking the well fluid into the inner pipe (13).

5. The dual-string coiled tubing sand flushing and unblocking device according to claim 1, characterized in that: The inner nozzle 2 (20) of the double jet flow device (16) uses fluid to stir and flush the sand and scale impurities deposited in the wellbore, and then the sand and scale impurities are flushed out along with the well fluid into the throat pipe (15) and discharged from the inner pipe (13).

6. The dual-string coiled tubing sand flushing and plugging removal device according to claim 1 is characterized by: The base (18) of the double ejector (16) is provided with a third channel (29), a fourth channel (30), a fifth channel (31), and a sixth channel (33). The third channel (29) is a channel for the inlet of the power fluid, the fourth channel (30) is a channel for the inlet of the well fluid, the fifth channel (31) is a channel for the power fluid of the second nozzle (20), and the sixth channel (33) is a channel for the power fluid of the first nozzle (17).

7. The dual-string coiled tubing sand flushing and plugging removal device according to claim 1 is characterized by: The ground power fluid enters from the outer pipe port (22), enters the outer pipe (14) through the second channel (27), and then enters the double ejector (16) through the third channel (29), and is ejected from the first nozzle (17). The power fluid is also ejected from the second nozzle (20) at the same time.

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